Skip to content

How Disc Brake Work? – Best Explanation

Here you can get Disc Brake Working Principle. Disc brakes have been widely used in both heavy vehicles and passenger cars, despite the fact that drum brakes are predominantly used in trucks and buses.

What Is Disc Brake

A disc brake is a type of brake that uses the calipers to squeeze pairs of pads against a disc or a “rotor” to create friction. This action slows the rotation of a shaft, such as a vehicle axle, either to reduce its rotational speed or to hold it stationary. Disc brakes are mostly used in motorcycles and cars.

Disc brake system is widely used on front wheels in mid-range two-wheeler such as – commuter & sports bikes. The Disc brake system is used on the front wheels of most hatchback cars, entry-level sedans & MUVs; whereas, it is also widely used on both front & rear wheels of high-end cars and SUVs in combination with hydraulic / vacuum brake actuating systems.

Main Components of Disc brake

1. Wheel Hub: The disc rotor is attached to the wheel hub and it rotates with it. The wheel of the vehicle is bolted to the wheel hub.

2. Caliper Assembly:

The caliper assembly consist of

  • Brake pad: It makes contact with the rotor disc and because of the friction among the brake pad and rotor disc the vehicle speed reduces and it stops.
  • Caliper bracket
  • Caliper frame
  • Piston: It applies the brake pressure at the brake pads while brake lever is pressed.
  • Slider pin: It is the sliding pin which slides in the hole when brake is applied.
  • Dust boots: It prevents the entry of dirt into the caliper pin or slider pin hole.

3. Disc Rotor: It is the rotating a part of disc brake. When brakes are applied, lots of warmness is generated which can lower the braking efficiency, so the rotor has drilled vent holes on it which dissipates the heat.

Working Principle

The working of a disc brake is based on Pascal law.

  • When the brake pedal is pressed, the excessive pressure fluid from the master cylinder pushes the piston outward.
  • The piston pushes the brake pad against the rotating disc.
  • As the internal brake pad touches rotor, the fluid pressure exerts further force and the caliper movements inward and pulls the outward brake pad towards the rotating disc and it touches the disc.
  • Now each the brake pads are pushes the rotating disc, a large amount of friction is generated in among the pads and rotating disc and slows down the automobile and finally let it stop.
  • When the brake pad is released, the piston movements inward, the brake pad moves away from the rotating disc. And the automobile once more starts to move.

Types Of Disc brakes

There are types of disc brakes. One is known as the “opposed piston type disc brake” which has pistons on each aspects of the disc rotor, and the alternative is the “floating type disc brake” which has a piston on only one side. The floating type disc brakes also are known as the sliding pin type disc brakes.

Opposed Piston Type Disc Brakes

The opposed piston type is a disc brake which has pistons on both sides of the disc rotors. The opposed piston type disc brake features stable braking pressure in addition to a excessive degree of controllability. The swept regions of the brake pads are enlarged to growth braking pressure, and here opposed piston types are favored.

This is due to its benefit in which the number of pistons may be expanded to realize even distribution of pressure on the rotors from each aspects. Depending at the length of the brake pads, there are several types, including the 4-pot type which has pistons on every aspect for a complete of four, and the 6-pot type which has 3 pistons on every aspect for a complete of six.

Floating Type Disc Brakes

Floating type is a disc brake which has a piston on only one side and is also called the sliding type disc brake. On the floating type disc brakes, the piston pushes the internal brake pad towards the rotor when the brakes are engaged. This generates a reaction pressure that actions the caliper itself at the side of the slide pin, pushing the outer pad towards the rotor to clamp it from each sides.

Many passenger automobile disc brakes are of the floating caliper type since this type has a relatively simple and lightweight construction, which permits for decrease production costs.

Floating type disc brakes for commercial vehicles Disc brakes are used specifically for passenger cars, but due to their consistent overall performance at better speeds and resistance to brake fade, they are gradually spreading into the commercial vehicle segment, in which drum brakes were traditionally chosen for their resistance towards wear.

Advantages of Disc brake system

  1. No adjustment required. So, no maintenance.
  2. Better stopping performance
  3. Fade-free braking in all conditions. So, no fading of brakes.
  4. Can test wear without dismantling the unit
  5. Easy & quick to alternative of pads in comparison to Drum brakes

Disadvantages of Disc Brake system

  1. High braking force needed compared to Drum brake
  2. Low life of brake pads compared to brake shoes
  3. Need separate hand-brake mechanism when fitted to rear wheels
  4. It is difficult to attach a suitable parking attachment.


  • Disc brakes are mostly used in motorcycles and cars.

Leave a Reply