Alright I've been to a LOT of local bike shops today, two places sold out today of 20-22t and the others just looked at me dumb founded at that size... I think I'm just going to order both a 20 and a 22 just to get started from amazon... on the other hand before I do that I'm going to head out to the dump tomorrow and see about a bmx donor bike, since I need drop outs a BB and a headtube for a different project as well... just about any bmx flywheel with the right teeth will do as far as I know as long as it's not cassette.. or there's also this... http://www.amazon.com/Dimension-Coas.../dp/B004JKIEFU I'm asking about it in the SS/FG forum as well, but can you guys tell me if this would be worth my time?