Bicycle wheel metal or carbon fiber rim which holds a pneumatic rubber tire. A hub is the center part of a bicycle wheel. It consists of an axle, bearings and a hub shell. The hub shell typically has two machined metal flanges to which spokes can be attached. Hub shells can be one-piece with press-in cartridge or free bearings or, in the case of older designs, the flanges may be affixed to a separate hub shell. The axle is attached to dropouts on the fork or the frame. The axle can attach using a: Modern bicycles have adopted standard axle spacing: the
Wheel hub motor axles, provides a significant weight and manufacturing cost saving, while also decreasing the environmental impact of the product. The major disadvantage of a wheel hub motor is that the weight of the electric motor increases the unsprung weight, which adversely affects handling and ride. The wheels are more sluggish in responding to road conditions, especially fast motions over bumps, and transmit the bumps to the chassis instead of absorbing them. Most conventional electric motors include ferrous material composed of laminated electrical steel. This ferrous material contributes most of the weight of electric motors. To minimize this weight, several recent wheel-motor