[KenWittlief]

what kind of drive train are you using? how low is your transmission geared down?

ifyou are using either of the FIRST transmissions and you have the drill motors in low gear, and you have a two wheel drive set up (with skid plates or castors) then you will not need to put heatsinks on the drill motors.

they have blowers built into them, and as long as you dont block the openings next to the brushes, they will cool themselves.

the problem with heatsinks is, if your motors are getting so hot that you think you need them, you are destroying your motors and the heatsinks wont really help anyway. The reason is the current in the motor flows through the windings, which are on the armature in the center of the motor - the part that spins. The outside of the motor is only the magnets - so if the armature is getting so hot that the magnets are cooking, imagine how hot the windings are.

and when you put a heatsink on, what are you makeing contact with???? the metal case around the magnets - not the armature - so all you are doing is cooling the magnets down, and not providing any additional cooling to the windings - the part that WILL fail when it gets too hot (the insulation will bake off the wires, or the silver solder holding the wires to the commutator will melt.

Robots usually dont cook their drive motors unless they are geared up too high, or they are using tank treads, or 4WD with front wheels that dont slide sideways very easily. And even then, if you have your bot geared down enough (say 3 feet per second) then the motors will still be able to spin fast and keep themselves cool - on the windings, where it counts.