Vehicle keel, also called rim, wheel and tire bell, is a metal part that supports the tire internally, and the center is the vehicle hub installed on the axle. There are not so many requirements for appearance, but the heat dissipation must meet the requirements, and the process uses paint, which takes a long time. Steel wheel hub: The biggest advantages of steel wheel hub are simple manufacturing process, low cost and strong metal fatigue resistance. The disadvantages are obvious, ugly appearance, heavy weight, large inertial resistance, large heat dissipation and easy to rust. Alloy wheel hub: Alloy wheel hub is quite light in weight, with smaller inertia resistance and higher manufacturing accuracy than last year. When driving at high speed, the deformation of alloy hub is small, which is beneficial to improve the straight-line driving ability and shorten the fuel consumption time. The heat dissipation of alloy wheels is about three times that of steel wheels, which plays a necessary role in improving the braking performance of vehicles.