To build this system, I started with a BMX double-sided hub. On the drive side, I first added a freewheel from an electric scooter(off ebay).These freewheels have a flange for a bolt-on sprocket. Next, I took a large sprocket from a 10-speed cluster and drilled holes for the bolts and fitted it to the scooter freewheel. When these freewheels are screwed onto the hub they have some thread left, to which I screwed in a bottom bracket cup from an English-type bike. This gives more thread to screw the second freewheel to. . Next, I modified a Schwinn cruiser frame to accept the wider hub by first cutting the bridge. Next, I placed a bolt in the rear drop outs and used a car jack to spread the stays.(gotta love those heavy steel frames.) Then I installed the hub and checked the chain clearance. When all was right, I brazed in a new bridge. |