In the automotive world, the braking system is of key importance for safety. For a long time, drum brakes were the standard, but today disc brakes dominate the majority of modern cars, especially on the front axle. This change is not accidental; it is the result of a number of significant advantages that disc brakes offer in terms of performance, reliability and efficiency, especially in more demanding driving conditions.
One of the most significant advantages of disc brakes is their ability to dissipate heat effectively. When braking, a huge amount of heat is generated from friction. With disc brakes, the brake disc (rotor) is exposed to air, which allows this heat to be quickly removed. In contrast, drum brakes are a closed system where heat accumulates inside the drum. Excessive heating leads to the so-called "brake fade", in which braking performance decreases dramatically, especially during prolonged or intense braking, which is a common problem with drum brakes.
In addition to better heat management, disc brakes provide more stable and predictable braking force. Their design allows for a more even distribution of pressure on the brake pads and disc. This results in shorter braking distances and better response in extreme situations. Drum brakes have a "self-boosting" effect, which can lead to uneven braking between the left and right wheels, as well as more difficult to dose the braking force.
Another important advantage is the better performance of disc brakes in wet conditions. Thanks to their open design, water and dirt are easily removed from the surface of the disc as it rotates. With drum brakes, water can get trapped inside the drum, significantly reducing braking performance until it evaporates or is drained away. This makes disc brakes more reliable in rainy weather or when driving through puddles.
Although they are more expensive to manufacture and initially install, disc brakes are often easier and faster to maintain. Replacing brake pads on disc brakes is a relatively simple process that does not require dismantling the entire drum and a complex mechanism. With drum brakes, replacing pads is more labor-intensive and often requires specific tools and adjustments. Additionally, disc brakes are more resistant to corrosion and contamination because they are more exposed to the air.
In conclusion, disc brakes offer superior performance compared to drum brakes, especially in terms of heat dissipation, fade resistance, wet performance, and predictability of braking force. They are a key element of the active safety of modern cars, allowing for shorter braking distances and greater control over the vehicle. Although drum brakes are still used on the rear axles of some cheaper cars due to their simplicity and cost, disc brakes remain the preferred choice for greater efficiency and safety.