The Shimano Dura-Ace high-flange rear track hub is a double-sided track hub threaded on both sides for fixed gear track cogs 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. The double sided aspect of the hub allows different cogs to be used depending on riding conditions simply by just flipping the wheel. 120mm spacing fits track and true fixed gear framesets only.