Just changed the orig 38 tooth rear sprocket of my fat tire Trailamster MB200 to a 60 tooth, Using the torque converter I recently purchased, this thing will climb any hill from dead standstill. Throwing dirt and gravel. It still hits approx 35 mph on top end .Would not change a thing top or bottom end. Just a old man still having fun like I did 50 yrs. ago.