Generally, trucks are brake drums

Update:16-08-2018
Summary:

Generally, trucks are brake drums. The rear brakes for […]

Generally, trucks are brake drums. The rear brakes for small cars are generally drum brakes. The discs and drums have obvious differences in appearance. The disc brakes can be seen outside, drums. The style is built in.

In the brake drum, hydraulic pressure is applied to the piston, which pushes the curved brake shoe. The friction material of the bond or rivet on the brake shoe presses the inside of the brake drum, slowing the rotation of the brake drum and the axle, Brake drum and then these old cars will stop - if successful! Brake discs have been used in aircraft and industrial applications. The friction material (brake pad) grips the rotating brake pad by the hydraulic pressure applied to the brake caliper. Brake discs don't seem to be as "scratched" as brake drums, so they provide better directional stability when parked. Unlike the enclosed brake drum, the brake disc is open, which has both advantages and disadvantages.

Trucks are drum brakes, and minivans are usually front discs and rear drum chambers. For small passenger cars, the cheap ones are usually the front and rear drums, and the high-end ones are disc brakes.
Disc brake, good braking force and good heat dissipation. But the disadvantage is that the cost is higher than the drum style! However, it is necessary to increase the braking force like a heavy-duty truck. Domestic manufacturers can't produce the disc brakes. Only the imported ones are expensive, but the price is very high. Drum brakes are much cheaper.
In short, disc brakes are the direction of future development, and small cars are basically popular. The popularity of big cars is cited as high prices! With the advancement of technology, disc brakes will become mainstream.