1) The stock screws that hold the idler wheel halves together are totally lame. They only bite about 1 thread and they are hard to insert. I very easily stripped that one thread. The stock screws are 3mm x 6mm long - I replaced them with 3mm x 8mm hex socket stainless steel screws. They are much easier to install and they bite nearly the full length of the thread inside the idler wheel. The only potential problem is that the caps on the screws are higher and if all the planets are in alignment it is possible for the cap to barely touch the road wheel rubber. I don't think I'm going to worry about it, but if it does become a problem I think another washer on the idler axle would fix it.

2) Refining my goals - I tried to justify my use of brushless motors in my other post http://www.rcuniverse.com/forum/m_10967806/tm.htm. When I was thinking about powering the metal mato I had images in my head like the pictures below - tanks pulling out of ditches or climbing over high berms at high angles. One of those tanks is from WWI actually. Basically I wanted a tank that could not get stuck because of lack of motor power. Getting stuck because of traction is a separate issue that we really can't change (except maybe with weight.) As I said in the other thread, the main problem we have is lack of mutispeed transmissions. I've been trying to make up for that with increased torque. But this is like trying extreme hill climing in 8th gear (of the real Tiger), which the original could never have done. So maybe my goal is unreasonable, I don't know yet. I'm still in the early stages of the experiment - have more things to try.

I don't think we need 8 speed transmissions. Even two speed might be just fine if the ratios were wide enough apart. Image if we had the same 70:1 ratio as the Mato 3:1 for second gear, but first gear was something like 350:1

Russ