[artdutra04]

The first stage reduction (between the CIM motor and shifter cluster shaft) looks like it's geared faster. Don't do this in a gearbox if your intention is for the output to be slower. Gearing faster in one stage only to gear slower later is just wasted weight, space, and lowered efficiency. Instead, do like AndyMark does with a 12t pinion on the CIM motor and a 40t gear on the shifter cluster shaft.

As for the higher DP gears on the shifter output, if you could fabricate a gearbox to accurate enough tolerances to properly mesh the 20DP AndyMark shifter gears, you can easily use 25p roller chain or timing belt instead of the higher DP gears.