Originally Posted by
Rhodabike
It looks like these bikes have the same kind of rear drop-outs as track bikes have, with the slot facing backwards. One of the road "fixies" that some companies are now selling might be suitable for conversion.
As tatfiend alluded to, the problem with belts and standard bike frames is how to get the belts on and off. With a chain you use a chain breaker or master link. There's no such animal with a belt so the frame has to be specifically designed to allow belt installation and removal.