What are Disc Brakes

What Is Disc Brakes & How They Work

Did you know most of the modern cars use disk brakes for their braking system? Disc brakes are safer than any other braking system because they excel at stopping vehicles, even when you are at a significant speed! 

Their braking power is top-notch. That’s why they are more popular than drum brakes and are used in most vehicles. So, you might wonder, What is Disc Brakes?

A disc brake is a braking system that works by using calipers to press brake pads against a spinning disc or rotor. This contact generates enough friction to slow down the rotation of the car’s axle. Which eventually decreases the vehicle’s speed or stops it completely.

In this article, we will inform you about the function of disk brakes and the types of disk brakes that exist, as well as the pros and cons of disk brakes.

So, let’s dig deeper and know more about it.

Components of a disk brake?

Before jumping onto the function of the disk brake, let’s know about the component it holds. A disk brake system consists of several components, and they are:

Rotor (Disc): The disk, also known as the rotor, is a flat, rounded metal disc attached to the wheel hub. It is usually crafted from either cast iron or a combination of steel and cast iron. When you apply the brakes, the brake pads make contact with the rotor(disk), which creates enough friction to slow down the wheel’s rotation.

Brake Caliper: The brake caliper is a metal piece that holds the brake pads and compresses them against the rotor(disk) when you apply the brakes. It’s mounted over the rotor and contains pistons that move when hydraulic pressure is applied.

Brake Pads: These are flat, rectangular plates with a friction material on the inner side. They are positioned on each side of the rotor within the caliper. When you press the brake pedal, the caliper pushes the pads against the rotor, which generates friction and slows down the wheel eventually.

Pistons: The pistons are mounted inside the brake caliper, and they are made sure to be sealed to prevent any brake fluid leakage. When you push the brake, hydraulic pressure is generated to slow down the wheel, which pushes the pistons external surface with hydraulic pressure. This pressure forces the brake pads to make contact and friction with the rotor.

Types Of Disc Brakes

Based on the caliper, two types of disk bakes are available: Floating rotor and Fixed or solid rotor. Let’s know how they differentiate from each other.

1. Floating rotor

The most common type of brake caliper used in cars nowadays is the floating caliper, also known as a sliding caliper. It usually has one or two pistons. 

When you press the brakes, the inner brake pad pushes against the disc, and at the same time, the caliper body moves closer to the rotor. This movement causes the outer brake pad to make contact with the rotor as well.

2. Fixed or solid rotor

In a fixed caliper design, the caliper stays still and doesn’t move. It’s firmly attached to a bracket or spindle. There are one or more pistons on each side of the rotor. 

When you press the brakes, only these pistons move, pushing the brake pads against the disc to slow down the wheel.

How Does A Disk Brake Work?

Floating disc brakes are commonly found in modern vehicles and are also popular in motorsports. So, we will focus on the widely used floating disk brake, and let’s take a closer look at how it works. 

The brake disc or rotor is the most crucial part, which makes it different from other braking systems. It is divided into two sections with small holes to dissipate as it generates too much heat due to friction.

The disk brake works in a straightforward way. When you press the brake pedal, the hydraulic pressure from the master cylinder pushes the piston forward. Then, the piston passes the pressure forward and pushes the brake pad against the rotating disk.

As this happens, the inner pad comes into contact with the rotor. The fluid pressure adds more force, causing the caliper to move inward. This action brings the outer brake pad closer to the spinning disc until it makes contact.

So now both the pads are pushing the rotating disk, and as a result, they create a large amount of friction, which slows down the car and eventually makes it stop.

When you stop pressing the brakes, the pressure is released, the piston moves inward, and the brake pads move away from the rotating disc (rotor). So, the vehicle starts to move again.

This video will help you gain a better understanding of disk brakes

Disc Brakes Vs. Drum Brakes: What’s The Difference?

Based on their function, there are 3 major differences between disk brakes and drum brakes. Let’s know how they are different from each other:

1. Difference Between How The Brakes Work

Both drum brakes and disc brakes use hydraulic pressure to make your car stop.

At first, the hydraulic system kicks in both of the braking systems; when you press the brake pedal, it pushes a piston in the master cylinder, which compresses the brake fluid. 

Then, this fluid goes through brake lines to points near your wheels.

In a drum brake system, this pressurized fluid pushes out pistons in the wheel cylinder. These pistons push brake shoes against the brake drum, which creates friction and slows down your car.

In a disc brake system, the pressurized fluid goes to a brake caliper. The caliper squeezes brake pads against the brake rotor, which creates friction to slow down the wheel.

2. Braking Power

As we know, brakes can generate enormous heat due to friction, and they need to dissipate heat to function properly and avoid brake fade.


Disc brakes have built-in cooling holes, so they are always exposed to the air so that they can cool down quickly after braking.

On the other hand, drum brakes are confined from all sides with no ventilation. Thus, they cool down more slowly. This massive heat can lead to forming gas and brake fade, which means it is a phenomenon that reduces braking power due to overheating.

Disc brakes also work better in wet conditions because they can shake off moisture through ventilation holes while driving. Just like your windscreen wipers, the pads also do the same to remove access moisture by rubbing against the wheels to help get rid of most of the water.

Drum brakes do hold onto moisture longer, which is a hindrance to their performance. This moisture can affect the friction between the brake shoe and drum, making the brakes less effective.

3. Brake Maintenance

In the case of maintenance, there are also differences between disk and drum brakes.

Disc brakes are easier to maintain because, as we said, they clean the moisture themselves by rubbing against the rotor. Which also helps to get rid of any debris.

Drum brakes, being confined from all sides, tend to collect brake dust created by friction from the brake shoes. If there is too much dust built up, your brakes will lose their effectiveness.

That being said, we can see drum brakes need frequent maintenance to get rid of debris and moisture and are more prone to failure than disk brakes.

However, there are also some nitpicky pros and cons about disk brakes being mostly used mechanism. We will now look into that.

Pros and cons of disk brakes

Pros:

Disk brakes offer more advantages than any other braking system. The pros of disk brakes are

  • Because of proper ventilation, they can dissipate heat faster and avoid brake fades.
  • They offer far more effective braking power than any other braking system.
  • Self-cleaning the rotor with brake pads makes it debris and moisture-free, so they are less likely to rust.
  • Less prone to lock up of heavy braking than other brain systems.

Cons:

Although disk brakes offer far more advantages than other braking systems, there are still some disadvantages of disk brakes. The cons of disk brakes are

  • Costlier to manufacture than any other brakes and expensive to replace and install.
  • Difficult to recondition and repair
  • Disc brakes wear out faster than drum brakes because the brake pads in disc brakes tend to get used up more quickly.
  • Has skidding issue in wet conditions
  • Improper placement can cause warp in the rotor or disk

Final words

Disk brakes are becoming popular due to their safety and convenience, as they are also being upgraded through different methods and gaining popularity in motorsports too.

This makes disc brakes the most widely used braking system, and most modern vehicles come with disc brakes, which has the possibility that your car is equipped with disk brakes too.
Hope now you have a proper answer to your question,” What is Disc Brakes?” and you can check our other articles about brakes

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