[BP-Revo]

Yes, overgearing is gearing so high that the motor has to work excessively hard. Undergearing is geairing so low that the motor is always running at an excessively high RPM. Both will generate heat. This require you to find a sweet spot in the motor.

Basically, its best to have a few gears to try out. If the tallest gear ran really hot, and the lowest gear ran rather hot, but the middle gear ran ok, then you know that the middle gear is a good place to start, and you can adjust from there.

As for the 35/60, thats gearing WAY too high. 96/12 sounds very low.

Gear up means lower the ratio or increase pinion size/decrease spur size. Gear odwn means increase ratio or decrease pinion/increase spur size.

In the desert, the sand creates more resistance, so you should gear down 10-15% at least.

On the track, you should probably gear it so it just tops out on the straight (unless your track is excessively small or large, where it causes the motor to run hot if you gear like that, just gear within the confines of the motor).

On the street, gearing is preference. You can gear lower at a hopes you can pull a wheelie or do some nice burnouts, or gear high to do some touring car-like speed runs.