Sometimes you search on the internet and simply do not find the info you need to solve your problem. Bummer. You then need to think about it yourself and figure out a solution. I think this is what people did before Google and the encyclopedic internet came along. I wanted to learn to ride a bicycle backwards and possibly fab up a giraffe uni, but did not have the money. Central to both endeavours is the fixed rear hub, one that when you pedal backwards it goes backwards, and when you pedal forwards it goes forwards. This is how I converted a 20″ bmx bicycle freewheel hub into a fixie hub.