Pros and cons of drum brakes
Self-brake action: The drum brake has a good self-braking function. Because the brakes make the sheet open, the wheel rotates with the outer brake drum to twist an angle.
(Of course, it won't be so big that you can easily see that the brakes make the extra-plate tension (brake braking force) larger, the more obvious the situation is. Therefore, the large vehicles still use drum brakes, except for lower costs. The drum brakes of large cars and small cars may differ only in large-scale pneumatic assistance, while small cars use vacuum assistance to help brakes.
Lower cost: The drum brake manufacturing technology is lower in level and is also the first to be used in the brake system, so the manufacturing cost is lower than the disc brake.
Due to the drum brakes, the sheets are sealed in the brake drums, causing the brakes to dissipate the pieces after the sheets are worn, affecting the contact surfaces of the brake drums and the sheets and affecting the braking performance.