A wide crank set is used with a 79cc or 212cc motorized bicycle so the pedals will clear the engine. This versatile kit utilizes a 12" keyed shaft which rides on precision bearings. The bearing hangers in this kit should be welded to the bottom bracket however bolt-on is possible. Lock collars prevent side to side movement of the axle. The short 5-1/2" cranks get keyed to the shaft and secured with a bolt and washer at the end of the threaded shaft. The cranks accept 9/16 pedals. The optional 5/8" mini hub can be secured to the keyed shaft at any location which provides a huge convenience for lining up the drive sprocket with the driven sprocket on your rear wheel. We have also converted some of our bikes to #35 chain for the pedal side and we can use a small #35 engine sprocket (p/n 16440) it tight clearance situations.