I would love to build a motorized version of this (pictured bike). However the drawback is, as I see it the acceleration and breaking are limited by the total weight of the rider + weight of the drive system. If you exceed that weight you will be rotating with the outer wheel. So steep hills(without creeping) & fast stops would be impossable. Would be cool for shows & parades but other than that pretty much useless. Any contrary input, as I would like to build one!