What Is a Disc Brake: Types and Working Mechanism Explained

Disc brake refers to the type of brakes where a pair of brake pads press against a disc rotor attached to the wheel to stop a moving vehicle. Bikes or four-wheelers have the disc brake system on its frontal or rear wheels. If you want to know what is a disc brake, let us take a look at what disc brakes are and how they work.

What Is a Disc Brake?

Disc brake refers to the type of brake that applies callipers for pushing a pair of pads to a disc or a "rotor" for generating friction. As a result, it reduces the shaft's rotating speed, either for lowering its speed or stopping it instantly. The name disc brake is due to the disc shape of rotor on which disc brake parts are attached.

When it comes to a conventional disc brake system, it has a brake disc, brake calliper and two friction pads. While your vehicle is in motion, these friction pads will fix on the exterior section of the disc to put on the brakes. Let's see how a disc brake works.

How Does a Disc Brake Work?

Before learning how a disc brake works, let's take a quick look at the three significant components of a disc brake. They are:

Brake or friction pads
Calliper, which includes a piston
Rotor, which attaches to the hub

Following are the pointers that will elaborate the working of disc brakes:

When you push a brake pedal, the high-pressure fluid of the master cylinder will thrust the piston outward.
The piston will allow the friction pads or brake pad to press against the rotating disc.
When the internal brake pad comes in contact with the rotor, immense pressure of the brake fluid applies pressure on the calliper.
In turn, the calliper drives inside and pulls down the external friction pad so that it can touch the moving disc.
When both brake pads exert pressure on the running disc, it generates huge friction between the disc and pad. This rolling friction reduces the speed of your car and enables it to stop.
If you release the brake, the piston will return to its earlier position, making the brake pad move away from the rotating disc. This is how your car will start to move again.

What Are the Types of Disc Brakes?

Since you have got the answer to what is a disc brake, let us learn about its types. There are three types of disc brake systems available. They are as follows:

1. Wave Disc Brake Systems

Another name for wave disc brakes is petal disc braking system. In this type of brake system, external boundary of the rotor is cut in a curved manner. This is done so that it can offer additional area for brake pads to grip the disc while it is rotating.

Moreover, due to its wavy design, it prevents rotor overheating. In addition, this disc is popular because of its lightweight and durability, which enables high acceleration.

2. Cross-Drilled Disc Brake System

The cross-drilled disc brake system has been a popular type of disc brake system for a really long time. It came into the picture for the first time in racing cars in 1960.

These discs have cross-drilled holes that enable it to avoid excess heat generated throughout braking and slowing down the vehicle. If you live in an area prone to rain, then drilled rotors will be an ideal choice.

Although cross-drilled disc brake system has some beneficial factors, there are few cases in which the rotating disc get damaged or cracked. This is probably because cross-drilled holes make the disc surface uneven.

3. Cross-Slotted Disc Brake System

A cross-slotted disc brake system has some narrow slots that cut on the disc surface. The pattern of these slots is not constant since their design varies from one model to another. Hence, these cuts can be of different widths and can have various angles.

Automobile manufactures of popular cruise bikes like Harley Davidson, Royal Enfield, Bajaj, etc. utilise these disc brake systems, Furthermore, cross-slotted disc brake system has the potential to disperse more heat since they are more efficient and heavy-duty than cross-drilled disc brake systems.

What Is the Construction and Mechanism of a Disc Brake?

common symptoms of bad brake disc — (source: carparts)

In a disc braking system, pushing the brake pedal will generate the braking force. This, in turn, will travel throughout the brake channel until it reaches the final brake disc rotor via springs, fulcrums, cylindrical rods, etc.

The disc or rotor rotates alongside the wheel, which are stopped by friction pads or brake pads. These pads are attached to the calliper from both sides that receive piston pressure once you press the brake. Therefore, when you push the brake, the piston will decelerate the disc movement, reducing vehicle's speed or stopping the vehicle.

What Are the Advantage sand Disadvantages of a Disc Brake?

Advantages and disadvantages of a disc brake are as follows:

Advantages

Better cooling brake system
Generates less heat
Brake force will remain intact even after it gets in contact with water
The disc brake has the potential to transmit huge torque in a small volume

Disadvantages

Disc brakes are unable to bear heavy load
Wheel rims get dirty too early
Disc brakes are too heavy as many components are used during their manufacture
It requires servicing very frequently
Usually somewhat more expensive

Now, that you understand what is a disc brake, you might want to install it on your vehicle. For this, you need to go through its types, benefits and drawbacks before making any decision.

Frequently Asked Questions

✓ Who invented disc brake?

British engineer Frederick W. Lanchester invented disc brake in the year 1902 for which he got a patent.

✓ How long do disc brakes last?

Although plenty of factors affect longevity of disc brakes, on average, this brake system lasts for approximately 50,000 miles.