Alfine disc & rim brake dynamo wheel system brings high performance technology to a affordable price point The hub uses angular contact bearings designed to cradle the balls giving both radial & lateral support for superior strength & durability in real world riding conditions. They also offer precision bearing adjustment & easy maintenance High performance 6 volt 3 watt hub dynamo Easy to use Centre-Lock disc rotor mount for secure hassle free setup Machined braking surface for use with rim brakes & butted 2.3 / 1.8 / 2.3 spokes Double contact seals 700C rim compatible with 28-47C tyres 100 mm O.L.D.1300 grams