At first, both drum brakes and disc brakes seem similar. They both stop the car by applying friction to the rotating wheel which slows and eventually stops it. Both use pads and are fairly common, but each has different perks and work in a slightly different way.
Drum brakes consist of a round metal cylinder that is part of the wheel, called the drum, and a series of pads which are fixed inside the drum. When the brakes are applied, this pad pushes outward from inside the drum and creates the friction needed to slow the vehicle. Drum brakes are more compact, less expensive to produce, and easy to replace. For the most part, drum brakes work pretty well. The downside of them can be seen in extreme conditions where heating of the pads and cylinder causes expansion and loss of brake efficiency because heat dissipates more slowly from the enclosed system.
Disc brakes consist of a round flat disc that is attached to the wheel and an exterior clamp that presses down onto the disc to provide stopping friction. The advantages of this setup are its open-air design. Heat can dissipate easily and thus expansion of the pad and metal is less of a concern. Disc brakes also have better stopping power than drum brakes. They’re more expensive to produce and maintain though.
You’ll often find both types of brakes on a car with disc brakes on the front wheels and drum brakes on the back ones. When you stop, the bulk of the work will fall to the front tires where all the force will be distributed which is why the disc brakes with higher stopping power are placed there.
If you’re interested to learn more about brake types, visit us at Mama's Used Cars and we’ll be glad to answer any questions.