The brakes in a vehicle are easily among the most important parts to its functioning. Despite most of the world having moved on to the more efficient disc brakes, older drum brakes are still in use in lots of modern cars. Below is a look at why that is the case.
First off, drum brakes are significantly cheaper. In a variety of applications, they also deliver higher efficiency. There was a time when these were used on both front as well as rear tires. While faster vehicles have driven many a manufacturer away from using these in newer models, drum brakes are still far from obsolete, owing to the following reasons.
Better Brake force
Compared to a disc brake of the same size, a drum brake provides much higher stopping power. This is a result of the higher contact area it forms between the drum and shoe, which is capable of slowing and halting the vehicle much more quickly than a disc brake setup. Drums brakes, being closed units, also allow for better braking under wet road conditions. This is because the contact patch stays protected from moisture, and drier surfaces produce significantly more friction.
Longer Service Period
A drum brake mainly consists of brake shoes capable of lasting over double the duration as a disk pad. In cars with a brake system setup consisting of a front disc brake and a back drum brake, the latter do little but apply sufficient stopping force to keep the vehicle from spinning. Meanwhile, the disc brake does the majority of the work, and as a result, incurs heavier damage with use. Drum brakes are also longer lasting because of another reason: the larger friction surface means it requires less force to bring about the same stoppage. That in turn means brake shoe wear is slowed considerably.
Lower Cost and Weight Advantage
Drum brakes cost a lot less, which means using them on the rear tires lowers production costs for the manufacturer. This is a huge reason why you still see a lot of care with rear drums brakes coming out, despite discs being so much more efficient and reliable.
An entire drum brake assembly has less weight than a rotor-caliper assembly of the same size does. Even adding a few brake accessories to the former would make the two even when it came to the overall weight of the vehicle.