The Shimano Dura-Ace high-flange rear track hub is a single-sided threaded track hub for fixed gear track cog only. The higher flange increases wheel stiffness and also provides eye-catching good looks. A heavy-duty steel axle with high quality bearings make the Dura-Ace high flange track hub durable and reliable. This hub an ideal choice for a track or fixed gear bike. 120mm spacing fits track and true fixed gear framesets only.