Shimano dura ace 9000 road rear hub elite road racers demand the best. Dura ace components are precision engineered for ultimate performance and durability. The dura ace 9000 road rear hub features an oversized alloy axle for increased rigidity and an improved freehub design for faster engagement and instant power transfer.features improved freehub body design for quick pawl engagement for instant power transfer oversized axle has increased rigidity both torsionally and laterally, removing axle flex when under compression from the quick release, thus improving rotational smoothness and durability labyrinth double contact sealing low friction seals effectively shut out water, mud and dirt without affecting rotational smoothness borozon treated bearing races super mirror finish bearing races reduce friction providing silky smooth and precise bearing rotation cold forged and machined aluminium hub shell and oversized 7075 alloy axle combined with a titanium freehub body all keep the weight to a minimum quick and easy bearing assembly and maintenance via a simple to use digital click adjuster, removing the need for cone spanners 8, 9, 10 and 11 speed compatible titanium freehub body weight 247 gramsa 2 year warranty is offered with all shimano products from chain reaction cycles 3 years on dura ace and xtr products.buy shimano wheels tyres from chain reaction cycles, the world's largest online bike store.