Well from this thread, the rear brake is up in the air, and the crank is not a problem. This guy is relentless though, and uncooperative. now he has posted a comment saying my dropouts are too thin for a fixed gear (they are the normal thickness of any 70's road bike). He further states the crank should be a single piece of metal with 5 spider arms. It cant really be that important what kind of crank you use can it?