Brake rotors vs. Brake drums

September 10, 2020

Most new vehicles come equipped with brake rotors, commonly known as disc brakes. Typically, both the front and rear are disc brakes, however, rear drum brakes can be found in some smaller cars or older vehicles.

What is the difference?

Disc brakes use a disc-shaped, metal rotor that spins inside of the wheel. When pressure is applied to the brake pedal, a caliper, fitted with brake pads, squeezes against the rotor. The caliper is the bridge between the hydraulic system and the wheel brakes, which provides the force when the pads are clamped against the rotor. The car will slow down as more pressure is applied to the brake pedal.

Brake rotors are considered better than drum brakes because they allow a significant amount of heat to dissipate, and they provide better braking performance, particularly in wet conditions. Their design allows air to circulate around the rotor, which carries away the tremendous heat generated from the friction that comes from braking. 

A drum brake consists of a metal, drum-shaped housing, typically made of iron, that covers a set of curved brake shoes. The drum brake is bolted to the wheel hub and rotates with the wheel. When the brake pedal is applied, pistons push the shoes outward against the drum to slow down the wheel. 

Drum brakes do not handle the heat from friction as well as disc brakes. They get hotter with repeated use, which makes them more prone to brake fade, a loss of stopping power when friction material overheats.

How do you know what type of brake is on your vehicle?

If you have disc brakes you don't have to take off the wheel to see them. You should be able to see an exposed brake rotor with a brake caliper covering part of the disc, if you look through your front wheels. 

The braking surface of a drum brake is not exposed, so you would only be able to see a solid metal drum.

Drum brakes were around before disc brakes so you may find them in older cars, and because they are lower in cost, some manufacturers use them on the rear of economy-priced vehicles to keep the price down.

It is important to note that, although disc brakes are more efficient and have better stopping power than the drum brakes, if properly maintained, either brake system is going to bring the car to a safe stop. 

If your car has drum brakes, you can give your vehicle an upgrade with a kit that allows you to replace the drum brakes with rotors and pads.