Gearing for Speed
Spur gears (the larger of the two) are typically plastic and connect directly
to your transmission, pinion gears are metal and connect to your motor, usually
with a set screw.
Spur and pinion gears are sold by "pitch" and "teeth". A 48 pitch spur gear will
not work with a 64 pitch pinion and vice versa, they must match. Teeth are just
that, the number of teeth the gear has.
Since the pinion is much easier to change, and many more tooth sizes are available,
I consider the spur gear to be more of a permanent change.
I'm looking for a balance of low end torque and top end speed. This 81 tooth
spur gear from Kimbrough and 18 tooth pinion from Bolink should be a good starting
point to make adjustments.
Price: about $4.00 each.
A typical spur/pinion gear setup on an RC-10T
When changing your pinion or spur gear its a good idea to check your owner's
manual and use the stock set up for an adjusting starting point. Also some motors
will recommend a set up. Once you've decided on a spur gear, try different
pinions and drive the same area, if you
plan on racing, have a buddy time your laps. When you do change pinions, make your
change only by one tooth either way. Over gearing, or using a pinion with too
many teeth, is a good way to burn up your motor, especially in off road conditions.
A good rule of thumb is that if your motor gets too hot to touch for 5 seconds after
a run, you need a different pinion, one with less teeth.
A decent free program for figuring out your gear ratios, and other helpful tips is Easy R/C 6.
Check it out!
Using the proper spur gear and pinion can greatly, and inexpensively, improve
your kit's performance. You should consider changing your gears when you
get a new motor, change your track surface conditions, change your tire size, or simply want to
see what more speed you can get out of your kit.
The lower you get in number of teeth on your pinion, the less top end speed you
have. The trade off is that you get more low end torque, and quicker acceleration
off the line.
