Brakes currently have disc brakes and drum brakes as well as air brakes. Many older cars are front and rear drums. Many cars are now disc brakes. Because the disc brakes have better heat dissipation than the drum brakes, in the high-speed braking state, it is not easy to cause thermal decay, so the high-speed braking effect is good. However, in the case of a low speed cold brake, the braking effect is not as good as the drum brake. The price is more expensive than the drum brake. Therefore, many medium and high-class cars now use full-disc brakes, while ordinary cars use front and rear drums, while relatively low-speed, trucks and buses that require large braking force still use drum brakes.
The drum brake is sealed and shaped like a drum. There are also many brake pots in China. It is rotating when driving. Two curved or semi-circular brake shoes are fixed inside the drum brake. When the brakes are applied, the two brake shoes are externally stretched under the action of the brake wheel cylinder, and the brake shoes are supported to rub against the inner wall of the brake drum to slow down or stop.