Disc brake system

Distinguish disc brakes and drum brakes on cars

One of the most important systems in cars as well as vehicles on the road is the Brake System. There are many ways to classify the brakes, but in today’s commercial cars, the two most commonly used brake systems are disc brakes and drum brakes.

Image depicting disc brakes and drum brakes of cars

Disc brakes and drum brakes of cars
Disc brakes and drum brakes of cars

Depending on the purpose of installation, use and vehicle model, the brakes will be different. The main function of brakes is to reduce the speed of the vehicle by acting on the wheel while the vehicle is running. The brakes will use the friction created between the two surfaces to slow down to a complete stop.

Brakes on cars system

Basically, the brakes work based on the friction between two metal parts to reduce the speed of the vehicle. A rotating unit attached to the wheel hub and a stationary section containing brake pads. When the driver steps on the brake pedal, through the actuators, the brake pads will contact the rotating part, the friction between these two parts will help reduce the speed of the wheel.

Thanks to the brakes, the operator can slow down the vehicle, avoiding emergencies when there is a risk of bumping into other vehicles. Or avoid the bad situations that can occur when traveling on bad roads, .. Therefore, the brake has a very important role in the car.

Currently, automotive brakes include two main types: drum brakes and disc brakes.

1) What is a drum brake?

Car drum brakes system
Car drum brakes system

Drum brakes, drum brakes or clogs are called DrumBrake. Basically, they are composed of parts such as brake pads, brake pads, brake pads and a number of other parts that are responsible for transmission.

The drum drum is a hollow box structure and is fixed with the drive shaft, the inner surface of the drum is usually made of metal and has a rough surface to increase braking efficiency.

The brake pads are usually made from stainless steel, the surface of the brake pads will be covered with a layer of compound that has good friction resistance

In drum brakes, the brake pads work by means of hydraulic pistons or cables. They will create a sprung force to force the brake pads close to the brake drum. Compared with disc brakes or mechanical brakes, drum brakes have a much more complicated structure, and the durability is not really good, so this type of brake is often used only on ordinary cars.

parts of automobile drum brakes
parts of automobile drum brakes

Pros and cons of drum brakes


The cost of replacing and repairing is lower than that of disc brakes.
Simple structure, the parts are inside the drum, convenient for maintenance and repair.
The sealed design should be more suitable for climatic conditions, more difficult to break down.
Ability to enhance (suitable for trucks with large volumes).


Slow deceleration time means the car will take longer to stop.
The tight design makes poor cooling capacity, heat during operation cannot escape, use for long time reduces braking ability due to thermal expansion of components in brake structure.
Brake pads, brake pads, .. quickly wear out. This type of brake also generates a lot of heat and can suddenly lose braking.
Much heavier than disc brakes.

2) What is a disc brake? 

parts of automotive disc brakes
parts of automotive disc brakes

The disc brake is composed of a brake disc fixed on the rotating shaft and will move with the wheel as the vehicle operates. Typically, the brake disc will be punched or grooved, not flat, the purpose of the brake disc is to help optimize the cooling system.

In addition, the brake disc is also made from high-strength metals, good strength so it is very difficult to be damaged during vehicle operation. However, after a period of use, the surface of the disc will appear circular scratches due to friction with the brake pads (This situation will be more serious when the brake pads are worn out).

Meanwhile, brake pads will usually have 2 pairs installed symmetrically on both sides of the brake disc. When we proceed to squeeze the brake, the two brake pads will clamp the brake disc tightly, thereby making the car slow down. Because the contact surface between the brake pads and the brake discs is large, the braking ability of the disc brakes is more effective than drum brakes.

Disc brake system
Disc brake system

Pros and cons of disc brakes


Braking efficiency is much higher than drum braking due to high friction.
Open design should better dissipate heat, help maintain braking performance after a long time, minimize the risk of braking.
Open design will also help users, technicians easily observe, notice the damage to easily clean and repair.
Lower drum brakes weight -> reduced weight.

Defect: disc brakes of cars

Installation and replacement costs and repairs are higher than drum brakes.
Design the exposed disc brake disc and brake pads open so it is easy to stick to dust, dirt, sand … when operating. Must pay attention to hygiene to avoid damage costly replacement, repair
In unexpected situations, if the impact is too great on the brakes, the brakes will be tight and easily make the vehicle slip and flip.

The difference between disc brakes and drum brakes

For disc brakes, the rotating part is a metal disc (steel, carbon ceramic, …) attached to the wheel. The part containing the brake pads is the brake clamp (swine brake). The brake calipers also contain brake pistons so that when you step on the brake, through the brake mechanism, the pistons push the brake pads close to the brake disc to reduce the speed.

Car disc brake
Car disc brake

For drum brakes, all parts are contained inside the drum with wheels. The rotating part is the drum on the outside, the stationary part is a hydraulic cylinder mechanism, springs and brake pads (brake pads). When braking, through the actuators, the hydraulic cylinder pushes the two brake pads out and presses against the inside of the drum to create friction and reduce the speed of the vehicle.

Car drum brakes
Car drum brakes

At present, high-end sports cars use disc brakes thanks to the advantages of good performance and high aesthetics. Drum brakes often appear on trucks, passenger cars, and pickup trucks due to their specific characteristics on somewhat more complex terrain.

In addition, a large part of popular models are equipped with disc brakes for the front wheels and drum brakes for the rear wheels. Many people believe that this comes from the fact that current car manufacturers want to combine the two factors of braking performance and price. The front wheel uses disc brakes to increase safety of the vehicle during operation. Meanwhile, this system is not so necessary when used for rear wheels, drum brakes will be preferred to reduce costs and costs to consumers.

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