Disc vs. Drum Brakes
At a Glance
Disc brakes are prized by high-performance car enthusiasts due to their ability to apply a high amount of brake force and dissipate heat quickly. However, lower cost makes drum brakes the typical choice for at least two of the wheels in a standard commuter car.
When buying a vehicle or taking your existing vehicle for repair the subject of brakes will arise. The type of brake on each wheel affects how your car performs and you need to know what to look for. The two main contenders are disc brakes and drum brakes. We are going to go through what these mean and explain how they differ. Many modern cars have disc brakes on all four wheels but some cars use drum brakes for the rear wheels. If you need to decide between disc vs. drum brakes, which one do you choose?
Briefly, the drum brake is much older dating back to 1908 with disc brakes not seeing common use until the mid to late 1940’s. A drum brake consists of brake shoes within a rotating metal drum. Force from the driver is used to push the brake shoes onto the drum using friction to slow down the vehicle. Alternatively, the disc brake is made up of a rotating disc with a brake caliper that squeezes both sides of the disc when pressure comes from the driver. Both systems use brake pads; these are the resistant surfaces pushed against the drum or disc.
When it comes to disc and drum brakes there is really one deciding factor on their use; it usually boils down to price. Drum brakes are the cheaper of the two and as a result get used when possible. In many modern cars you may find disc brakes at the front and drum brakes on the rear. This is simply to keep the costs down; the rear brakes do not need to apply as much force as the front brakes so drum brakes can help save money. Cars with disc brakes on all wheels will be performance cars with heavier price tags to match. Both have their place in the market, and your budget will be the greatest determining factor in the type of brakes with which your car is equipped.
As mentioned above, drum brakes tend to be used when less braking force is required. You can guess then that disc brakes are a superior product. The main issue at stake is “brake fade.” When the brake is in operation it generates a great deal of heat. In a drum brake there is no real airflow because the mechanism is all contained within the drum. This causes the components to heat up drastically and reduces their effectiveness. A disc brake is better ventilated so fade does not happen as quickly. When left to cool, the heat also dissipates more quickly from disc brakes. Brake safety is very important so having your brakes working at their optimum capacity whatever the temperature is vital.
Brakes are there for safety. It is important that whatever brakes you have you know how to check them and how to know they’re due for servicing. On the whole, disc brakes are easier to repair than drum. The simple reason for this is that you get better access to the parts. You can check and replace them quickly. If a disc fails on a disc brake for example, you can just replace that component and it will be a quick job for a professional. If a drum on a drum brake goes wrong then there is a good chance the whole unit will need replacing. This is obviously more expensive. If you ever hear a scraping noise when braking, it’s likely that your brake pads need to be replaced. Do this immediately to avoid causing further damage and more expensive repairs.
A good set of brakes, whatever their design, are a good investment. Modern technology is advancing more towards disc brakes as the standard but good rear drum brakes are equally valid in basic commuter cars.
Picture courtesy of Ford.