Cam-Do: How Your Bass Drum Pedal Transfers Energy Into Sound


Bass drum pedal preferences seem to inspire some of the most ferocious loyalty among drummers of all stages and ages. Arguments over what’s “best” have pervaded the community for decades, seamlessly migrating from drum shops to online forums and social media.

Thankfully, though, there is no actual “best.” Pedal preference is determined entirely by the user’s style, technique, and anatomy (and, I guess, receptiveness to marketing). Those factors can lead to significant differences in opinion, and can even change over time.

For example, I’ve really enjoyed pedals with concentric cams over the past few years, but a recent ankle injury affected my foot’s range of motion (no joke, I slipped and fell chasing my garbage can down the street in a rain storm), and now has me leaning toward offset cams because I just can’t generate the same power I previously could from the heel-down position. That whole incident forced me to take a hard look at my technique, as well as dissect every single feature on my pedal to see if I could get it to do some of the work I was doing before I got hurt.

Now, let’s get into how cam types affect pedal response.

There are likely a few different cams on your pedal, but we’re only going to focus on two types. First, there’s the driver cam, which is the large, center-mounted sprocket that is connected to the footboard with a chain or strap. The shape of that cam dictates the way energy is translated from your foot into the motion of the beater. Second, there are rocker cams, which maintain and transfer tension from the pedal spring to the main axle.

While there are some differences in size and exact shape within each style, there are really only three main driver cam types: concentric, eccentric, and adjustable.

Tama’s Rolling Glide is an example of a concentric driver cam

Concentric or round cams have semi-circular frames that translate energy smoothly from the beginning of each stroke straight through to when the beater strikes the bass drum head. Round cams are sometimes preferred by players in need of greater dynamic range because they give the user complete control of the stroke velocity at every point. They’ve also found favor among drummers playing ultra-fast tempos for long periods of time as they can be set up to produce the most efficient transfer of energy (less effort per stroke) of any traditional cam type.

Tama’s Power Glide is an example of an eccentric driver cam

Eccentric or offset cams use irregularly shaped sprockets to just slightly delay the energy transfer from boot to beater. The resulting feel is a hair slower at the beginning of the stroke, but accelerated at the end to add power. It’s a subtle shift in feel under foot, but it can add a noticeable amount of punch, especially behind low- to mid-volume strokes. Offset cams sort of became the norm among rock and pop players over the past couple of decades, due in large part to their consistently powerful followthrough, and because the difference in feel is less perceptible when playing heel-up.

Yamaha’s Quick Adjusting Cam/Link is an example of an adjustable or modular driver cam

Finally, Adjustable or modular cams are pretty self-explanatory. They allow the player to easily switch between concentric and eccentric cam types without fully dismantling the pedal. Some can even accommodate settings between fully eccentric or fully concentric to give the player full control over their preferred pedal feel.

In line with adjustable cams, there are several pedals available with easily swappable cam brackets that can be switched in and out without dismantling the pedal. Many of these units take the eccentric design to the extreme, using sharp angles to add additional power or control.

Tama’s Speedo-Ring rocker cam

Rocker cams don’t get quite as much shine as driver cams, but they play an equally important role in your pedal’s movement and action. Rocker cams connect the pedal’s tension spring to the main axle, allowing the axle to rotate while maintaining tension so the pedal returns to its default position after each stroke.

Rocker cams range in build style from simple bushings to high-performance ball bearings to further reduce friction. If you’re encountering unwanted resistance from your pedal, and adjusting spring tension doesn’t seem to make any difference, try taking a look at that rocker cam to make sure it’s correctly mounted and clean. Sometimes loose components or debris can inhibit motion at that point, so it’s a good idea to give it regular check-ups. If you’re still unsatisfied with your pedal’s action, there are a few aftermarket rocker cam replacements that allow you to add an eccentric-style motion to that joint for more power or punch.

If you’re unsatisfied with your pedal’s play, put some time into diagnosing exactly what’s troubling you and see if making any adjustments might help. If not, you’ll at least have a head start on knowing exactly what you need out of your next pedal.