- Jul 2, 2018
I don't know why they sell those with a 3:1 box, they're useless on an adult-size bike. You'd need a 16- or 20-inch wheel to make that work. You'd end up with one hell of a goofy bike. Better to swap the gearbox. If you want one that won't blow up, get a Grubee belt drive. You'll end up with a bike that accelerates from a stop, will climb hills and tops out around 30-35 mph.