The Pro 4 Rear hubs use a new 44 tooth ratchet mechanism. The flange diameter is increased, adding important stiffness to wheel builds. The 17mm axle runs on five cartridge bearings. Pro 4 hubs are 6 bolt disc compatible and available with 28,32 or 36 holes. Choose from six anodized colours. Rear hubs with Shimano compatible freehubs features a larger bearing, will be supplied ready to take 11sp cassettes. Available sizes rear: 170mm, 177mm, 190mm, and 197mm. Available sizes front: 135mm, 142mm, and 150mm.