[RC-Monster Mike]

Originally Posted by Ryu James

the provided pinion gear will be 8mm bore for a 8mm shaft but i think you can get a bore reducer on the RCM store that can reduce the pinion bore from 8mm to 5mm. so you could go with either shaft size although i would recommend using the 8mm just from experience with my own 1/5 conversion and the amount of torque on the Neu 22xx motors. in my opinion, the slightest mistake in gear mesh or chassis flex would easily snap a 5mm shaft on these large, heavy conversions.

Exactly. :)