I going to make my own Fixie!! I do have a question that I need help with. I have a pair of Mavic 501 (7 speed freewheel) hubs that I'd like to convert to fixed. Can I change the spacing from 126 to 120 to fit in a track rear triangle? Can I put a fixed cog or a single speed freewheel on it? Did I forget anything else of importance.
You could do all those things, but it would not be worth it with an unbuilt rear hub when you can get a proper track or flip-flop hub w/ a reverse threaded lockring and solid axle w/ nuts fairly cheaply (about $35 and up) from many sources.....Surly, Van Dessel, Harris Cyclery, etc. It is easier to build the wheel and get the chainline right w/ this kind of hub, and you also end up w/ a stronger wheel w/ little or no dish