It has to do (I think--I'm not a mechanic) with how wide your bottom bracket is (?), and whether or not that will allow the front chainring to line up straight with the cog on the hub in back. The wheel I'm offering has a formula hub that came stock on the '08 fuji track. Maybe someone on here can help you with what you need to measure. That's about as much as I know about any of it. Good luck, and let me know if you need the wheel.