Instead of a Pinion, Use a clutch bell? and double check my gearing please.

[_paralyzed_]

1.- Tekno RC makes a clutch adapter to use standard clutches on electric motors. This would give you an area for stress relief, but also adds maintainence to your vehicle because of worn out clutch shoes and bearings. Another factor to consider is that the clutch systemadds the width of the clutchbell to the overall length of your motor/gear combo.

It is a viable option, but not one I would choose.

2.- That gearing is correct. A transmission offers the gear reduction you need for a good spur/pinion combo, but adds a weakpoint. A CD eliminates the weak point, but doesn't have the gear reduction necessary for an ideal spur/pinion combo. But it will work!!