If you’re even a casual bowler who heads to the bowling lanes once in a great while, you’ve still probably asked yourself a common question – what are bowling balls made of exactly? Bowling balls may seem simple from an outsider’s perspective, but they are far from it. In fact, they’ve evolved a great deal over the years into a tactile form of high technology! 

They may not have exactly started off that way, but bowling balls have been tempered by years of trial and error, technological advancements to the game, and ultimately technological advancements to the composition of the bowling ball itself. So, what are bowling balls made of? We’ll need a bit of historical framing to answer that question adequately and correctly.

The History Of Bowling Ball Material

The sport of bowling has been around for thousands upon thousands of years in two distinct forms, lawn bowling and pin bowling. How long bowling has been around is a source of conjecture, but a recent grave exhumation of an Egyptian child buried over 5,000 years ago uncovered a set of stone pins assumed to have been used for a form of bowling.

The majority of the first known bowling balls for both lawn bowling and pin bowling were made of Lignum vitae, an extremely hard wood. Wood bowling balls were used during the heyday of ninepin bowling in the 1800s – a form of bowling which was eventually banned in Connecticut and New York due to its blanket association with illegal gambling rings.

To circumvent this law against ninepin bowling, bowling lane operators added a tenth pin and created the game as we know it today. At this time, hard wood bowling balls were still the ball of choice for bowlers around the United States and the world in general.

Come 1905, the first rubber bowling was produced. The Evertrue was a solid hit, but it wasn’t until Brunswick entered the fold in 1914 with their ball made of a “mysterious rubber compound” that the rubber bowling ball really took off worldwide. 

Brunswick put a ton of advertising dollars into making sure their new Mineralite bowling ball was the talk of the budding bowling world, sending Mineralite bowling balls to YMCAs around the United States so that potential consumers could try out the new technological breakthrough.

Rubber bowling balls were a massive success as bowling continued to gain a foothold with the casual consumer. These early bowling balls had no true core design to them. Instead, they usually contained light density inner-fillers at the center of the ball, along with a weight block near the ball’s surface which could be tweaked in its layout to modify a ball’s preferred lane path.

The rubber bowling ball’s death knell came a decade or two after the development of the plastic/polyester bowling ball in 1959. The last commercially successful rubber bowling ball was the Brunswick LT-48, introduced in the 1970s before losing its market share as the 1980s went on.

The plastic/polyester bowling ball is the first of the currently-used bowling balls trafficked around and down bowling alleys to this very day. And it’s a great starting point for answering the question of what a modern day bowling ball is made of.

Modern Day Bowling Ball Material

Modern day bowling balls have evolved from their polyester/plastic bowling ball roots, although plastic bowling balls are still widely used by children, beginners, and as the go-to option for many as a straight-line spare bowling ball. 

However, plastic bowling balls’ inefficiency in reacting to lane conditions proved troubling after the plastic bowling ball replaced the rubber bowling ball as the ball of choice on the Professional Bowlers’ Association tour in the 1970s. 

Because there wasn’t enough friction generated by these balls in relation to the oil on a modern bowling lane, serious bowlers lamented their tendency to skid down the lane and their lack of back-end action snapping into the pin pocket.

This problem was solved indirectly in the 1980s as urethane-based lane finishes became ubiquitous due to their relatively cost-effective nature. In response, urethane bowling balls with softer cover stocks and more porous natures hit the market with a flourish. 

These bowling balls reacted much better than polyester bowling balls to lane conditions, giving bowlers a better overall hook potential despite requiring much more general maintenance after repeated use gummed up the ball’s pores with lane oil and reduced its overall effectiveness.

Urethane bowling balls are still widely used to this day, and they’re also the general base for the newest and most popular modern-day bowling ball advancement – the reactive resin bowling ball. 

These, along with particle cover stock bowling balls, began the wave of aggressive new bowling ball cover stocks built heavily porous and friction-heavy to react heavily to lane conditions and allow experienced bowlers to maximize their shots and ability to read lane conditions to increase hook violence and overall pin carry.

Reactive resin bowling balls are the strike bowling ball of choice for professional bowlers and league bowlers around the world, combining constantly-evolving cover stock technology with multiple different internal core types and outlays (more on that later) to create a new type of bowling ball which maximizes lane reaction to increase scores and the effectiveness of intricate bowler shot patterns.

Bowling Balls For Different Types Of Bowling

The technological evolution of bowling balls detailed above has happened in concurrent fashion across the many variations of bowling played across the world landscape. 

Some of the above composition advancements have carried over into niche bowling styles around the globe, while some bowling game variations have their own unique bowling ball compositions (and evolution of said compositions) to speak of.

Ten Pin Bowling

Our previous analysis of the modern-day bowling ball’s many different iterations and forms is generally an analysis of ten pin bowling balls as a whole. 

Ten pin bowling accounts for the vast majority of bowling alleys around the United States and the world, with bowling balls of varying cover stocks (plastic, urethane, reactive resin, particle) usually drilled with three different finger holes for placing the thumb, middle finger and ring finger.

The cover stock composition material functions as both the friction generator with the different oil patterns of the modern ten pin bowling lane, and it functions as the buffer which protects the core of the bowling ball (more on what the core of the bowling ball does, and is, later).

The majority of bowling balls used in ten pin bowling at the highest levels are made of some sort of reactive resin cover stock technology. However, plastic, urethane, and particle bowling balls are also omnipresent at most bowling alleys around the country and the world.

Five Pin Bowling

Five pin bowling still has a major footprint all over Canada, with five pin bowling lanes proliferating the landscape in every Canadian province. 

A five pin bowling ball is usually made of a rubber/synthetic hybrid at a ratio of four to one or greater. These bowling balls are, for the most part, created without finger holes and are about the size of the average adult hand.

Five pin bowling was created in Toronto back in 1909 as a direct response to bowling consumers who felt the normal ten pin game was too stressful and required too much of a physical investment. 

The only true regulation for five pin bowling balls is that there cannot be a metallic component to the bowling ball, leading some of the cover stock and synthetic composition elements of ten pin bowling balls into the technology for some modern five pin bowling balls. However, rubber bowling balls remain the general name of the game for this Canadian specialty.

Duckpin Bowling

A duckpin bowling ball follows the exact same weight and sizing specifications of a five pin bowling ball, and are usually made of a similar rubber/synthetic hybrid to that of their five pin counterparts – also usually without finger holes.

In fact, many bowling balls made for the squat ten duckpin setup find their way into five pin bowling alleys north of the border, and vice versa.

Duckpin bowling alleys can be found in several states in the Northeastern United States, although the amount of duckpin bowling alleys has dwindled considerably since the sport’s heyday in the early 20th Century.

All duckpin (and five pin) bowling balls must be between 4.75 inches and 5 inches in diameter, and they must weigh between 3 pounds 6 ounces and 3 pounds 12 ounces. About the size of a regulation softball, duckpin bowling balls have diameters which are over 60% smaller than that of a regulation ten pin bowling ball.

These duckpin bowling balls can also be found at arcades and entertainment centers around the United States and the world where a miniature ten pin bowling game is present.

Candlepin Bowling

Candlepin bowling is an extremely unique variation of bowling where the bowling ball is actually  lighter than each of the ten thin, candle-esque pins placed at the end of the alley!

Played primarily in the Northeastern United States and Canadian maritime provinces, candlepin bowling balls are allowed to be made of wood, rubber, plastic, or a hybrid of these materials. 

Candlepin bowling balls are allowed to have a weight between 2 pounds 4 ounces and 2 pounds 7 ounces, and are .5 inches smaller in diameter (4.5 inches) than that of a duckpin/five pin bowling ball! These, of course, usually have no finger holes.

If you ever play candlepin bowling, you’ll notice two things. Firstly, the ball deflects off the pins hard because candlepins are 2 pounds 8 ounces – heavier than the heaviest candlepin bowling ball. 

Secondly, a candlepin bowling ball is small enough to be thrown between pins set up in the same row. This makes it much harder to find a pocket and generate pin carry!

What’s Inside Of The Bowling Ball?

For the purpose of this section, we’re going to move back to the world of ten pin bowling – the most widely played version of the sport we know and love!

A ten pin bowling ball generally has a three-part construction to it – the outside cover stock, an outer core made of “filler” material, and a hardened inner core.

While each different bowling ball company’s specific list of materials for the construction of its products are considered “proprietary technologies that are closely guarded,” there are some general composition elements for both the outer and inner cores of a bowling ball.

A bowling ball’s outer core is lighter than its inner core, and it usually is composed of a filler material which utilizes multiple different types of substances such as polyester and glass beads. It’s this part of the bowling ball which is tweaked by a manufacturer in order to finalize a bowling ball’s overall weight and density ratio.

As for a bowling ball’s inner core, it’s often made up of powdered metal oxides mixed with resin and a chemical catalyst to harden the entirety of the core to an almost-metal state. These cores can be shaped in a variety of different ways. Some are shaped like a pancake, some are symmetrically spherical, and some are intentionally imbalanced (such as a lightbulb-shaped core).
Each different core shape has different effects on hook potential and straight-line efficacy, with a symmetrical core tending to hook much less (and with much less sharpness) than its asymmetrical counterparts.

What Does A Bowling Ball Cover Stock Do?

A bowling ball’s cover stock is the most important part of the ball’s overall performance, by far! In fact, a bowling ball’s cover stock is responsible for anywhere from 60% to 80% of a ball’s performance on the lanes, with the rest being attributed to the different core structures and mass/density ratios of the ball’s inner and outer core structure. 

A bowling ball cover stock is the part of the bowling ball which actually makes contact with the lanes. Therefore, it’s the main generator of needed friction (or in the case of a plastic spare bowling ball, the main means for reducing friction) to give a bowler’s shot needed power, snap and overall hook potential.

High-performance bowling balls made with polyurethane, reactive resin cover stocks are also made porous to absorb lane oil in such a way that the ball truly reacts in accordance with the lane’s oil patterns. This reactivity is crucial for the intermediate or advanced bowler who wants to refine and sharpen their hooks, and add power/violence to their overall back-end reaction and pin carry.

In short, a bowling ball cover stock does most of the work because it’s the part which carries out the plan of action for the ball on the lanes!

Do Bowling Balls Float?

It depends on the weight of the bowling ball! Each different weight of bowling ball has a different density, with a regulation 12-pound bowling ball being the closest in density (0.99 grams/centimeters cubed) to that of water (1 gram/centimeter cubed).

Therefore, a regulation bowling ball which is 12 pounds or lighter will float in water if it hasn’t been modified in any way! Balls that are 13 pounds or heavier will sink because their overall density is greater than that of water.

Do Bowling Balls Go Bad? 

Bowling balls don’t spoil, but they do have a shelf life. If you clean your bowling ball regularly and do all the needed routine maintenance on it, there is a very good chance that your bowling ball will maintain efficacy and overall quality for a period of five to ten years

The two main worries for your bowling ball’s overall longevity is the condition of the cover stock and the condition of the ball’s core. The problem with modern high-performance bowling balls is that they are built with cover stocks that are porous and softer than older bowling balls for the purpose of lane reactivity.

This is all well and good when a bowling ball is in good shape, but it also can lead to an improperly-maintained bowling ball cover stock cracking or chipping over time. And in fact, this could happen anyways with a case of bad luck. 

A cracked bowling ball cover stock is essentially the death knell for a bowling ball, as is a potential core separation. If a bowling ball core comes apart or loses its stationary place in the depths of your bowling ball, it can completely throw your ball off balance and turn it into nothing more than an overpriced paperweight.

In short, bowling balls are finely-tuned technological structures these days which last as long as the technology is in good enough condition. If the cover stock or core of a bowling ball is severely compromised, you’re likely going to have to buy a new bowling ball.

Closing Thoughts 

So, what are bowling balls made of? The answer isn’t exactly simple. Bowling balls have evolved from simple wood and rubber spheres with limited technological import into machines which have been repeatedly tweaked – chemically and structurally – to maximize efficiency and effectiveness.

A modern bowling ball is much, much more than meets the eye! But, it’s also what meets the eye which needs to be examined in order to appreciate just how much work it takes to make a modern bowling ball go and go right!

If you’re curious on what type of bowling ball is right for you, you can check out our best bowling ball guide over here.