Car came with a 13/56 gearing. It also came with an optional 19 pinion.im running a 4000mah 2s. I put an 18 tooth pinion on and love it, however it gets hot. Esc was 170 the motor was 240! I bought some other smaller pinions to try as well but really like the performance with the 18. I picked up a motor fan that I haven't installed yet. And from what I understand you cannot go to a bigger spur? Any suggestions?