box 12 gears

[slicknick]

hey monty,

Ive been having trouble with my box 12 with stripping gears off my car. With plastic gears I start out with a perfect mesh and by the end of a race the teeth on the spur are bending and braking.
and on metal gears it the same problem just backwords its bending the teeth on the pinon.Could this be a product of chasis flex? too much tourqe?
thanks

[Monty @ B.O.W.]

Nick,

Its something in your setup, and as you suspect it has to be something moving that shouldn't. Plastic gears are normally reliable (barring crash damage) even with the extreme power of Group 7 motors.

First, make sure the starting mesh is good. It should not only feel smooth, but have only a small detectable backlash. Many racers routinely use paper shims when setting the mesh to get a reasonable backlash of approx. .003".

Next, make sure the setup is as rigid as possible. This means having the motor soldered in two places, the bushings soldered into the chassis, and both the motor and chassis sideplay limited by suitable washers. A good goal is enough play to feel, but not enough to see! Make sure that all the solder joints in the back of the chassis are solid.

Finally, make sure you are using quality parts. The pinion gears should be the hardened steel solder on type. I'm worried about that when you describe pinion wear while using metal spur gears. Again, this doesn't normally happen if everything else is OK.