Hign-concerned Chemical : None is_customized : Yes Material : Bearing Steel Model Number : MH-P08F 30.6x41.8x8 mm Brand Name : FUSHI Origin : Mainland China Certification : None Hubs Bearing Guide The hub is the central part of your bike's wheels (front and rear), which connects to the wheel's rim via the spokes and through which the axle is fitted, enabling the wheel to freely spin on two sets of bearings. As bikes have front and rear wheels, so too have they front- and rear-specific hubs. The front hub is simply designed to enable the wheel to spin, while the rear hub is a little more complex as it also forms part of the bike's transmission the cassette or sprocket which drives the rear wheel is attached to the rear hub, which on most bikes also features mechanism to allow you to coast or freewheel (exceptions being fixed-gear or 'fixie' bikes and track bikes). Your wheels spin more than any other part of your bike. Therefore, having the best bearings in this application is crucial to producing the best results. DETAILS Item: TH870 Closures: 2RSSealed Structure: Ball Bearing Dimensions: 30.6 x 41.8 x 8mm ID (inner diameter): 30.6 mm OD (outer diameter): 41.8 mm Width: 8 mm Quantity: 1 Lot =1 PC A Special Structure Besides the patch where your tires meet the road, what's the next spinning component that can either slow you down or let you roll faster? You would be correct if you said hubs, but that compo