21 pinion on a evader tranny what tires are you running?, either way you are over gearing you are over heating the ESC and my suggestion is lower the pinion and get your self a temp gage.. there cheap 20 bucks gets you a decent duratrax temp gage. it should not be over 175. you can do the finger test too, if you can keep your finger on the ESC or motor for more than 5 seconds then the motors and ESC are running good and cool, if not your thermaling it.