Am contemplating building a ebike from a cheapish mountain bike I have and getting a squad or one of those ebikes for kids that are made for off road use. Was wondering has anyone ever considered or done it. My plan was shifter style using sbp freewheel crankset and motor mounted so drive is all from one side. Has anyone any idea how hard it would be to extend wiring for say throttle? Is there a premade extension I could get or is it case of cut and solder?