ASE Automobile Parts Specialist (P2) Practice Test 2026 - Free ASE P2 Practice Questions and Study Guide

The primary distinction between disk brakes and drum brakes lies in their design and operation. Disk brakes employ a rotor, which is a flat circular component that rotates with the wheel, and a caliper that contains the brake pads. When the brake is applied, hydraulic pressure pushes the pads against the rotor, creating friction that slows down the wheel.

In contrast, drum brakes consist of a drum that rotates with the wheel and brake shoes that press outward against the inner surface of the drum when the brakes are engaged. This design relies on the friction created between the shoes and the drum to stop the vehicle.

This fundamental difference in components and operation affects their performance characteristics. Disk brakes generally offer better heat dissipation, which leads to more consistent braking performance, particularly under heavy or repeated use. Understanding this distinction helps in making informed decisions about vehicle design and maintenance.