How small of a pinion can I run with this setup?
 

Right now I'm running a Tekno Conversion on my MBX5T and the smallest pinion I can use is a 14T. I want to run a much smaller pinion so that I can volt up for efficiency.

Does anyone know how small of a pinion I can run with the RCM motor mount for the MBX5T? I'd love to get down to a 9T but not sure that's possible? I'd even settle for a 10T.

Depends the width of your motor, with my RCM motor mount and my NEU-Castle 1520/1Y I can gear down to 12, maybe 11 but I am not sure. Under that, the motor hit the rear chassis reinforcement.

Thanks, I'm running the Castle 2200kv motor.

The width is the same as my 1600Kv Castle motor ! So 12 maybe 11T !

Can any light modding be done to get to 9T or 10t? I borrowed an RCM mount from a friend. Going to see what I can figure out. I'd like to get to 9T if I can since I have one already.

You can maybe cut a little the chassis reinforcement to fit the motor with the 9T... Keep us posted ;)

Maybe shave the fins down a little too on one side of the motor, shouldnt be too much of an issue since the air version of the CastleNeu motors have squared off fins on either side of the motor: clicky