Surly Ultra New Fixed/Freewheel Rear Hub Description: The Surly Ultra New Fixed/Freewheel Rear Hub is constructed from 6061 aluminum alloy with mid-height flanges. The Ultra New Hub uses hollow axles paired with threaded fixing bolts, making the conversion to Quick Release quick and easy. It also uses non-adjustable 6901 model bearings so you can throw your wheel on, tighten the bolts, and start riding. Note: Quick release skewer is not included Features: Axle is quick release and bolt-on compatible Stainless 6mm bolts are included 6061-T6 forged hub shell 4130 Cromoly axle and stainless cones Axle/cone system uses a specific shouldered axle that allows the hubs to be completely adjustment-free and simple to service 6901 bearings Aaggressive knurling on cones and bolt caps for reduced slippage Specifications: Position: Rear Brake Type: Rim Brake Axle Type: Bolt-On or Quick Release Hub Spacing: 10 x 120mm Spoke Count: 32H Spoke Type: J-Bend Left Side Flange Diameter: 54mm Right Side Flange Diameter: 54mm Left Side Center to Flange: 31mm Right Side Center to Flange: 30mm Bearing Type: Sealed Cartridge Color: Black Weight: 312g