What are the two common types of brakes?
4 Answers
Brakes are divided into drum brakes and disc brakes. The comparison between disc brakes and drum brakes is as follows: In terms of cost: Drum brakes are cheaper than disc brakes, and disc brakes are less suitable for some special environments, such as areas with a lot of sand and gravel, where the brake discs are more prone to damage. In terms of heat dissipation performance: Disc brakes have excellent heat dissipation performance, and the braking system responds quickly, allowing for high-frequency braking actions. Compared to drum brakes, disc brakes have a simpler structure and are easier to maintain. Drum brakes have much poorer heat dissipation, and their braking force stability is insufficient, with significant variations in braking performance on different road surfaces, making them harder to control. Continuous braking may lead to brake fade and failure. In terms of brake pads: The friction area between the brake pads and the brake disc in disc brakes is smaller than that in drum brakes, resulting in less braking force. Additionally, the brake pads wear out more quickly and require more frequent replacement.
Disc brakes and drum brakes are the two most common types of brakes nowadays. I often watch auto repair videos. Disc brakes are the round discs you see behind the wheel hubs; they stop the vehicle by clamping the disc with brake pads, offering excellent heat dissipation and stable performance in rainy weather. Drum brakes are commonly used on the rear wheels of vans, resembling an iron drum hidden inside the wheel. When braking, the brake shoes expand to rub against the inner wall. My neighbor, a seasoned mechanic, mentioned that trucks prefer drum brakes for their strong braking force, though they dissipate heat more slowly, requiring caution during long descents to avoid heat fade. If you hear a metal scraping sound from the rear wheels, it's likely the wear indicator on the drum brake shoes signaling it's time for a replacement.
In our daily car repairs, we most frequently deal with disc brakes and drum brakes. The old Jetta we repaired last week had a front disc and rear drum setup. The brake pads of disc brakes are exposed, making them easier to replace—just a few pries during maintenance and it's done. Drum brakes are more troublesome; you have to remove the wheel and then the drum shell. If the drum shell is rusted, you even need a special puller to get it off. I remember last time a car owner drove hard into a water puddle, and the drum brakes made squeaking noises after getting waterlogged. It only stopped after draining the accumulated water. Actually, both types have their advantages: disc brakes are more responsive, while drum brakes are more durable. However, both are prone to getting sand or gravel stuck in the gaps, so it's best to rinse the wheel hubs a few extra times when washing the car.
Most family cars adopt a combination of disc and drum brakes. My SUV has ventilated disc brakes on the front wheels, which won't deform even under continuous braking, while the rear wheels use drum brakes with built-in parking brake modules. The biggest advantage of disc brakes is their linear braking performance, providing immediate feedback with gentle pedal pressure, and they quickly regain braking force after shedding water in rainy conditions. Drum brakes are more cost-effective, with replacement shoe sets costing just around a hundred yuan, though brake dust accumulates inside the drum and requires regular cleaning. For heavy-duty trucks, disc brakes wouldn't be suitable - large drum brakes are necessary to reliably stop those dozens-of-tons behemoths.
