So far, I got up to 39mph on my Baja MB200 (Stock 6.5 Predator, with scrap built header, a TAV2, with 10t front and 50t rear sprocket. That was with the driven spring in the 2nd hole and I ran out of space to ride before I ever wound out the motor. I ended up changing the spring to the 3rd hole for more torque, since I wanted to climb not fly.:laugh: