Gear ratio maybe seem scary at first, but really it is quite easy, when one understands it well. In the world of RC racing it simply points to the size of the teeth on your rc gear, nothing more complex than that. The number of the pitch shows how many teeth fit one inch of the diameter of the rc gear.

So, for example, if you stretch a 48-pitch rc gear in flat form, you find 48 teeth for one inch. That measure of one inch, that it relates to, one calls the pitch diameter, and it forms the basis of the whole system.

RC Gear Pitch: What It Means and Why You Must Match Gears

Various RC-type gear setups require different pitches, and the choices are wide ranging. In the hobby community you commonly will meet 64P, 48P, 32P or 25.4P. During building of 1:10-scale race cars, 48P shows everywhere, it is the usual standard for off-road racing.

When you drive 1:8-scale vehicles, those chiefly use mod-1 gears instead. Notably, some Traxxas RC brushless cars come from the factroy with already installed 32-pitch spur and pinion gears.

Here is where many folks commonly mess up. A high number of pitch actually points to smaller teeth, not bigger. Imagine that: gears of 64 pitch have much more tiny teeth than those of 48 pitch.

Hence they run more smoothly and do not overload your drivetrain until something breaks. Also, pitch and rc gear ratio is two different things. Pitch concerns only the size of teeth, while ratio deals with speed and torque…

Do knot mix them up.

Your spur and pinion gears must have the same pitch. If you mix them, everything fails. Here is the interesting part: a 48-pitch 20-tooth pinion, meshed with an 80-tooth spur, works the same as a 32-pitch setup with a 15-tooth pinion and 60-tooth spur, if the rc gear ratio matches.

The pitch itself does not affect the speed, heat or stress on your electronics, that all depends on the rc gear ratio.

Metric and imperial pitch systems seem almost the same, but they do not always match well. A 0.5-mod gear and a 48-pitch gear is quite close in size, even so they are not swappable. Tamiya uses mod-0.6 gears, that seems very close to 48 pitch, but they are not the same.

On those cars, switching to a high-speed gear set opens ways for replacing with 48-pitch gears instead. Similarly, 32 pitch and mod 1 have totally different sizes, if you put a mod-1 pinion over there, where a 32 pitch belongs, you risk broken teeth or stripped gears.

To find the unknown pitch of a rc gear does not need rocket science. Calipers work well, although basic rulers also help. Websites with calculators simplify the task, simply enter the outer diameter of the rc gear in millimeters and the tooth count shows.

Even better, check the rc gear itself for printed marks, when you pull it from the housing. Using wrong pitch for a pinion and trying to mesh it with a mismatched spur is amistake that causes bad problems later.