I put the smallest pinion I could fit on the there but they strip out very easily due to motor plate flex. I have a couple brass pinions but my 20mm Castle motor and 3s lipos should be here soon. I already have a NIB Quark 22A ready to go for this little rig.
Oh and it still likes to shut down after minimal run time. I think it's due to the load on the motor. I might get a Micro-T just to put in the Xcelorin system and have 1/36 fun.