I'm running a 4500kv motor from SMC and the 54t spur with 13t pinion and on our longest straight (about 75ft.) and this thing wasn't even close to topping out and the motor was getting around 165 to 175 degrees and i can't go down in pinion size because not enough adjustment to go any smaller on pinion, so now i'm back to the 62t spur and 14t pinion and may go down to a 13t pinion. but yes this thing is really so far a good truck haven't broke anything yet.