my slash 4x4 has a 54t spur gear on it and i am running a 13.5t burshless motor
What is the kv of your motor? Turns are more for a brushed motor. What motor do you have?
Slash Ultimate El Sob special MIP King Headz 3PL
i have a novak 13.5t ss motor
At 195 watts
540 can, With 3mm shaft.
I would start low, say 10T pinion.
What ESC are you running?
Slash 4x4 MT
i am running a lrp sxx race spec esc