[Federal Register: September 29, 2010 (Volume 75, Number 188)]
[Proposed Rules]
[Page 60036-60064]
[DOCID:fr29se10-30]

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DEPARTMENT OF TRANSPORTATION

National Highway Traffic Safety Administration

49 CFR Part 571

[Docket No. NHTSA-2010-0132]
RIN 2127-AK17

Federal Motor Vehicle Safety Standards; New Pneumatic Tires for
Motor Vehicles With a GVWR of More Than 4,536 Kilograms (10,000 Pounds)
and Motorcycles

AGENCY: National Highway Traffic Safety Administration (NHTSA),
Department of Transportation (DOT).

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This NPRM proposes to upgrade Federal Motor Vehicle Safety
Standard (FMVSS) No. 119, which specifies requirements for new truck
tires. We propose to amend FMVSS No. 119 to adopt more stringent
endurance test requirements and a new high speed test for several heavy
load range tires for vehicles with gross vehicle weight rating (GVWR)
of more than 4,536 kilograms (10,000 pounds). We are also proposing
that FMVSS No. 119 require that the tire sidewall be labeled with the
tire's maximum speed rating.

DATES: You should submit your comments early enough to ensure that the
Docket receives them not later than November 29, 2010.

ADDRESSES: You may submit comments (identified by the NHTSA Docket ID
Number above) by any of the following methods:
     Federal eRulemaking Portal: Go to http://
www.regulations.gov. Follow the online instructions for submitting
comments.
     Mail: Docket Management Facility: U.S. Department of
Transportation, 1200 New Jersey Avenue, SE., West Building Ground
Floor, Room W12-140, Washington, DC 20590-0001.
     Hand Delivery or Courier: West Building Ground Floor, Room
W12-140, 1200 New Jersey Avenue, SE., between 9 a.m. and 5 p.m. ET,
Monday through Friday, except Federal holidays.
     Fax:<PHONE_NUMBER>.
    Instructions: For detailed instructions on submitting comments and
additional information on the rulemaking process, see the Public
Participation heading of the Supplementary Information section of this
document. Note that all comments received will be posted without change
to http://www.regulations.gov, including any personal information
provided. Please see the Privacy Act heading below.
    Privacy Act: Anyone is able to search the electronic form of all
comments received into any of our dockets by the name of the individual
submitting the comment (or signing the comment, if submitted on behalf
of an association, business, labor union, etc.). You may review DOT's
complete Privacy Act Statement in the Federal Register published on
April 11, 2000 (65 FR 19477-78).
    Docket: For access to the docket to read background documents or
comments received, go to http://www.regulations.gov or the street
address listed above. Follow the online instructions for accessing the
dockets.

FOR FURTHER INFORMATION CONTACT: For technical issues, you may call
George Soodoo, NHTSA Office of Rulemaking (Telephone:<PHONE_NUMBER>)
(Fax:<PHONE_NUMBER>). For legal issues, you may call Steve Wood, NHTSA
Office of Chief Counsel (Telephone:<PHONE_NUMBER>) (Fax:<PHONE_NUMBER>).
The mailing address for these officials is: National Highway Traffic
Safety Administration, U.S. Department of Transportation, 1200 New
Jersey Avenue, SE., West Building, Washington, DC 20590.

SUPPLEMENTARY INFORMATION

Table of Contents

I. Background
II. Overview of Endurance Test and High Speed Test Proposals
    a. Endurance Test
    b. High Speed Test
III. NHTSA Tire Testing
    a. Test Program
    b. Summary
IV. Proposed Endurance Test
    a. Test Speed
    b. Load
    c. Inflation Pressure
    d. Duration
    e. Ambient Temperature
    f. Endurance Test Conclusions
V. Proposed High Speed Test
    a. Test Speed and Break-In Procedure
    b. Load
    c. Inflation Pressure
    d. Duration
    e. Ambient Temperature
VI. Tire Maximum Speed Marking
VII. Other Issues
    a. Alternatives Considered
    1. International Standards
    2. ASTM Truck/Bus Tire Test Development Task Group
    3. Rubber Manufacturers Association
    b. Deep Tread Truck Tires
    c. Correction of Table III
    d. Separate Standard
VIII. Proposed Effective Date
IX. Costs and Benefits
X. Rulemaking Analyses and Notices
XI. Public Participation

I. Background

    This NPRM proposes to upgrade Federal Motor Vehicle Safety Standard
(FMVSS) No. 119 (49 CFR 571.119) which, prior to the passage of the
Transportation Recall Enhancement, Accountability and Documentation
(TREAD) Act of 2000, had a wide application to new pneumatic tires for
vehicles other than passenger cars. In response to the TREAD Act,\1\ a
June 26, 2003 final rule upgraded the standard's requirements \2\ for
tires designed for multipurpose passenger vehicles, trucks and buses
with a GVWR of 4,536 kilograms (kg) (10,000 pounds (lb)) or less, and
moved those enhanced requirements to a new Federal Motor Vehicle Safety
Standard No. 139 for new pneumatic radial tires for light vehicles.
Requirements for load range C, D, and E tires used on light trucks and
vans formerly set forth in FMVSS No. 119 were thus moved from that
standard to FMVSS No. 139.\3\ The June 26, 2003 final rule changed the
title, scope, purpose and application sections of FMVSS No. 119 to
reflect that the standard thereafter applied to only tires for
motorcycles and vehicles with a GVWR greater than 4,536 kg (10,000 lb),
but made no changes to FMVSS No. 119's performance requirements for
those tires.\4\
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    \1\ Section 10 of the TREAD Act stated that the Secretary of
Transportation shall conduct a rulemaking to revise and update the
tire standards published at 49 CFR 571.109 and 49 CFR 571.119. The
Act provided that the Secretary shall complete the rulemaking under
this section not later than June 1, 2002. November 1, 2000, Public
Law 106-414, 114 Stat. 1800.
    \2\ 68 FR 38116; June 26, 2003, Docket NHTSA-03-15400; response
to petitions for reconsideration, 71 FR 877, January 6, 2006, Docket
2005-23439; technical amendments, 72 FR 49207, August 28, 2007,
Docket 2007-29083. See also final rule, correcting amendments, 73 FR
72357; November 28, 2008, Docket 2007-29083.
    \3\ The term ``load range'' with a letter (C, D, E, etc.) is
used to identify the load and inflation limits of tires used on
light or heavy trucks, which increase in alphabetical sequence. For
example, a load range E tire is able to handle greater loads and
higher inflation pressures than a load range D tire.
    \4\ FMVSS No. 119 has been in effect since the original rule was
published in 1973. The original standard applied to tires used on
vehicles other than passenger cars, which included pickup trucks,
multipurpose passenger vehicles, vans, and heavy vehicles. As a
result of the TREAD Act mandate to upgrade FMVSS No. 109 and FMVSS
No. 119, the agency revised the applicability of the tire standards
to reflect the weight of the vehicle on which the tire is used.
Given the increased consumer use to light trucks and vans (LTVs) for
passenger transportation purposes over the past 20 years, the agency
believed it was important to revise the applicability of the
standards. As a result, the new tire standard for light vehicle
tires, FMVSS No. 139, which was published in 2003, applies to tires
used on vehicles with a gross vehicle weight rating of 4,536 kg
(10,000 pounds) or less, and FMVSS No. 119 now applies to tires for
vehicles with a gross vehicle weight rating of over 4,536 kg (10,000
pounds). (It is noted that other tires required to comply with No.
119 are new pneumatic light truck tires with tread depth of 18/32
inch or greater, light truck bias-ply tires, bias-ply tires used on
vehicles with a GVWR of more than 4,536 kg (10,000 lb), and tires
for use on special-use trailer (ST, farm implement and 8-12 rim or
lower diameter code). The tires affected by this rulemaking are
those used on heavy vehicles with a GVWR of more than 4,536 kg
(10,000 lb) that are not for speed-restricted service.)
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    NHTSA stated in the NPRM developing FMVSS No. 139 that the TREAD
Act deadline to complete the tire upgrade by June 2002 did not allow
the agency time to study and analyze sufficiently the different issues
presented by medium and heavy vehicle tires, and that NHTSA will
examine these types of tires after completion of the FMVSS No. 139
rulemaking (67 FR 10050, 10061; March 5, 2002). In today's document, we
are proceeding to propose to make more stringent FMVSS No. 119's
endurance test, adopt a new high speed test for several load range
tires used on heavy vehicles, and require that the tire sidewall be
labeled with the tire's maximum speed rating.
    The agency is initiating this rulemaking to upgrade radial truck
tires that have a load range of F, G, H, J, and L, and that are not for
speed-restricted service (``non-speed-restricted service tires'').
Tires used for speed-restricted service, known as ``speed-restricted
service tires,'' are those with a maximum speed rating of 90 km/h (55
mph) or less. Non-speed-restricted service tires

are those with a maximum speed rating above 90 km/h (55 mph). ``Maximum
speed rating'' is the maximum speed, as specified by the manufacturer,
at which the tire can carry a load corresponding to its maximum load
rating for single usage at the corresponding inflation pressure.\5\ We
have commenced this rulemaking primarily because we have tentatively
determined that the FMVSS No. 119 performance tests developed in 1973
should be updated to reflect the increased operational speeds and
duration of truck tires in commercial service. NHTSA has tentatively
determined that this NPRM would have a beneficial effect on safety in
that it would increase tire durability as tires are held to more
stringent standards than currently required.
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    \5\ This NPRM would define these terms in FMVSS No. 119 to
differentiate the types of service for which tires are used and the
requirements in the standard that would apply to the different types
of tire.
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FMVSS No. 119

    FMVSS No. 119 specifies performance and marking requirements for
tires for use on motorcycles and on motor vehicles with a GVWR of more
than 4,536 kg (10,000 lb). Heavy vehicle tires regulated by FMVSS No.
119 are used in a wide variety of vehicle applications, such as
delivery trucks, line haul trucks, transit buses, and logging trucks.
FMVSS No. 119 includes a static test for tire strength, and dynamic
tests for tire endurance and high-speed performance. The endurance test
evaluates resistance to heat buildup when the tire is run at stepped-up
loads at or near its rated load nonstop for a total of 47 hours. A
high-speed test evaluates resistance to heat buildup when the tire is
run at a certain percentage of its maximum load at stepped-up speeds
for a specified interval at each speed.\6\ FMVSS No. 119's high-speed
performance requirement applies only to motorcycle tires and those with
a rim diameter code of 14.5 or less (tires made to fit rims of diameter
of 14.5 inches or less). Since this size restriction excludes all heavy
vehicle tires currently listed in the Tire and Rim Association 2009
Year Book, the endurance test is currently the only dynamic test to
which heavy vehicle tires must comply.
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    \6\ See, e.g., S6.2 of FMVSS No. 139.
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    Today's NPRM would upgrade FMVSS No. 119 by proposing to adopt a
more stringent endurance test, add a new high speed test, and include
maximum speed rating labeling requirements for new radial tires used on
heavy truck and bus applications, i.e., load range F, G, H, J, and L
tires that are not for speed-restricted service, which the agency
believes comprise about 98 percent of the truck tires sold in the
United States. These load range tires are typically used on heavy
trucks for regional haul and long haul operations as well as on
motorcoaches, and these load range tires have speed ratings ranging
from 55-81 mph. Higher load range tires (i.e., load ranges M and N) are
more often used in heavy mixed-use service (on/off-road operations in
lower speed applications), such as construction, logging, crane, and
rigging operations. However, the agency is also considering requiring
non-speed-restricted, load range M radial tires to comply with the
upgraded endurance and new high speed test because some of these tires
are used in similar applications in which the load range L tires are
used. The agency is not proposing to upgrade non-speed-restricted
service load range N radial tires since they represent less than 1
percent of the heavy vehicle tire market and are typically used in
lower speed operations.

II. Overview of Endurance Test and High Speed Test Proposals

    The proposed upgrade to the endurance test and the proposed
adoption of a high speed test are based on the results of NHTSA's heavy
truck tire tests, discussed later in the ``NHTSA Tire Testing'' section
of this preamble.

a. Endurance Test

    The purpose of the endurance test is to evaluate heavy truck tire
performance at highway speeds for a long duration. The endurance test
in FMVSS No. 119 applies to truck tires with load ranges F through N
that are not for speed-restricted service. The test parameters used for
the endurance test in FMVSS No. 119 include test speed, load, inflation
pressure, duration, and ambient temperature. This NPRM proposes to
upgrade the endurance test by changing some of these parameters to
achieve more stringent conditions when testing load range F, G, H, J,
and L radial tires that are not for speed-restricted service. Current
endurance test parameters for load range N radial tires, load range F,
G, H, J, L, M, and N tires that are for speed-restricted service, bias-
ply tires, light truck tires (tread depth 18/32 inch or more), and
motorcycle tires, would remain unchanged in the standard.
Test Speed
    The current test speed for the endurance test in FMVSS No. 119
depends on the load range of the tire. Load range F tires are tested at
64 km/h (40 mph) on the 67-inch diameter test road wheel; load range G
tires are tested at 56 km/h (35 mph); and tires with a load range H, J,
L, M, or N are tested at 48 km/h (30 mph). NHTSA proposes to raise the
test speed for the endurance test to 80 km/h (50 mph) for load range F,
G, H, J, and L tires. This represents a 25 percent increase in speed
for a load range F tire, a 43 percent increase for a load range G tire,
and a 67 percent increase for load range H, J, and L tires that are not
for speed-restricted service.
Load
    The current test loads for the endurance test in FMVSS No. 119,
identical for all the load ranges F through N, are specified as a
percentage of the maximum load rating of the tire, and are 66 percent,
84 percent, and 101 percent. The loads are applied in a stepped fashion
for durations of 7 hours, 16 hours, and 24 hours, respectively. NHTSA
proposes to change the load combination for the endurance test to 85/
90/100 percent of the tire's maximum load rating labeled on the tire's
sidewall, from the 66/84/101 percent combination currently required.
Inflation Pressure
    The current test inflation pressure specified in FMVSS No. 119 is
the inflation pressure corresponding to the maximum load rating labeled
on the tire's sidewall. NHTSA proposes to set the test inflation
pressure at 80 percent of the sidewall-labeled inflation pressure that
corresponds to the tire's maximum load rating. This represents a 20
percent decrease from the current endurance test, which requires tires
to be fully inflated.
Duration
    The current duration for the endurance test in FMVSS No. 119 is 47
hours: 7 hours at 66 percent load, 16 hours at 84 percent load, and 24
hours at 101 percent load. NHTSA proposes to leave FMVSS No. 119's
endurance test duration at 47 hours.
Ambient Temperature
    The ambient temperature specified for the endurance test in FMVSS
No. 119 is 35 [deg]C (95 [deg]F). NHTSA proposes to add an ambient
temperature tolerance, and thus proposes an ambient of 35 [deg]C  3 [deg]C (95 [deg]F  5 [deg]F) for the endurance
test.

b. High Speed Test

    The high speed test evaluates tire performance at higher speeds for
shorter durations. FMVSS No. 119's high speed test currently applies
only to motorcycle tires and to tires with rim diameters of 14.5 inches
or below, and does not

apply to truck tires. The test parameters used for the high speed test
in FMVSS No. 119 and in other tire standards include speed, load,
inflation pressure, duration, and ambient temperature. This NPRM
proposes to adopt a high speed test for load range F, G, H, J, and L
tires that are not for speed-restricted service, as these are typically
installed on vehicles in regional or long-haul service. The high-speed
test would be initiated after a 2-hour break-in at 80 km/h (50 mph) and
85 percent of maximum load rating, with inflation pressure at 90
percent of maximum.
Test Speed
    NHTSA proposes to set the test speed for the high-speed test at the
tire's maximum speed less 20 km/h (12 mph) for step 1, maximum speed
less 10 km/h (6 mph) for step 2, and at maximum speed for the final
step. This would be a new approach for testing tires under the Federal
motor vehicle safety standards, as motorcycle and passenger car tires
are tested to one unvarying set of test speeds. The approach proposed
in this NPRM is similar to that used by the United Nations Economic
Commission for Europe (ECE) tire Regulations which establish tire test
speeds based on the maximum rated speed of the tire, and is along the
lines of a suggestion from the Rubber Manufacturers Association
(RMA).\7\
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    \7\ See Docket No. NHTSA 2002-13707-0016.1, RMA Perspective on
the FMVSS 119 Revisions and Updates Mandated by the TREAD Act.
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Load
    NHTSA proposes to set the test load for the high-speed test at 85
percent of the maximum load rating for the tire. The maximum load
rating would be based on the tire sidewall marking per single tire use
application.
Inflation Pressure
    NHTSA proposes that the high-speed test inflation pressure be set
at 90 percent of the sidewall-labeled inflation pressure that
corresponds to the tire's maximum load rating.
Duration
    NHTSA proposes a 90-minute duration for FMVSS No. 119's high-speed
test, consisting of three 30-minute speed steps at the proposed test
speeds.
Ambient Temperature
    NHTSA proposes an ambient temperature range of 35 [deg]C  3 [deg]C (95 [deg]F  5 [deg]F) for the FMVSS No. 119
high speed test upgrade.

III. NHTSA Tire Testing

a. Test Program

    After passage of the TREAD Act, NHTSA began testing new heavy truck
tires to assess the performance of current tires in endurance and high
speed tests, and how load, inflation pressure, speed and duration
affect tire performance. We tested more than 430 new heavy truck tires
with load ranges G through N that were designed for commercial vehicle
applications. The tires selected included a mixture of tire brands,
models and sizes.
    Testing was performed in two phases. In Phase I, new load range G
tires were tested for durability (``endurance'') and robustness at
speed (``high speed''). Since the purpose of Phase I testing was to
assess the current level of performance for truck tires, the test
matrix for this phase included both destructive (extended duration) and
non-destructive tests. The purpose of Phase II testing was to generate
data with which specific proposals could be developed for an NPRM to
upgrade FMVSS No. 119. In Phase II, the test conditions were further
refined from Phase I, and the group of tires tested was expanded to
include load ranges H, J, L and N. Additional testing was also
conducted for tires with load ranges F, J, and L, and speed ratings
less than 75 mph.
    All of the tires tested were commercially available at the time of
testing. For both Phases I and II, NHTSA developed test matrices that
included the performance parameters of speed, load, inflation pressure,
and test duration. The test matrices were developed with a series of
test conditions that increased in severity for tire performance. The
ambient temperature used in the testing for both Phase I and Phase II
was 35 [deg]C  3 [deg]C (95 [deg]F  5 [deg]F).
All tires were conditioned at the ambient temperature of 35 [deg]C
 3 [deg]C (95 [deg]F  5 [deg]F) for 3 hours
prior to testing. Testing was conducted on a 67-inch diameter curved
test road wheel.\8\
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    \8\ Throughout this preamble, we use test speeds in miles per
hour (mph) when presenting the test matrices, the test conditions,
and the test results for the baseline tests, as specified in the
current FMVSS No. 119. However, for the other tests in both the
endurance and high speed test matrices, we selected test speeds in
kilometers per hour (km/h) to be consistent with the metrification
of the Federal motor vehicle safety standards. Some of the Tables
presented in the preamble show speeds in miles per hour only, to
facilitate comparison with the baseline test speeds.
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Phase I Testing
    In Phase I, NHTSA conducted testing on 180 new, size 11R22.5, load
range G, heavy truck tires with a rib-type tread.\9\ The 11R22.5 tire
size was chosen due to its use in on-road applications for heavy
vehicles: tire size 11R22.5 represents approximately 24 percent and 22
percent of the original equipment and replacement tire markets,
respectively. We tested tires from brands Hankook, Dayton, Bridgestone,
and General, all with tire size 11R22.5, load range G, and rib-type
treads. Based on suggestions \10\ from the Rubber Manufacturers
Association (RMA), the Tire Industry Association (TIA), and the Tread
Rubber/Tire Repair Materials Manufacturers Group (TRMG), we tested only
rib-type tires, typically used on steer axle and trailer axle
positions, to focus on a single tread type. Tires were tested to
determine levels of endurance and high-speed performance under a
variety of test conditions.
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    \9\ In the tire size description, the ``11'' represents the tire
section width in inches, the ``R'' identifies the tire as a radial
tire, and the ``22.5'' represents the tire rim diameter code, which
equates to a rim diameter of 22.5 inches.
    \10\ See Docket No. NHTSA-2002-13707.
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    Phase I Endurance Test:
    For the endurance test, we selected 120 new load range G tires from
Hankook, Dayton, Bridgestone and General. The Phase I endurance test
matrix consisted of 10 groups of varied test conditions, or ``Test
Methods,'' \11\ as shown below in Table 1, ``Phase I Endurance Test
Matrix.'' Other than in Test Methods 1 and 1A, three samples of each
tire brand were tested for each Test Method (TM) in the matrix. Test
Method 1 used one sample of each tire brand, and Test Method 1A used
two samples of each tire brand.
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    \11\ Test Method 1A is considered a part of Test Method 1.
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    Each TM consisted of a combination of the selected tire load,
inflation pressure, test speed, and a specified duration at each load
condition. Testing was performed so that each TM varied in severity by
changing the load, inflation pressure or speed.
    The applied test loads ranged from 66 percent of the maximum load
rating to 110 percent of the maximum load rating. The loads used are
similar to those used in the light vehicle tire research program that
was conducted in 2001-2002 to support the upgrade of the endurance test
for FMVSS No. 139. The stepped-up load combinations included 85, 90,
and 100 percent; 90, 100, and 110 percent; and 100, 110, and 115
percent, which allowed the agency to understand limits of performance
for light vehicle tires, including light truck tires with load ranges
C, D, and E. For this research on medium and heavy duty truck tires,
the agency also wanted

to understand the upper limits of performance for these tires when they
are tested at normal loading conditions and at loads beyond their
maximum load rating. As a result, we included stepped-up loads to 90/
100/110 percent of the maximum load rating of the tires, since this
represents an overloading condition for a truck tire on the test road-
wheel.
    Inflation pressures ranged from 80 to 100 percent of the maximum
inflation pressure stated on the sidewall of the tires. The current
endurance test in FMVSS No. 119 requires that the tire be tested at 100
percent of its maximum inflation pressure, but the agency sought to
evaluate truck tires' performance when tested at some level of under-
inflation, because that condition is occurring in real-world
operation.\12\ We chose 80 percent of the maximum inflation pressure as
the lowest value for this testing, primarily because the truck industry
considers a tire at that level of under-inflation to be significantly
under-inflated.
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    \12\ See Federal Motor Carrier Safety Administration, Final
Report, ``Commercial Vehicle Tire Condition Sensors,'' November
2003, at 7.
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    The test speeds ranged from 56 km/h (35 mph) to 120 km/h (75 mph),
which we believe represented the typical operating range of speeds for
trucks using tires with the specified load ranges. Each tire was
conditioned at the ambient test temperature of 35 [deg]C  3
[deg]C (95 [deg]F  5 [deg]F) for three hours. No break-in
procedure was performed on tires tested for endurance performance since
none is performed in the existing FMVSS No. 119 endurance test
procedure. Table 1, ``Phase I Endurance Test Matrix,'' below shows the
test parameters used for the endurance test in Phase I and the
structure of the test duration for the three samples in each Test
Method. We note that for TMs 2-9, tire sample number 3 was tested for
an additional amount of time after the rest of the TM was completed,
which is why Table 1 shows an extra line for sample number 3 for these
TMs.

[GRAPHIC] [TIFF OMITTED] TP29SE10.005

[GRAPHIC] [TIFF OMITTED] TP29SE10.006

    The test parameters for the baseline tests (Test Method 1, load
step 1-3) represent the current FMVSS No. 119 level for the endurance
test. The tires (one sample of each tire brand) were tested at 56 km/h
(35 mph), with a load of 66 percent of maximum load rating for 7 hours,
84 percent of maximum load rating for 16 hours, 101 percent of maximum
load for 24 hours, and with an inflation pressure of 100 percent of the
maximum inflation pressure value labeled on the sidewall. After the end
of the 47-hour test, the tires were tested for an additional 48 hours,
at a load of 110 percent of maximum load rating, and with the test
parameters of speed, inflation pressure, and ambient temperature
unchanged. Therefore, the total duration for the baseline endurance
tests in Test Method 1 was 95 hours (47 hours per FMVSS No. 119 plus an
additional 48 hours).
    There were no failures in the baseline tests completed on the first
of three samples for each tire brand. We then conducted a second
baseline test by increasing the test speed for the remaining two
samples to 80 km/h (50 mph) for the entire test, as shown in Test
Method 1A. The inflation pressure and load parameters for the second
baseline test were the same as in Test Method 1. The test load for the
remaining two samples was 110 percent of maximum load rating for the
last 48 hours of the test. The objective of the baseline tests in Test
Method 1A was to determine how well tires performed under conditions
slightly more stringent than the current endurance test in FMVSS No.
119.
    As shown in Test Methods 2 through 9 (Table 1, above), test
severity was increased by increasing the test speed, increasing the
test loads, and reducing the inflation pressure. Road-wheel tests (not
to failure) were conducted for 47 hours on two samples. The third
sample was tested to 95 hours or until failure, whichever occurred
first, with the load for the last 48 hours of the test being the same
load applied in the last step for the 47-hour portion of the test.
    All tires were inspected for belt separation, tread separation, and
any other visual evidence of damage. For Test Method 10, all three tire
samples were tested to 95 hours or until failure, whichever occurred
first.
    Phase I Endurance Test Results:
    Of the 120 new tires tested for endurance performance under a
variety of test conditions, 24 experienced failures. Of the 24
failures, 15 failed as a result of tread separation, 2 failed as a
result of belt separation; 2 failed as a result of shoulder split; and
2 failed as a result of chunking. The remaining 3 failures consisted of
other failure types such as tread splitting and sidewall separation.
Table 2, ``Phase I Endurance Test Results,'' summarizes the results for
the endurance test on the four tire brands tested. Data for individual
tests have been placed in the docket (NHTSA-2002-13707).
    The Test Methods included in Table 2 are the same test methods for
which the test conditions are shown in detail in Table 1. The test
results in Table 2 show that the first sample for each of the four tire
brands completed 95 hours for the baseline test in Test Method 1. The
remaining two tire samples for each brand were tested to Test Method
1A, using the same test parameters, except for the test speed, which
was increased from 56 km/h (35 mph) to 80 km/h (50 mph). Also note that
for Test Methods 2 through 10, the first two samples of each Test
Method were tested to 47 hours, while the third sample was tested to 95
hours. Four test errors occurred, where the test road-wheel stopped due
to equipment or mechanical failure. These test errors are noted in
Table 2 with an asterisk.

                                                         Table 2--Phase I Endurance Test Results
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                                                                   Tire brands (hours completed)
                                                         -----------------------------------------------------------------------------------------------
                                      Target (hours)
                                          Hankook
                                          Dayton
                                        Bridgestone
                                          General
                                 -----------------------------------------------------------------------------------------------------------------------
         Test Method No.                                                                Sample No.
                                 -----------------------------------------------------------------------------------------------------------------------
                                      1       2       3       1       2       3       1       2       3       1       2       3       1       2       3
--------------------------------------------------------------------------------------------------------------------------------------------------------
1...............................     95   ......  ......     95   ......  ......     95   ......  ......     95   ......  ......     95   ......  ......
1A..............................  ......     95      95   ......     95      95   ......     95      95   ......     95      95   ......     95      95
2...............................     47      47      95      47      47      95      47      47      95      47      47      95      47      47      95
3...............................     47      47      95       1      47      95      47      47      95      47      47      95      47      47      95
4...............................     47      47      95      47      47      95      47      47      37      47      47      37      47      47      95
5...............................     47      47      95      47      47      95      43      44      53      47     44*      95      47      47      95
6...............................     47      47      95      47      47      95      47      47      95      47      47      95      47      47      95
7...............................     47      47      95      47      47      95      47      47      69      47      47      95      47      47      95
8...............................     47      47      95      47     44*      95      47      47      95      47      47      92      47      47      32
9...............................     47      47      95      47      47      95      28      28      23      47      47      95      42      47      41
10..............................     47      47      95      12      50     46*      27       3      14     31*      27      30      25      36      24
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note: * Test error.

    Overall, the tires tested performed well throughout the endurance
test matrix, particularly Test Methods 1 through 8, for which each tire
brand had at least one sample that completed 47 hours of those Test
Methods. The results indicate that decreased inflation pressure and
increased speed of Test Method 9, and the even higher speed of Test
Method 10, define the upper boundary of current new tire performance.
For Test Methods 8 and 9, the inflation pressure was decreased to 80
percent of maximum inflation pressure, and the test speed was increased
from 88 km/h (55 mph) to 100 km/h (63 mph). In addition, the test loads
were increased in Test Method 9 to 90/100/110 percent of the tire's
maximum load rating. For Test Method 10, inflation was increased to 100
percent and test speed raised to 120 km/h (75 mph), the same test speed
used in the endurance test for light vehicle tires in FMVSS No. 139.
The results indicate that higher speeds and lower inflation pressure
appear to have the most impact on tire failure compared with changes in
test load or duration.
    Phase I High Speed Test:
    We tested 60 new load range G tires from major tire manufacturers
Hankook, Dayton, Bridgestone, and General for high speed performance.
Since the FMVSS No. 119 high speed requirements currently apply only to
tires with a rim diameter code of 14.5 or less and to motorcycle tires,
the performance levels for the high speed baseline tests in our heavy
truck tire test program (see Test Method A of Table 3 below, ``Phase I
High Speed Test Matrix'') were set at the FMVSS No. 119 levels of
performance for those tires, simply as a starting point for the test
program. Test conditions were varied to produce different levels of
severity by changing the load, inflation pressure and speed. See Table
3, ``Phase I High Speed Test Matrix,'' below for a summary of the high
speed test matrix.

[GRAPHIC] [TIFF OMITTED] TP29SE10.007

    Test severity, as defined by more severe running conditions (i.e.
increased load, higher speed, or reduced inflation pressure), increased
from Test Method A to Test Method E. In Test Method A, the first three
speed steps represent the current conditions in FMVSS No. 119
(specified for applicable tires) and the next three test speeds
represent speed conditions beyond those currently in FMVSS No. 119. The
tires were tested to a stepped-up speed profile starting at 120 km/h
(75 mph), with a load condition of 88 percent of maximum load rating
for 30 minutes. The test speed was increased in 5-mph increments every
30 minutes until failure or a speed of 160 km/h (100 mph) was achieved,
whichever occurred first. Therefore, the target completion time for the
baseline high speed test was 3 hours for a total of six speed steps for
Test Method A only. The primary reason for testing beyond 137 km/h (85
mph) in the baseline tests was to assess the upper boundary of high
speed performance for heavy truck tires.
    The initial test speed for Test Methods B through E was set to 120
km/h (75 mph), and increased to 130 km/h (81 mph) and 140 km/h (88 mph)
in 30-minute intervals for a total of three test steps. The 10-km/h
increments were used to increase the speed severity moderately for tire
samples as they advanced through the different test methods. For each
tire brand tested, the first two samples were tested for three 30-
minute speed steps, for a total test duration of 1.5 hours. The third
sample was tested for an additional hour at the last speed step of 140
km/h (88 mph), resulting in a test duration of 2.5 hours.
    The test load was based on the maximum load rating for the subject
tire as labeled on the sidewall. The test load ranged from 80 percent
of maximum load rating to 90 percent of maximum load rating. Inflation
pressures ranged from 90 percent to 100 percent of maximum pressure
labeled on the sidewall.
    Each tire was conditioned for the test at an ambient temperature of
35 [deg]C  3 [deg]C (95 [deg]F  5 [deg]F) for
three hours, and then broken in for two hours under 88 percent of
maximum load and 100

percent maximum inflation pressure at 80 km/h (50 mph).\13\ The tire
was allowed to cool to 35 [deg]C  3 [deg]C (95 [deg]F
 5 [deg]F) and the inflation pressure was adjusted to
applicable pressure immediately before the test. The break-in procedure
was performed to bring the tire to operating temperature, which allows
the tire to flex, expand and contract such that air within the tire may
fully permeate into the tire cavity. The break-in procedure also
removes mold release agents and flashings produced by the molding
process, which could contribute to variability in the test.
---------------------------------------------------------------------------

    \13\ Traditionally, a high speed test has an initial break-in
step that involves a tire running on the roadwheel under specified
conditions to allow for tire growth. The endurance test does not
need a break-in step primarily because the 47-hour test duration
allows time for break-in during the test.
---------------------------------------------------------------------------

    At the completion of the test, tires were visually inspected for
belt separation, tread separation, and evidence of damage.
    Phase I High Speed Test Results:
    Of the 60 new tires tested for high speed performance under a
variety of test conditions, 7 experienced test failures. Of these 7
failures, 4 failed as a result of tread chunking, 2 failed as a result
of tread separation, and 1 failed due to belt separation. Most of these
failures occurred in Test Method A at test speeds of 152 km/h (95 mph)
or at 160 km/h (100 mph). Table 4 below, ``Phase I High Speed Test
Results (Hours Completed),'' shows how the tires performed, as tested
under each test method. The Test Methods included in Table 4 are the
same Test Methods for which the test conditions are shown in detail in
Table 3.

                                               Table 4--Phase I High Speed Test Results (Hours Completed)
--------------------------------------------------------------------------------------------------------------------------------------------------------

--------------------------------------------------------------------------------------------------------------------------------------------------------

                                                                   Tire Brands (hours completed)
                                                         -----------------------------------------------------------------------------------------------
                                       Target hours
                                          Hankook
                                          Dayton
                                        Bridgestone
                                          General
                                 -----------------------------------------------------------------------------------------------------------------------
           Test Method                                                                  Sample No.
                                 -----------------------------------------------------------------------------------------------------------------------
                                      1       2       3       1       2       3       1       2       3       1       2       3       1       2       3
--------------------------------------------------------------------------------------------------------------------------------------------------------
A...............................    3.0     3.0     3.0     3.0     3.0     3.0     2.3     2.8     2.5     2.9     3.0     2.9     3.0     3.0     2.8
B...............................    1.5     1.5     2.5     1.5     1.5     2.5     1.5     1.5     2.5     1.5     1.5     2.5     1.5     1.5     2.5
C...............................    1.5     1.5     2.5     1.5     1.5     2.5     1.5     1.5     2.5     1.5     1.5     2.5     1.5     1.5     2.5
D...............................    1.5     1.5     2.5     1.5     1.5     2.5     1.5     1.5     2.5     1.5     1.5     2.5     1.5     1.5     2.5
E...............................    1.5     1.5     2.5     1.5     1.5     2.5     1.5     1.5     1.8     1.5     1.5     2.5     1.5     1.5     2.5
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Test Method A was extended so that samples would be tested to the
baseline FMVSS No. 119 conditions and then tested at increased speeds.
For Test Method A, speed was increased beyond the FMVSS No. 119 test
speeds to 90, 95, and 100 mph, in 30-minute increments (the total test
duration target was three hours). Inflation pressure and load were
unchanged. Each sample was tested at 88 percent of maximum load rating,
100 percent inflation pressure and to speeds that were increased in 30-
minute increments to a stepped profile, initiating at 120 km/h (75 mph)
and concluding at 160 km/h (100 mph) or failure, whichever occurred
first.
    Overall, the new tires tested to the high-speed matrix performed
well, as shown in Table 4. All of the 7 tires that failed completed at
least 1.5 hours, which represents the first three 30-minute speed steps
of the targeted test duration. Test Method A was designed to test tires
to 100 mph or failure, whichever occurred first. The results for Test
Method A reveal that all of the tires were able to withstand speeds of
up to 90 mph, when inflated at 100 percent of maximum inflation
pressure. The results also show that all of the tires tested to Test
Methods B through E were able to complete the 1.5 hours at test speeds
of 120, 130, and 140 km/h (75, 81 and 88 mph). In addition, when tested
to an additional hour at the last speed step of 140 km/h (88 mph), all
the tires tested, except one Dayton tire, were able to complete the
entire 2.5 hours of the high-speed test.

Phase II Testing

    While Phase I testing provided NHTSA with a general understanding
of the current level of performance for new heavy duty truck tires,
Phase II testing refined the test matrices to develop possible,
practicable, proposals to upgrade the endurance and high speed tests in
FMVSS No. 119. In Phase II, NHTSA tested 365 new tires. Testing also
was expanded to include test tires of additional tire sizes (385/65 R
22.5 and 315/80 R 22.5), load ranges (F, H, J, L, and N tires, and load
range G ``bias ply'' type tires), brands from other manufacturers
(Continental, Goodyear, Michelin, Kumho, and Yokohama), and steer,
drive, and all-position tread types, as shown in Table 5.
    These tires included speed ratings ranging from 56 mph to 75 mph.
Most of the tires were tested for both endurance performance and for
high-speed performance. Some tire models were tested in 2005, and
certain tire models tested were retested in 2008 to validate their
performance. In the results section, superscripts were used to identify
which tires were tested first. FMVSS No. 119 does not apply to speed-
restricted service and bias-ply tires, therefore those tires were not
included in the costs and benefits analysis section. The data for those
tires were collected to learn about their performance levels. Of the
365 tires tested, 159 tires were tested to the proposed methods.
Seventy-eight tires were tested for Endurance and 81 were tested for
High Speed performance.

                                       Table 5--Phase II Tire Information
----------------------------------------------------------------------------------------------------------------
                                                                              Max speed
           Group No.                Manufacture/model      Tire size and LR     (mph)          Application
----------------------------------------------------------------------------------------------------------------
1..............................  Goodyear G647 RSS......  225/70R19.5 LR F.          75  Regional/P&D
2..............................  Michelin XRV...........  225/70R19.5 LR F.          75  Long haul
3..............................  Bridgestone R293.......  11R24.5 LR G.....          75  Long haul

4..............................  Bridgestone M1X 711....  11R24.5 LR G.....          75  Long haul
5..............................  General D460...........  11R24.5 LR G.....          75  Long haul
6..............................  Michelin XZY3..........  11R24.5 LR G.....          65  Mixed service
7..............................  General S580...........  11R24.5 LR H.....          75  Long haul
8..............................  Goodyear G167..........  11R24.5 LR H.....          75  Long haul
9..............................  Goodyear G395..........  11R24.5 LR H.....          75  Long haul
10.............................  Goodyear Marathon LHT..  245/70R17.5 LR H.          62  N/A
11.............................  Kumho 943..............  11R24.5 LR H.....          75  Regional/P&D
12.............................  Kumho KRS02............  11R24.5 LR H.....          75  N/A
13.............................  Yokohama TY303.........  11R24.5 LR H.....          75  Long haul
14.............................  Yokohama RY023.........  11R24.5 LR H.....          75  Long haul
15.............................  Bridgestone R184 CZ....  215/75R17.5 LR H.          65  High Load Trailer
16.............................  Bridgestone L320.......  11.00R24.5 LR H..          65  Mixed service
17.............................  Goodyear Unisteel G291.  315/80R22.5 LR J.          75  Regional/P&D
18.............................  Goodyear G286 (wb).....  385/65R22.5 LR J.          68  Mixed service
19.............................  Michelin XZY3 (wb).....  385/80R22.5 LR J.          65  Mixed service
20.............................  Michelin XTA...........  215/75R17.5 LR J.          62  L. haul/Regional
21.............................  Kumho KRT02............  235/75R17.5 LR J.          62  Regional/P&D
22.............................  Yokohama RY253 (wb)....  385/65R22.5 LR J.          65  Long haul
23.............................  Continental HMS 45+....  315/80R22.5 LR L.          56  Mixed service
24.............................  Michelin XZUS..........  315/80R22.5 LR L.          65  Regional/P&D
25.............................  Michelin XZA2 Energy...  315/80R22.5 LR L.          75  Long haul
26.............................  Milestar TRX (bias-ply)  N/A LR G.........         N/A  N/A
27.............................  Prime X Rockmaster.....  N/A LR N.........         N/A  N/A
----------------------------------------------------------------------------------------------------------------
Note: (wb) means it is a wide-base tire; * means speed-restricted service tire.

Phase II Endurance Test

    NHTSA tested new tires with load ranges F, G, H, J, L and N from
several major tire manufacturers. Table 6, ``Phase II Endurance Test
Matrix,'' shows the endurance test conditions used for Phase II
testing. These test conditions were selected based on our analysis of
the Phase I results. We varied the severity of the test conditions by
adjusting load, inflation pressure and/or speed. For each test method,
the test load was stepped-up through 85, 90, and 100 percent of maximum
load rating. Inflation pressures ranged from 80 percent to 90 percent
of maximum inflation pressure stated on the sidewall. Test speeds
ranged from 80 km/h (50 mph) to 100 km/h (62 mph). Each tire was
conditioned at ambient temperature 35 [deg]C  3 [deg]C (95
[deg]F  5 [deg]F) for three hours. All the tires were
tested for a total duration of 71 hours consisting of the 47 hours of
the current FMVSS No. 119 endurance test plus an additional 24 hours.

[GRAPHIC] [TIFF OMITTED] TP29SE10.008

    The results of the endurance tests for new tires in Phase I
indicated that higher speeds and lower inflation pressure appear to
have the most impact on tire failure compared with changes in test load
or duration. Based on these results, in the Phase II program NHTSA
decided to moderately increase the severity of its endurance test
matrix over the current requirements in FMVSS No. 119. The least severe
test condition, Test Method 1, had the lowest test speed (80 km/h or 50
mph), and the highest inflation pressure (90 percent of maximum
inflation pressure). The most severe test condition, Test Method 6, had
the highest test speed (100 km/h or 62 mph), and the lowest inflation
pressure (80 percent of maximum inflation pressure).

Phase II Endurance Test Results

    Tables 7 through 14 of this preamble, below, summarize the results
of the endurance testing in Phase II. The results indicate that as the
test severity increased, in going from Test Method 1 to Test Method 6,
tire failure rate increased. Tires tested under Test Method 1 were more
likely to achieve the target of 71 hours compared to tires tested to
Test Method 6. All of the load range G (radial) and H tires tested
under Test Methods 1 and 2 achieved the target of 71 hours, whereas
only a few of the load range G tires and none of the load range H tires
tested to Test Methods 5 and 6 were able to achieve the target of 71
hours. The dashes in the tables represent Test Methods that were not
performed for that specified tire.
    Three tire groups (Nos. 10, 20, and 21) were speed-rated 62 mph.
These groups were tested with a variation in speed. Samples 1
from these three tire groups were tested at 50 mph. If sample
1 did not complete the 71-hour test, sample 2 was
tested at 45 mph and sample 3 was tested at 40 mph. If sample
1 completed the 71-hour test at 50 mph, the remaining samples
were tested at the same speed.

                             Table 7--Phase II Endurance Test Results, Load Range F
----------------------------------------------------------------------------------------------------------------

----------------------------------------------------------------------------------------------------------------
                                             Proposed (hours)
                                                   Tire Brands (Hours Completed)
                                                                 -----------------------------------------------

                                             Goodyear 647 RSS
                                               Michelin XRV
                                         -----------------------------------------------------------------------
             Test Method No.                                            Sample No.
                                         -----------------------------------------------------------------------
                                              1       2       3       1       2       3       1       2       3
----------------------------------------------------------------------------------------------------------------
2.......................................     47      47      47      71      71      71      71      71      71
----------------------------------------------------------------------------------------------------------------

                                                 Table 8--Phase II Endurance Test Results, Load Range G
--------------------------------------------------------------------------------------------------------------------------------------------------------

--------------------------------------------------------------------------------------------------------------------------------------------------------

                                                                               Tire Brands (Hours Completed)
                                                                                -----------------------------------------------------------------------
                                                             Proposed (hours)
                                                            Bridgestone R293--
                                                                   Steer
                                                           Bridgestone MIX 711--
                                                                   Drive
                                                            General D460--Drive
                                                         -----------------------------------------------------------------------------------------------
                     Test Method No.                                                                Sample No.
                                                         -----------------------------------------------------------------------------------------------
                                                              1       2       3       1       2       3       1       2       3       1       2       3
--------------------------------------------------------------------------------------------------------------------------------------------------------
1.......................................................     47      47      47      71      71      71      71      71      71   ......  ......  ......
2.......................................................     47      47      47      71      71      71      71      71      71      71      71      71
3.......................................................     47      47      47      71      71      71      71      71      65   ......  ......  ......
4.......................................................     47      47      47      71      71      71      71      71      71   ......  ......  ......
5.......................................................     47      47      47      71      71      44      40      37      32   ......  ......  ......
6.......................................................     47      47      47      24      71      33      33      33      34   ......  ......  ......
--------------------------------------------------------------------------------------------------------------------------------------------------------

                                                                     Table 9--Phase II Endurance Test Results, Load Range H
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

                                                                                Group Samples (Hours Completed)
                                                                         -----------------------------------------------------------------------------------------------------------------------
                                                     Proposed (hours)
                                                   Goodyear G395--Steer
                                                   Goodyear G167--Drive
                                                     Kumho 943--Drive
                                                    Kumho KRS02--Drive
                                                   Yokohama RY023--Steer
                                                 -----------------------------------------------------------------------------------------------------------------------------------------------
                 Test Method No.                                                                                Sample No.
                                                 -----------------------------------------------------------------------------------------------------------------------------------------------
                                                      1       2       3       1       2       3       1       2       3       1       2       3       1       2       3       1       2       3
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
1...............................................     47      47      47      71      71      71      71      71      71      71   ......  ......  ......  ......  ......  ......  ......  ......
2...............................................     47      47      47      71      71      71      71      71      71      71      71      71      71      71      71      71      71      71
3...............................................     47      47      47      41      35      50      46      69      71   ......  ......  ......  ......  ......  ......  ......  ......  ......
4...............................................     47      47      47      71      55      56      47      48      56   ......  ......  ......  ......  ......  ......  ......  ......  ......
5...............................................     47      47      47      18      19      19      24       5      27   ......  ......  ......  ......  ......  ......  ......  ......  ......
6...............................................     47      47      47      13      25      17      19       8       7   ......  ......  ......  ......  ......  ......  ......  ......  ......
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

                                                                     Table 10--Phase II Endurance Test Results, Load Range H
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

                                                                                Group Samples (Hours Completed)
                                                                         -----------------------------------------------------------------------------------------------------------------------
                                                     Proposed (hours)
                                                   Goodyear Marathon LHT
                                                    Bridgestone R184 CZ
                                                     Bridgestone L320
                                                      Yokohama TY303
                                                       General S580
                                                 -----------------------------------------------------------------------------------------------------------------------------------------------
                 Test Method No.                                                                                Sample No.
                                                 -----------------------------------------------------------------------------------------------------------------------------------------------
                                                      1       2       3       1       2       3       1       2       3       1       2       3       1       2       3       1       2       3
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
2...............................................     47      47      47      22      30      35      71      71      71      71      71      71      71      71      71      71      71     71
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Samples 2 and 3 from Goodyear LHT were tested at 45 and 40 mph.

                                                                     Table 11--Phase II Endurance Test Results, Load Range J
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

                                                                                Tire Brands (Hours Completed)
                                                                         -----------------------------------------------------------------------------------------------------------------------
                                                     Proposed (hours)
                                                   Yokohama RY253 (wb)--
                                                         All Pos.
                                                   Goodyear G286 (wb)--
                                                           Steer
                                                     \1\ Michelin XZY3
                                                      (wb)--All Pos.
                                                  Goodyear Unisteel G291
                                                     \2\ Michelin XZY3
                                                      (wb)--All Pos.
                                                 -----------------------------------------------------------------------------------------------------------------------------------------------
                 Test Method No.                                                                                Sample No.
                                                 -----------------------------------------------------------------------------------------------------------------------------------------------
                                                      1       2       3       1       2       3       1       2       3       1       2       3       1       2       3       1       2       3
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
1...............................................     47      47      47      71      71      71       7       4       7      71      71      71   ......  ......  ......  ......  ......  ......
2...............................................     47      47      47      71      71      71       7       5       7      65      44      71      71      71      71      71      65      71
3...............................................     47      47      47      55      45      42       2       2       5       6      70      44   ......  ......  ......  ......  ......  ......
4...............................................     47      47      47      42      43      34   ......  ......  ......  ......  ......  ......  ......  ......  ......  ......  ......  ......
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Superscripts 1 and 2: 1 represents tires tested in 2005; 2 represents tires tested in 2008.

                                                 Table 12--Phase II Endurance Test Results, Load Range J
--------------------------------------------------------------------------------------------------------------------------------------------------------

--------------------------------------------------------------------------------------------------------------------------------------------------------

                                                                              Group Samples (Hours Completed)
                                                                                -----------------------------------------------------------------------
                                                             Proposed (hours)
                                                            \2\ Yokohama RY253
                                                                   (wb)
                                                               Michelin XTA
                                                                Kumho KRT02
                                                         -----------------------------------------------------------------------------------------------
                     Test Method No.                                                                Sample No.
                                                         -----------------------------------------------------------------------------------------------
                                                              1       2       3       1       2       3       1       2       3       1       2       3
                                                         -----------------------------------------------------------------------------------------------
2.......................................................     47      47      47      71      71      71      71      71      71      27      56     71
--------------------------------------------------------------------------------------------------------------------------------------------------------
Samples 2 and 3 from Kumho KRT02 were tested at 45 and 40 mph.

                                                                     Table 13--Phase II Endurance Test Results, Load Range L
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

                                                                                Tire Brands (Hours Completed)
                                                                         -----------------------------------------------------------------------------------------------------------------------
                                                     Proposed (hours)
                                                    \1\ Conti. HMS45 +
                                                           Steer
                                                  \1\ Michelin XZUS--All
                                                           Pos.
                                                     \1\ Michelin XZA2
                                                        Energy--All
                                                   Conti.HMS45 + - Steer
                                                  \2\ Michelin XZUS--All
                                                           Pos.
                                                 -----------------------------------------------------------------------------------------------------------------------------------------------
                 Test Method No.                                                                                Sample No.
                                                 -----------------------------------------------------------------------------------------------------------------------------------------------
                                                      1       2       3       1       2       3       1       2       3       1       2       3       1       2       3       1       2       3
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
1...............................................     47      47      47      19      21      20      30      28      33   ......  ......  ......  ......  ......  ......  ......  ......  ......
2...............................................     47      47      47      29      20      30      30      32      48      64      59      56      55    46.7      43      55      40      41
3...............................................     47      47      47       8       9       4   ......  ......  ......  ......  ......  ......  ......  ......  ......  ......  ......  ......
4...............................................     47      47      47      14      14      17   ......  ......  ......  ......  ......  ......  ......  ......  ......  ......  ......  ......
5...............................................     47      47      47       3       2       3   ......  ......  ......  ......  ......  ......  ......  ......  ......  ......  ......  ......
6...............................................     47      47      47       4       4       3   ......  ......  ......  ......  ......  ......  ......  ......  ......  ......  ......  ......
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Note: Superscript 1 represents tires tested in 2005, 2 represents tires tested in 2008.

                              Table 14--Phase II Endurance Test Results, Load Range G Bias Ply (Trailer application) and N
--------------------------------------------------------------------------------------------------------------------------------------------------------

--------------------------------------------------------------------------------------------------------------------------------------------------------

                                                                   Tire Brands (Hours Completed)
                                                         -----------------------------------------------------------------------------------------------
                                     Proposed (hours)
                                   (G-Bias) Milestar TRX
                                   (G-Bias) Milestar TRX
                                   (G-Bias) Milestar TRX
                                  (N) Prime X Rockmaster
                                 -----------------------------------------------------------------------------------------------------------------------
         Test Method No.                                                                Sample No.
                                 -----------------------------------------------------------------------------------------------------------------------
                                      1       2       3       1       2       3       1       2       3       1       2       3       1       2       3
--------------------------------------------------------------------------------------------------------------------------------------------------------
1...............................     47      47      47      71      71      71      71      71      70      71      71      64       5       6       4
2...............................     47      47      47      52      10      48      71      66      62      71      53      67   ......  ......  ......
3...............................     47      47      47      45      71      35      54      67      55       3      71      71   ......  ......  ......
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Test results also indicate that some higher load range J, L, and N
tires were overall less likely to achieve their target of 71 hours than
the load range G and H tires. Some load range J and L tires are also
used on inter-city coach buses (motorcoaches), which are operated at
highway speeds. (Tire industry data show that load range J and L tires
comprise 8 percent of the new truck tire market share (see Docket
NHTSA-2002-13707, item 18.1).) Nineteen out of the 24 (79%) load range
J tires met the proposed 47-hour test. Five out of the 9 (56%) load
range L tires tested met the proposed conditions. The load range J and
L tires we tested had speed ratings ranging from 62 to 75 mph, and all
9 tires speed-rated 75 mph met the proposed 47-hour endurance test
requirements. The agency assumes that most load range J and L tires are
speed-rated 75 mph, and that the tires would thus meet the proposed
endurance requirements. The agency is seeking comment on the percentage
of these tires that are speed-rated 75 mph.
    All of the tires were not tested to every test method for several
reasons. For load range G and H tires, the

Bridgestone and Goodyear tires were tested to Test Method 1 through
Test Method 6. The Continental D 460, Kumho 943, Kumho KRS02, and
Yokohama RY023 tires were not tested to Test Method 1 and Test Methods
3 through 6, primarily because failures from the other groups began to
surface when tested to Test Method 3. In similar fashion, tires for
load range J, L, N, and G (bias ply), were not tested once a pattern of
failures indicated that a particular test method was beginning to
result in failures for those tires.

Phase II High Speed Test

    Based on the results of the high speed tests of new tires in Phase
I,\14\ we revised the high speed test matrix for Phase II by reducing
the test speeds to speeds that are more representative of the upper
limit for heavy vehicle application. Table 15 below summarizes the test
conditions used for the high speed test in Phase II.
---------------------------------------------------------------------------

    \14\ Most failures occurred in Test Method A at test speeds of
152 km/h (95 mph) or at 160 km/h (100 mph).
[GRAPHIC] [TIFF OMITTED] TP29SE10.009

    We tested new tires of load ranges F, G, H, J, and L from several
major tire manufacturers. Test conditions varied in severity by
adjusting load, inflation pressure and/or speed. The applied load was
based on the single maximum load for the subject tire, stated on the
sidewall. The applied load ranged from 85 percent of maximum load
rating to 90 percent of maximum load rating. In Test Method (TM) C, the
least severe test method, the test load was set to 85 percent of
maximum load rating, and inflation pressure at 95 percent of maximum.
In the most severe Test Method (B), the load was set at 90 percent of
maximum load rating, and inflation at 90 percent of maximum. Inflation
pressures ranged from 90 percent to 95 percent of maximum pressure
stated on the sidewall. Generally, test speeds were 100/110/120 km/h
(62/68/75 mph). Each tire was conditioned at an ambient temperature of
35 [deg]C  3 [deg]C (95 [deg]F  5 [deg]F) for
three hours, broken in for two hours at 80 km/h (50 mph) under 88
percent of maximum load rating, and then run for duration of 2.5 hours.
The duration for the final speed step of 120 km/h (75 mph) was 1.5
hours, which represents an additional hour beyond the normal speed step
of 30 minutes.

Phase II High Speed Test Results

    Tables 16 through 24, below, summarize the results of the high-
speed test for new tires tested in Phase II, and indicate that heavy
truck tires performed well under the test matrix of Phase II. For the
138 tires tested for high-speed durability, only 10 tires failed to
meet the set target of 2.5 hours at speed. For example, the Goodyear
Drive tire samples 1, 2, and 3 (load range H) under Test Method C,
completed 2.5, 2.4 and 2.1 hours, respectively (see Table 17).
Similarly, the same tire brand completed 2.1, 2.4 and 1.9 hours under
Test Method B. Eighty-one out of the 138 tires were tested to the
proposed high speed requirements. Ninety-nine percent (80/81) met the
1.5-hour proposed requirement, Test Method D. Several

tire models from Bridgestone and Goodyear tire brands were tested first
and yielded very positive results under Test Methods C and D, which
were less severe because of the lower loading conditions. Additional
tire brands (Bridgestone, Continental, Michelin, Kumho and Yokohama)
were tested to Test Methods C and D to validate the test conditions for
use in a potential upgrade for the heavy truck tire standard.

                            Table 16--Phase II High Speed Test Results, Load Range F
----------------------------------------------------------------------------------------------------------------

----------------------------------------------------------------------------------------------------------------

                                                   Tire Brands (Hours Completed)
                                                                 -----------------------------------------------
                                              Target (hours)
                                            Goodyear 647 RSS--
                                                   Steer
                                          Michelin XRV--All Pos.
                                         -----------------------------------------------------------------------
             Test Method No.                                            Sample No.
                                         -----------------------------------------------------------------------
                                              1       2       3       1       2       3       1       2       3
----------------------------------------------------------------------------------------------------------------
D.......................................    2.5     2.5     2.5     2.5     2.5     2.5     2.5     2.5     2.5
----------------------------------------------------------------------------------------------------------------

                                                Table 17--Phase II High Speed Test Results, Load Range G
--------------------------------------------------------------------------------------------------------------------------------------------------------

--------------------------------------------------------------------------------------------------------------------------------------------------------

                                                                   Tire Brands (Hours Completed)
                                                         -----------------------------------------------------------------------------------------------
                                       Target Hours
                                    Bridgestone R293--
                                           Steer
                                   Bridgestone MIX 711--
                                           Drive
                                   General D460-- Drive
                                       Michelin XZY3
                                 -----------------------------------------------------------------------------------------------------------------------
         Test Method No.                                                                Sample No.
                                 -----------------------------------------------------------------------------------------------------------------------
                                      1       2       3       1       2       3       1       2       3       1       2       3       1       2       3
--------------------------------------------------------------------------------------------------------------------------------------------------------
A...............................    2.5     2.5     2.5     2.5     2.5     2.5     2.5     2.5     2.5   ......  ......  ......  ......  ......  ......
B...............................    2.5     2.5     2.5     2.5     2.5     2.5     2.5     2.5     2.5   ......  ......  ......  ......  ......  ......
C...............................    2.5     2.5     2.5     2.5     2.5     2.5     2.5     2.5     2.5     2.5     2.5     2.5     2.5     2.5     2.5
D...............................    2.5     2.5     2.5     2.5     2.5     2.5     2.5     2.5     2.5     2.5     2.5     2.5     2.5     2.5     2.5
--------------------------------------------------------------------------------------------------------------------------------------------------------

                                                                    Table 18--Phase II High Speed Test Results, Load Range H
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

                                                                                Tire Brands (Hours Completed)
                                                                         -----------------------------------------------------------------------------------------------------------------------
                                                       Target Hours
                                                   Goodyear G395--Steer
                                                   Goodyear G167--Drive
                                                     Kumho 943--Drive
                                                    Kumho KRS02--Drive
                                                   Yokohama RY023--Steer
                                                 -----------------------------------------------------------------------------------------------------------------------------------------------
                 Test Method No.                                                                                Sample No.
                                                 -----------------------------------------------------------------------------------------------------------------------------------------------
                                                      1       2       3       1       2       3       1       2       3       1       2       3       1       2       3       1       2       3
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
A...............................................    2.5     2.5     2.5     2.5     2.5     2.5     1.6     2.2     1.9   ......  ......  ......  ......  ......  ......  ......  ......  ......
B...............................................    2.5     2.5     2.5     2.5     2.5     2.5     2.1     2.4     1.9   ......  ......  ......  ......  ......  ......  ......  ......  ......
C...............................................    2.5     2.5     2.5     2.5     2.5     2.5     2.5     2.4     2.1     2.5     2.5     2.5     2.5     2.5     2.5     2.5     2.5     2.5
D...............................................    2.5     2.5     2.5     2.5     2.5     2.5     2.5     2.2     2.5     2.5     2.5     2.5     2.5     2.5     2.5     2.5     2.5     2.5
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

                                                Table 19--Phase II High Speed Test Results, Load Range H
--------------------------------------------------------------------------------------------------------------------------------------------------------

--------------------------------------------------------------------------------------------------------------------------------------------------------

                                                                  Group Samples (Hours Completed)
                                                         -----------------------------------------------------------------------------------------------
                                       Target Hours
                                   Goodyear Marathon LHT
                                    Bridgestone R184 CZ
                                     Bridgestone L320
                                   Yokohama TY303--Drive
                                 -----------------------------------------------------------------------------------------------------------------------
         Test Method No.                                                                Sample No.
                                 -----------------------------------------------------------------------------------------------------------------------
                                      1       2       3       1       2       3       1       2       3       1       2       3       1       2       3
--------------------------------------------------------------------------------------------------------------------------------------------------------
C...............................    2.5     2.5     2.5   ......  ......  ......  ......  ......  ......  ......  ......  ......    2.5     2.5     2.5
D...............................    2.5     2.5     2.5     2.3     2.5     1.6     2.5     2.5     2.5     1.3     1.8     1.8     2.5     2.5     2.5
--------------------------------------------------------------------------------------------------------------------------------------------------------

                                                Table 20--Phase II High Speed Test Results, Load Range J
--------------------------------------------------------------------------------------------------------------------------------------------------------

--------------------------------------------------------------------------------------------------------------------------------------------------------

                                                                               Tire Brands (Hours Completed)
                                                                                -----------------------------------------------------------------------
                                                              Target (hours)
                                                             Goodyear Unisteel
                                                              G291--All Pos.
                                                           Yokohama RY253 (wb)--
                                                                 All Pos.
                                                           Michelin XZY3 (wb)--
                                                                 All Pos.
                                                         -----------------------------------------------------------------------------------------------
                     Test Method No.                                                                Sample No.
                                                         -----------------------------------------------------------------------------------------------
                                                              1       2       3       1       2       3       1       2       3       1       2       3
--------------------------------------------------------------------------------------------------------------------------------------------------------
D.......................................................    2.5     2.5     2.5     2.5     2.5     2.5     2.5     2.5     2.5     2.5     2.5     2.5
--------------------------------------------------------------------------------------------------------------------------------------------------------

                            Table 21--Phase II High Speed Test Results, Load Range J
----------------------------------------------------------------------------------------------------------------

----------------------------------------------------------------------------------------------------------------
                                               Target Hours
                                                   Tire Brands (Hours Completed)
                                                                 -----------------------------------------------

                                               Michelin XTA
                                                Kumho KRT02
                                         -----------------------------------------------------------------------
             Test Method No.                                            Sample No.
                                         -----------------------------------------------------------------------
                                              1       2       3       1       2       3       1       2       3
----------------------------------------------------------------------------------------------------------------
D.......................................    2.5     2.5     2.5     2.5     2.5     2.5     2.3     2.5     2.5
----------------------------------------------------------------------------------------------------------------

                                                Table 22--Phase II High Speed Test Results, Load Range L
--------------------------------------------------------------------------------------------------------------------------------------------------------

--------------------------------------------------------------------------------------------------------------------------------------------------------

                                                                               Tire Brands (Hours Completed)
                                                                                -----------------------------------------------------------------------
                                                               Target Hours
                                                            Continental HMS 45+
                                                            Michelin XZUS--All
                                                                   Pos.
                                                          Michelin XZA2 Energy--
                                                                 All Pos.
                                                         -----------------------------------------------------------------------------------------------
                     Test Method No.                                                                Sample No.
                                                         -----------------------------------------------------------------------------------------------
                                                              1       2       3       1       2       3       1       2       3       1       2       3
--------------------------------------------------------------------------------------------------------------------------------------------------------
D.......................................................    2.5     2.5     2.5     2.5     2.5     2.5     2.5    2.25     2.5     2.5     2.5     2.5
--------------------------------------------------------------------------------------------------------------------------------------------------------

                                       Table 23--Phase II High Speed Test Results, Load Range J, no break-in step
--------------------------------------------------------------------------------------------------------------------------------------------------------

--------------------------------------------------------------------------------------------------------------------------------------------------------

                                                                               Tire Brands (Hours Completed)
                                                                                -----------------------------------------------------------------------
                                                              Target (hours)
                                                           Michelin XZY3 (wb)--
                                                                 All Pos.
                                                             Goodyear Unisteel
                                                              G291--All Pos.
                                                           Yokohama RY253 (wb)--
                                                                 All Pos.
                                                         -----------------------------------------------------------------------------------------------
                     Test Method No.                                                                Sample No.
                                                         -----------------------------------------------------------------------------------------------
                                                              1       2       3       1       2       3       1       2       3       1       2       3
--------------------------------------------------------------------------------------------------------------------------------------------------------
D.......................................................    2.5     2.5     2.5     2.5     2.5     2.5     1.5    2. 5     2.5     2.5     2.5     2.5
--------------------------------------------------------------------------------------------------------------------------------------------------------

                   Table 24--Phase II High Speed Test Results, Load Range L, no break-in step
----------------------------------------------------------------------------------------------------------------

----------------------------------------------------------------------------------------------------------------

                                                   Tire Brands (Hours Completed)
                                                                 -----------------------------------------------
                                              Target (hours)
                                            Michelin XZUS--All
                                                   Pos.
                                          Michelin XZA2 Energy--
                                                 All Pos.
                                         -----------------------------------------------------------------------
             Test Method No.                                            Sample No.
                                         -----------------------------------------------------------------------
                                              1       2       3       1       2       3       1       2       3
----------------------------------------------------------------------------------------------------------------
D.......................................    2.5     2.5     2.5    2.15     2.5     2.3     2.5     2.5     2.5
----------------------------------------------------------------------------------------------------------------

b. Summary
    The results of the endurance and high speed tests indicated that
the test requirements of FMVSS No. 119 can be upgraded for radial tires
to specify more stringent, yet practicable, levels of performance that
ensure better durability in real-world applications.
    Based on these test results, NHTSA proposes to upgrade the
endurance performance requirement and establish a new high-speed
performance requirement for radial tires of load ranges F, G, H, J, and
L, that are not for speed-restricted service, which comprise about 98
percent of the truck

tires sold in the United States.\15\ These tires are typically used for
regional haul and long haul operations and on motorcoaches. The
remaining 2 percent represent the higher load rating tires and bias ply
tires, which are more often used in mixed service (on/off-road
operations in lower speed applications), such as construction, logging,
crane, and rigging operations. However, the agency is also considering
requiring non-speed-restricted, load range M radial tires to comply
with the upgraded endurance and new high speed tests because some of
these tires are used in similar applications as load range L tires. The
agency is not proposing any new requirements for load range N tires,
which represent less than 1 percent of new tires sold and are typically
used in lower speed operations. The agency is also not proposing any
new requirements for bias ply tires, primarily because they are
typically not installed on new heavy vehicles and they represent a very
small portion of the tires sold as replacement tires. These tires would
continue to be required to comply with the current requirements. In
addition, the agency is not proposing updated requirements for light
truck tires with tread depth \18/32\ inch or greater or for speed-
restricted tires; these tires, used on light truck applications, are
load range E category, and are not the focus of this rulemaking. The
agency is not proposing any new requirements for bias ply tires,
primarily because we are not aware that they are installed on new heavy
vehicles, and we aimed at upgrading radial tires, which represent the
vast majority of the tires used on heavy vehicles.
---------------------------------------------------------------------------

    \15\ New truck tire market share by load range is as follows: F-
5 percent, G-64 percent, H-23 percent, J-3 percent, L-5 percent, M
and N is less than 1 percent. See Docket NHTSA-2002-13707, item
18.1.
---------------------------------------------------------------------------

IV. Proposed Endurance Test

    NHTSA is proposing to upgrade FMVSS No. 119's requirements for load
ranges F, G, H, J, and L tires that are not for speed-restricted
service by setting more stringent requirements for the endurance test.
NHTSA proposes that the endurance test be conducted using the
parameters shown in Table 25. The proposed and current endurance test
parameters may be compared as shown in Tables 25 and 26 below:

                           Table 25--Proposed FMVSS No. 119 Endurance Test Conditions
----------------------------------------------------------------------------------------------------------------
                                                                                Inflation
                  Load ranges                       Steps       Load  (%     Duration   Speed  (km/    pressure
                                                                  max)        (hrs)          h)        (% max)
----------------------------------------------------------------------------------------------------------------
                                                           1           85            7  ...........  ...........
F, G, H, J, and L..............................            2           90           16           80           80
                                                           3          100           24  ...........  ...........
----------------------------------------------------------------------------------------------------------------

                            Table 26--Current FMVSS No. 119 Endurance Test Conditions
----------------------------------------------------------------------------------------------------------------
                                                                                Load (% max)
                                                                   Inflation -----------------------------------
                     Load ranges                      Speed  (km/  pressure             Duration (hrs)
                                                          h)        (% max)  -----------------------------------
                                                                                7          16          24
----------------------------------------------------------------------------------------------------------------
F...................................................          64  ..........  ..........  ..........  ..........
G...................................................          56         100          66          84         101
H, J, L, M, N.......................................          48  ..........  ..........  ..........  ..........
----------------------------------------------------------------------------------------------------------------

    A tire would comply with the proposed requirements if, at the end
of the endurance test as currently defined by the standard, there is no
visual evidence of tread, sidewall, ply, cord, inner liner, belt or
bead separation, chunking, open splices, cracking or broken cords, and
the tire pressure, when measured at any time between 15 and 25 minutes
after the end of the test, is not less than 95% of the initial test
pressure.

a. Test Speed

    NHTSA proposes to raise the test speed for the endurance test to 80
km/h (50 mph) for load range F, G, H, J, and L tires, which are not for
speed-restricted service. This represents a 25 percent increase in
speed for a load range F tire, a 43 percent increase for a load range G
tire, and a 67 percent increase for load range H, J, and L tires. It is
noted that these tests are performed on a curved road wheel, a 67-inch
diameter steel drum, on which the tire being tested runs as on a
treadmill. Because the road wheel is curved, it subjects the tire to
reverse deflection compared to a tire running on a flat surface, which
makes the tire run hotter (and is therefore a more severe test).
According to American Society for Testing and Materials International
(ASTM International) research on equivalent flat-to-curved speeds based
on equivalent belt-edge temperatures, a load range G truck tire tested
on a 67-inch diameter road wheel at 85 km/h (53 mph) experiences belt-
edge temperatures similar to what a tire experiences when tested on a
flat road surface at 120 km/h (75 mph). Thus, it was determined that
the effects on the tire in the two situations will be similar, even
though the one tire is rotating at 85 km/h (53 mph) and the other at
120 km/h (75 mph). (``Phase 1--Final Report,'' ASTM Truck/Bus Tire Test
Development Task Group, 9/5/06, Docket No. NHTSA-2002-13707-10.)
    In NHTSA's Phase II testing, tires were tested to speeds of 80, 90,
and 100 km/h (50, 56, and 62 mph) as potential upgrades to the current
test speeds. Only 3 of 30 tire samples were able to complete a 71-hour,
or even a 47-hour test, at 100 km/h (62 mph). At 90 km/h (56 mph), all
except three of the load range G and H tires were able to complete 47
hours. At 80 km/h (50 mph), all of the load range F, G and H tires
completed the 71-hour test without failure, even at 80 percent
inflation. Load range J tires had mixed results, and for load range L
tires, only 7 of 21 tires tested were able to complete 47 hours of the
endurance test.
    Given these results, NHTSA believes that a speed of 80 km/h (50
mph) for the endurance test, when coupled with the inflation pressure
and load parameters

we are proposing, represents a substantial and realistic upgrade over
current requirements for commercial vehicle tires. In selecting this
test speed, we considered the maximum speed rating of the tires we
tested and those typically used in commercial vehicle applications,
including motorcoaches, and found that, according to tire manufacturer
catalogs,\16\ the majority of the tires in these usage categories were
rated at 120 km/h (75 mph). All the test tires that were rated at 120
km/h (75 mph) and some that were rated at 110 km/h (68 mph) or lower
completed the proposed 47-hour Endurance test without failure. Even
though load range J and L tires comprise only about 6 percent of the
commercial vehicle tire market, NHTSA is aware that load range J and L
tires are used on some commercial inter-city coach buses
(motorcoaches), operated on interstate highways, and their use as such
highlights the need to propose upgrading the endurance test speed for
these tires. The agency is aware that while some load range J and L
tires are rated at a maximum speed of 120 km/h (75 mph), many others
are rated at speeds between 88 km/h (55 mph) and 110 km/h (68 mph). As
a result, the agency solicits comment on the appropriateness of the 80
km/h (50 mph) test speed for load range F, G, H, J, and L tires in the
endurance test.
---------------------------------------------------------------------------

    \16\ Tire catalogs were found online (www._) at manufacturer
Web sites.
---------------------------------------------------------------------------

    The agency is also considering requiring non-speed-restricted, load
range M radial tires to comply with the upgraded endurance test because
some of these wide base tires may be used in similar applications that
load range L tires are used. Given that the maximum speed rating of
these tires allows them to be used in high speed operations, possibly
instead of two lower load range tires, the agency believes that they
should be considered for inclusion in the upgrade since they could be
used in different vehicle applications than the typical speed-
restricted, load range M radial tires. Accordingly, the agency solicits
comment on requiring non-speed-restricted, load range M radial tires to
comply with the upgraded endurance test.
    We are unaware of non-speed restricted, radial, load range N tires
being used in high speed operations, thus we are not proposing that
they be required to comply with this upgrade. NHTSA does not propose to
raise the endurance test speed for non-speed-restricted, load range N
tires from 48 km/h (30 mph), given their typical use on heavy vehicles,
and our concern that increasing the speed would not be practicable. Due
to their design and typical application to heavy vehicles used in mixed
(on/off-road) service at slow speeds, load range N tires performed
poorly even at the lowest test speed used by NHTSA. As stated
previously, these tires make up about 1 percent of the total market for
truck tires. NHTSA believes there is no demonstrated safety need to
upgrade these tires to comply with a more stringent endurance test,
given the typical uses of the tires.

b. Load

    NHTSA proposes to change the load combination for the endurance
test to 85, 90, and 100 percent of the tire's maximum load rating, from
the 66, 84, and 101 percent combination currently required. NHTSA's
Phase II testing specified test loads at 85, 90, and 100 percent for
the same durations as currently required in FMVSS No. 119. Increasing
the first two load steps from 66 and 84 percent increased the
stringency of the first 23 hours of the proposed test, and makes them
consistent with the loads specified in FMVSS No. 139's endurance test
for light vehicle tires. NHTSA believes increasing the test load
combination from 66, 84, 101 percent to 85, 90, and 100 percent of the
tire's maximum load rating represents an overall upgrade of the loading
condition for FMVSS No. 119.
    Tire failure on a vehicle in service can occur due to under-
inflation or overloading, or both. Heavy vehicle tires are used
predominantly on commercial vehicles, such as transit buses, tractor
trailer combination vehicles, and ready-mix concrete trucks, for which
loading to the vehicle's gross vehicle weight rating is typical of
normal use. Non-commercial heavy vehicles such as recreational vehicles
(motor homes) and school buses also use truck tires. Unlike passenger
cars and other light vehicles, which are rarely loaded to their maximum
vehicle weight, heavy vehicles are often used in commercial service
where the vehicle is loaded to its rated cargo or passenger load to
maximize the profitability of the vehicle's operation. Hence, the first
two steps of the proposed endurance test reflect the tire's performance
conditions at which it is expected to be used in normal service.

c. Inflation Pressure

    NHTSA proposes to set inflation pressure at 80 percent of the
sidewall-labeled inflation pressure that corresponds to the tire's
maximum load rating. This represents a 20 percent decrease from the
current endurance test, which requires tires to be fully inflated. Data
from a tire pressure survey conducted by FMCSA suggests that tires on
commercial vehicles (particularly trailers) are often run under-
inflated by at least 140 kPa (20 psi).\17\ For a load range G tire,
which has a maximum inflation pressure of 760 kPa (110 psi), this level
of under-inflation represents roughly an 18 percent loss of inflation
pressure. NHTSA believes that conducting the endurance test at some
level of under-inflation instead of fully inflated better reflects
real-world conditions. NHTSA testing found that all load range G and H
tires were able to complete the endurance test at an inflation of 80
percent of maximum, even at 80 km/h (50 mph).\18\ Load range J tires,
which have a higher maximum load rating than load range G and H tires,
showed mixed results, while higher load range L and N tires experienced
failure rates at both the 90 percent and 80 percent levels of
inflation.
---------------------------------------------------------------------------

    \17\ The FMCSA study, ``Commercial Vehicle Tire Condition
Sensors'' (Federal Motor Carrier Safety Administration, Nov. 2003),
looked at a total of 6,087 units and 35,128 tire samples and found,
among other things, that approximately 7 percent of the sampled
heavy vehicles have at least one tire under-inflated by 20 psi or
more.
    \18\ We also note that at higher test speeds, tire performance
appears noticeably sensitive to inflation pressures. At 100 km/h,
more failures occurred at the 80 percent inflation level, and time
to failure was also shorter at that inflation level compared to 100
percent inflation.
---------------------------------------------------------------------------

    NHTSA believes that testing at this level of under-inflation
represents an appropriate upgrade of the severity of the endurance test
for load range F through L truck tires. We note that the endurance
tests in the light vehicle tire standards, FMVSS Nos. 109 and 139, are
conducted with the tire under-inflated to 25 percent below its maximum
inflation pressure. NHTSA is aware that the tire industry considers 20
percent under-inflation to be essentially flat for truck tires, which
are designed to run close to their maximum inflation.

d. Duration

    NHTSA proposes not to amend FMVSS No. 119's endurance test duration
of 47 hours. The current 47-hour test at 56 km/h (35 mph) results in a
distance traveled for a load range G tire of 2,632 km (1,645 miles),
and increasing the speed to 80 km/h (50 mph) increases the traveled
distance to 3,760 km (2,350 miles), a 43 percent increase in distance.
NHTSA's Phase II testing extended the endurance test duration to 71
hours so researchers could assess how long beyond the 47-hour duration
the tires were able to

perform. Because the failure rate did not change significantly in
testing tires beyond 47 hours,\19\ this indicates that the tires'
performance to the endurance test is less sensitive to changes in
duration than to changes in speed and inflation pressure. Thus, we
believe that extending the duration beyond the 47 hours already
required will not provide additional performance benefits.
---------------------------------------------------------------------------

    \19\ When a tire failed, it generally failed well before 47
hours, rather than completing the 47 hours and then failing.
---------------------------------------------------------------------------

e. Ambient Temperature

    NHTSA proposes to add a 3 [deg]C (5 [deg]F)
tolerance to the current ambient temperature specified for FMVSS No.
119's endurance test, 35 [deg]C (95 [deg]F). Tire test laboratories
benefit from an ambient temperature tolerance. The proposed 3 [deg]C (5 [deg]F) tolerance for the ambient
temperature is consistent with FMVSS No. 109 and FMVSS No. 139 in
providing a 3 [deg]C (5 [deg]F) tolerance
needed to facilitate the operations at the tire laboratories.\20\
---------------------------------------------------------------------------

    \20\ In FMVSS No. 139, NHTSA requires an ambient temperature for
road-wheel testing of not less than 32 [deg]C and not more than 38
[deg]C.
---------------------------------------------------------------------------

f. Endurance Test Conclusions

    The agency tentatively concludes that the proposed requirements for
the endurance test better reflect the reality of tire usage than the
current FMVSS No. 119 requirements. The proposed parameters for the
endurance test, particularly the increased test speed and the reduced
inflation pressure, reflect conditions that a heavy vehicle tire is
more likely to experience in normal service.
    Based on research performed by the ASTM, a tire operated at a
highway speed of 120 km/h (75 mph) experiences an equivalent level of
stringency when tested at 85 km/h (53 mph) on a curved test wheel.\21\
We believe that the agency's proposed endurance test speed of 80 km/h
(50 mph) on the curved test wheel is therefore a realistic speed.
---------------------------------------------------------------------------

    \21\ ASTM Truck/Bus Tire Test Development Task Group, Phase I--
Final Report, September 7, 2006. Available at Docket No. NHTSA-2002-
13707, Item 10.
---------------------------------------------------------------------------

    The proposed inflation pressure for the endurance test is 80
percent of the maximum sidewall pressure, compared with 100 percent
currently specified in FMVSS No. 119. According to the results of
FMCSA's tire pressure monitoring survey cited above, on 6,087 heavy
vehicle units with over 35,000 tires sampled, approximately 20 percent
of the vehicles had at least one tire that was under-inflated by 20 psi
or more. As a result, testing with some level of under-inflation
reflects the reality of what heavy truck tires typically experience in
service.
    The agency's testing to the proposed endurance test showed that 85
percent of all the load range F, G, H, J, and L tires tested completed
the 47-hour portion of the test, with the load range J and L tires
speed-rated less than 75 mph comprising 11 out of 12 of the failures
under 47 hours. All the load range G and H tires tested completed the
47-hour portion of the test without any failures. However, even though
the load range G and H tires met the proposed requirements when tested
for a duration of 47 hours, NHTSA expects that some manufacturers of
load range G and H tires may make some design changes to these tires to
maintain an adequate margin of compliance. We expect that design
changes will be needed for some load range J and L tires, particularly
those with a maximum speed rating lower than 120 km/h (75 mph), to
enable them to comply with the proposed Endurance test requirements at
80 km/h (50 mph). The agency seeks comments on the appropriateness of
the proposed endurance test parameters for these tires.

V. Proposed High Speed Test

    In its tire testing program, NHTSA performed high speed tests on
load range F, G and H tires because these are the ones predominantly
used on commercial vehicles and are the most likely of all higher load
range tires to be operated at the speed conditions proposed for this
test. NHTSA performed high speed tests on load range J and L tires even
though the tires have a small market share (about 8 percent), because
some of these tires have a maximum speed rating of 75 mph and are used
on motorcoaches.\22\ NHTSA did not perform high speed tests on speed-
restricted load range M or N tires, because we were aware that these
tires are not typically operated at these speed conditions. After
careful review of the testing results and of the information on the use
of load range J and L tires on coach buses, NHTSA proposes to include
in FMVSS No. 119 a high speed test for load range F, G, H, J, and L
tires, that are not for speed-restricted service. In addition, the
agency is also considering requiring non-speed-restricted, load range M
radial tires to comply with the upgraded endurance and new high speed
tests because some of these tires are used in high speed operations.
Bias ply and load range N tires that are for speed restricted-service
would not be subjected to a high speed test.
---------------------------------------------------------------------------

    \22\ The same size tire can become a load range G, H, or J tire
depending on its construction and on its inflation pressure (e.g.,
for a 315/80R22.5 tire, the maximum load rating (3,750 kg or 8,270
lbs) for the load range J tire is achieved at an inflation pressure
of 830 kPa (120 psi), and the maximum load rating (3,450 kg or 7,610
lbs) when used in the load range H application is achieved at an
inflation pressure of 760 kPa (110 psi)). A comparison of the load/
inflation pressure values in the 2007 Tire and Rim Association Year
Book for the proposed high-speed test conditions (85 percent of
maximum load rating, 90 percent of maximum inflation pressure)
indicates that the tires are well within the load limits specified
for the test inflation pressure. For the tire size example used
above, the test load for a load range J tire would be 3,188 kg or
7,030 lbs (85 percent of maximum load rating) and the test inflation
pressure would be 747 kPa (108 psi), which is well above the
inflation pressure of 670 kPa needed to support that test load
according to the Year Book.
---------------------------------------------------------------------------

    NHTSA proposes that the high speed test would be initiated after a
2-hour break-in at 80 km/h (50 mph) and 85 percent of maximum load
rating, with inflation pressure at 90 percent of maximum. The break-in
procedure conditions a new tire for testing since it exercises the tire
components and increases the tire temperature, which results in some
growth in the rubber components of the tire. This tire growth results
in a slight decrease in the tire's inflation pressure at the end of the
break-in period and leads to less growth and negligible pressure
decrease at the end of the 90-minute high speed test.
    There is currently a high speed test in FMVSS No. 119, but it
applies only to motorcycle tires and to non-speed-restricted tires with
a rim diameter code of 14.5 or less marked load range A, B, C, or D.
Therefore, heavy vehicle tires with a load range of F or above have not
been required to meet the high speed test requirements in the current
standard. Table 22 shows test parameters for the proposed high speed
test.

                                       Table 27-High Speed Test Conditions
----------------------------------------------------------------------------------------------------------------
                                                                                Inflation
                     Load ranges                         Steps    Speed  (km/  Duration    Load  (%    pressure
                                                                      h)       (minutes)     max)       (% max)
----------------------------------------------------------------------------------------------------------------
                                                        Break-in          80         120          85          90
F, G, H, J, and L...................................           1     Max--20          30  ..........  ..........
                                                               2     Max--10          30          85          90
                                                               3         Max          30  ..........  ..........
----------------------------------------------------------------------------------------------------------------

    A tire would comply with the proposed requirements if, at the end
of the high speed test, there is no visual evidence of tread, sidewall,
ply, cord, inner liner, or bead separation, chunking, open splices,
cracking, or broken cords,\23\ and the tire pressure, when measured at
any time between 15 and 25 minutes after the end of the test, must not
be less than 95% of the initial test pressure. Load range M tires are
not included in the high speed test table but the agency seeks comments
on whether those non-speed-restricted, radial tires, should be required
to comply with the new proposed high speed test requirements. We are
unaware of non-speed restricted, radial, load range N tires being used
in high speed operations, thus we tentatively conclude that they not be
required to comply with this upgrade.
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    \23\ We note that all of these terms are defined in the current
standard.
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a. Test Speed and Break-In Procedure

    NHTSA proposes to set the test speed for the high-speed test at the
tire's maximum speed less 20 km/h (12 mph) for step 1, maximum speed
less 10 km/h (6 mph) for step 2, and at maximum speed for the final
step. This approach is similar to the approach used by the United
Nations Economic Commission for Europe (ECE) tire Regulations, which
establish tire test speeds based on the maximum rated speed of the
tire. It is also consistent with RMA's suggestion to the agency that
tires should only be tested for high speed performance up to their
maximum speed rating.\24\ We are proposing this approach, instead of
establishing one set of test speeds as a minimum requirement for all
tires as we have done for motorcycle and passenger car tires, because
unlike motorcycle and passenger car tires, heavy vehicle tires are
designed for a wide range of applications and have a narrow range of
maximum speed ratings.
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    \24\ Docket No. NHTSA 2002-13707-0016.1.
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    The truck tires for which we are proposing a high speed test in
FMVSS No. 119 have speed ratings ranging only from 100-120 km/h (62-75
mph), which are typical operating speeds for the heavy vehicles on
which these tires are installed. If one set of test speeds were applied
to these tires regardless of the speed rating, a tire speed rated at
the lower end of the range could be subjected to test speeds above the
speed rating of the tire, which could be inappropriate. (An example of
this situation is a tire speed rated to 62 mph tested at a speed of 75
mph.) Conversely, subjecting a tire that is speed rated at the higher
end of the range to a test speed substantially below the speed rating
of the tire might under-test the tire and fail to evaluate its high
speed performance. Therefore, we are proposing to establish test speeds
based on the tire's speed rating because we believe that it results in
a high speed test that better reflects the limits of the tire's
performance.
    However, we disagree with RMA's suggestion that the high speed test
procedure should exclude the break-in step, which is normally the first
step when conducting a high speed test. The regulatory text of this
NPRM does not remove the break-in step from the procedure but we are
soliciting comments on whether it is appropriate to do so. The agency's
tire testing included a break-in step and we plan to gather additional
data on tires tested without the break-in step to determine whether
there is a difference in the tire's performance.
    We have tentatively decided to retain the break-in step because the
step helps to condition the rubber components of new tires through
initial flexing that allows the tire to expand and grow prior to
testing. As a result, tire growth is minimized during the test, which
in turn minimizes the decrease of the test pressure at the end of the
test. Further, the high speed test for light vehicle tires has a break-
in step. When we issued the upgraded light vehicle tire standard in
2003, the agency included the tire break-in procedure in FMVSS No.