What is the Difference between Brake Discs and Brake Drums?

Jan. 26, 22

Car Brake Discs and Drums

 

For many casual drivers, their idea of a vehicle's brakes is simply the pedal left of the throttle, and the expensive item that shows up on their service bill every few years. Never mind trying to ask whether they can discern between disc and drum setups. Fortunately, we “brake” down the differences between the two systems for you below.

 

Drum brakes

The first proper brakes on cars were the drum brakes, invented by French manufacturer Louis Renault in 1902.  A drum brake consists of a drum, a housing connected to the wheel, brake shoes, which are fitted in the housing and a master cylinder that is connected to the brake pedal. When the brake pedal is pushed the master cylinder causes the brake shoes to rub against the inside of the rotating drum, creating friction and ultimately slowing down the wheel to a complete stop. Drum brakes are used on many mass produced cars and on the rear wheels on more premium car models.

Advantages of Drum Brakes

  • Durability: Since drum brakes have an increased friction contact area, they last longer.

  • Low Cost: Drum brakes are cheaper to manufacture, hence they are more widely used on almost all types of vehicles.

  • Low Input Force: Some drum brakes require low input force to get them activated, meaning less push on the brake pedal, this can be done through various means like hydraulic pressure.

  • Low maintenance: Due to better corrosion resistance, as they are inside of a housing, they are slightly easier to maintain.

 

Disc brakes

People nowadays are most likely familiar with the disc brake system that has become increasingly ubiquitous over the last couple of decades. Rather than featuring a drum, disc brakes utilize a round rotor also made from cast iron, or in high-performance applications composites, including carbon and ceramic.

A “caliper” sits above and straddles both sides of the rotor, a part that contains a series of hydraulic pistons and a high friction brake pad on either side. Activating the brakes causes the pistons to clamp down and push the pads to make contact with the rotor, slowing down the vehicle. This is similar to what happens when braking on a bicycle.

Each time this process takes place, both the brake pad and the rotor wear away due to abrasive friction. Generally, the pads will be depleted sooner than the rotors and require more frequent replacement.

Advantages of Disc Brakes

  • Less Effort: Due to hydraulics as a standard on all disc brake systems, engaging a disc brake requires less effort and produces greater braking force.

  • Heat Dissipation: Due to the large surface area of discs any heat produced by the friction of the brake pads on the disc dissipates into the atmosphere. This prevents overheating of the disc and improves braking even infrequent hard braking situations.

  • Standard Performance In Any Weather: Disc brakes perform well even in wet conditions and don't slip or grab like their drum counterparts.

  • Easy Installation: A disc brake has a few components and is hence very easy to install, even you can learn how to change the brake pads on your discs.

 

Other differences                                                            

Because of its enclosed design, drum brakes are prone to excessive heat build-up under high-stress situations, which can cause “fade,” meaning the brakes start to lose their effectiveness. The rotors used in disc brakes on the other hand are exposed to ambient air resulting in constant cooling.

Cost of manufacturing is one of the reasons some automakers continue to offer partial drum brake setups. That said, the front brakes do the majority of the work since weight is shifted forward each time you brake, so only having discs in the front is more than adequate for most motorists.

 

Replacement

The life of brake components varies greatly depending on models, personal driving habits, and driving conditions — the best thing to do is take your vehicle in for regular servicing to ensure everything is working properly. If you hear or feel anything out of the ordinary like squealing or shuddering when the brakes are applied, make sure you consult a professional immediately or contact Kamien.

If you need, you can contact us directly!

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