In RC racing (and generally,) gear pitch simply refers to the size of the teeth on a gear.
The most common gear pitches today are 32, 48, and 64, but some gears are classified by "MOD" instead of pitch. You will often see 0.8 MOD gears (which are very close to 32 pitch), but there are others as well such as 1.0 or 1.25 MOD. These gears have larger teeth and are usually found on large scale or heavy-duty vehicles.
You will most often need to deal with gear pitch when it comes to matching up your pinion and spur gear. Whenever you are meshing a pinion and spur or any two gears, make sure the teeth of both gears are the same pitch. If they are not, the gears will be loud and may not work at all, and even if they do "work", they will wear and fail much more quickly than expected.
When calculating gear ratios, you can safely ignore the pitch because all meshing teeth will be of the same pitch.
Smaller gear teeth
- Quieter
- More fine-grained gear ratio adjustments possible
- More efficient
- More easily damaged
- Ideal for on-road and small-scale cars
Larger gear teeth
- Louder
- More durable, especially for high-torque applications
- Ideal for off-road and large-scale cars