Great discussion here and thanks for everyone's input.
KnightKrawler used 2 AndyMark Nano Tube 20's with hex shafts in the stock 12.75:1 ratio. One CIM per wheel and each wheel driven directly from the gearbox. Since we need a drive motor per wheel, we used this as an opportunity to leave out chain. As noted before, the wheels are AndyMark 8" HD mecanums that come with side rollers which we do think help to smooth out the movement of "Silverfish" as it transitions between mecanum rollers. The robot weights in just under the 120 lbs. limit with the 84" blocker and GoPro installed. I bet "Silverfish" was just over 118 lbs. for its fighting weight.
While we did develop field oriented drive code this year, it was not utilized. The robot is driven in open-loop as we do not use any sensors on the drivetrain. We did have a gyro on board and tinkered with auto robot orientation for loading and hanging, but it was never used in the competition code.
Here is a picture of the drivetrain:
I hope this clears up some of the questions, let us know if you have any more.
Thanks,
Nate
2052 KnightKrawler Mentor