Physics

How do brakes in a car work?

The two most common types of brakes found in cars are either disc brakes or drum brakes. Cars also have hand brakes (also known as parking or emergency brakes), to keep the vehicle stationary.

Disc brakes slow the rotation of a wheel with friction, by pushing a pair of brake pads against a brake disc using a set of callipers. The brake disc is connected to the wheel of the car and/or it’s axle.

Below you can see a disc brake. The callipers are in red which are fitted around the disc brake inside the wheel.

disk brake

The friction causes the wheel to slow and stop, however also generates heat which can cause the brakes to become less effective.

Drum brakes also use friction, however they use a set of brake shoes or pads which expand against the inside of a drum to slow and stop the wheel.

A hand brake is used to keep a vehicle stationary, or to prevent the car from rolling when the driver needs to operate both the clutch and throttle pedals at the same time. The hand brake usually consists of a cable, connected directly to the vehicle’s brake mechanism on one end, and to a handle on the other for the driver to operate.