When considering the differences between disc and drum brakes, what facts do car owners need to keep in mind? There are pros and cons associated with each braking system. Let’s take a closer look at both braking systems to give you a better understanding of disc vs. drum brakes.
A drum brake consists of a small round drum that contains pistons and two brake shoes. The drum rotates next to the car’s wheel. When the driver depresses the brake pedal, pressurized brake fluid is sent to the drum brake, and it forces the pistons to push into the brake shoes. This action causes the brake shoes to press against the sides of the drum, creating friction that slows the spinning of the wheel.
- Less expensive. Drum brakes are less expensive than disc brakes, and this cost difference is reflected in the price of a new car. All other things being equal, a car with disc brakes on all four wheels will cost more than one with disc brakes on the front wheels and drum brakes on the rear. Their lower price also makes drum brakes more affordable to maintain.
- Less effective at dissipating heat. The friction that comes with braking can create lots of heat. Relative to disc brakes, drum brakes do a poorer job of handling this heat, and they tend to get hotter with repeated use. This makes them more prone to brake fade.
- Less effective in wet conditions. In wet conditions, water has a tendency to pool inside drum brakes. This negatively impacts braking performance.
Disc brakes are made up of a brake caliper, two brake pads and a flat metal rotor that spins in tandem with the wheel. When the driver applies the brakes, the caliper squeezes the brake pads onto the rotor. This causes friction that slows the spinning of the wheel.
- Less brake fade. Disc brakes do a better job of managing heat than drum brakes. This causes them to experience less brake fade, which results in more consistent performance.
- Better performance in wet conditions. With disc brakes, the rotor repels water, and the brake pads wipe them away like a rag wipes water from a window. This allows disc brakes to deliver better performance than drum brakes in wet conditions.
- Less likely to lock up. Relative to drum brakes, disc brakes operate in a way that’s more linear and straightforward. This makes them less likely to lock up during heavy braking.
- More expensive. Disc brakes are more expensive than drum brakes. This impacts new-car pricing, and it also affects the cost of repairs.
A Matter of Cost
With most new cars, the front wheels handle most of the braking, so it makes sense that all new passenger vehicles come with front disc brakes. Some are also equipped with rear disc brakes, but rear drum brakes are commonly used in more affordable models.
If your car has drum brakes on all four wheels, you can give the vehicle an upgrade. Kits are available that allow car owners to replace drum brakes with those that have rotors and pads.
Overall, when you consider disc vs. drum brakes, disc brakes deliver better performance in both wet and dry conditions. But drum brakes offer cost benefits, and for this reason, they continue to be widely used.
Check out all the brake system parts available on NAPA Online or trust one of our 17,000 NAPA AutoCare locations for routine maintenance and repairs. For more information on disc vs. drum brakes, chat with a knowledgeable expert at your local NAPA AUTO PARTS store.
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I'm a writer and editor who's a regular contributor with the New York Daily News and Carfax, and my content has appeared in over 20 publications. I've written content that covers industries such as automotive, medical, insurance, healthcare, real estate, plumbing, pest control, dental and hospitality.