What causes friction inside a brake drum?

Friction inside a brake drum is primarily generated when the brake shoes and linings press against the inner surface of the drum. When the driver applies the brakes, the hydraulic pressure from the brake fluid forces the brake shoes outward against the drum. This contact creates friction, which is essential for slowing down or stopping the vehicle. The more surface area that comes into contact, the greater the friction and the more effective the braking action is.

This mechanism is fundamental to how drum brakes operate, as it converts kinetic energy into heat through friction, allowing the vehicle to decelerate. Understanding this principle is crucial for driving safely and effectively, as it impacts how responsive the braking system will be under different conditions.