We use a good set of downhill mountain bike wheels. This allows us to use a disc in the front. We bolt our sprocket where the disc would go on the back. The rims are strong and give us no problems even on our gx200 bike that goes over 50mph.Well I will be running a gx200 clone.. So I need the stopping power. Also the fork I'm running is disc only. So disc up front, and then I need a rear disc hub to mount a sprocket on... Or get manic mechanic sprocket hub adapter on a coaster hub. I'm aiming for 50-60 mph tops so it needs to be built well!