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Difference between drum brakes and disc brakes: which are better?
First of all, let’s look at the similarities between the two. They both operate on the same basic principle: the brakes slow the car wheels down by turning kinetic energy into heat through friction. The key difference lies in how the components create friction and their braking efficiency.
The first drum brakes were patented in 1902 by French automotive pioneer Louis Renault. They laid the foundations for today’s modern braking systems and were the main type of brake for cars until disc brakes were popularised in the mid 1950s. In modern car front and rear drum brakes components are: hydraulic wheel cylinders, brake shoes, springs, and the brake drum. When you press the brake pedal, two brake shoes are pushed against the inner surface of the rotating drum by the wheel cylinders, slowing the vehicle’s momentum. Once the brakes are released, the retracting springs draw the shoes away from the drum.
Instead of housing the parts of car brakes inside a metal drum, disc brakes work using a slim metal disc and calipers containing brake pads and pistons. When you engage the brakes, the main hydraulic cylinder pushes hydraulic fluid through the brake lines, actuating the pistons. The pistons press the friction pads against the rotating metal discs, creating friction and forcing the discs and wheels to slow down. Discs have become the standard in the car industry due to their efficiency and heat dissipation advantages. However, most manufacturers still use a combination of the two types - discs on the front axle and brake drums at the rear.
BREMBO Brake disc
295x28mm, 5, perforated/vented, Coated, High-carbon
ATE Brake caliper
red, Aluminium, without holder
QUICK BRAKE Bolt, brake caliper
M16x1,5
BREMBO Brake pad set
incl. wear warning contact, with brake caliper screws, without accessories
BREMBO Brake disc
324x22mm, 5, internally vented, slotted/perforated, Coated, High-carbon
The advantages and disadvantages of drum brakes
- Low cost. Although they are generally considered to be less efficient than disc brakes, they are also less expensive to produce and are therefore used on most types of vehicles.
- Low maintenance. The components inside the drum have a high resistance to corrosion which means they need to be maintained less frequently.
- Require less pressure. The required pressure to activate the brakes is fairly low. The “self-energising” effect of the drum increases the stopping power without any additional effort.
- Durability. They can last a long time as they have a larger friction surface contact area than discs.
- Overheating. They tend to overheat in heavy braking or high speed conditions, causing the drum to distort and shoes to glaze.
- Grabbing. Can occur when the components get wet or rusty, causing tyres to skid.
- Thermal expansion. The diameter of the drum can increase, meaning that the driver has to press the pedal further.
BREMBO Brake disc
390x36mm, 5, internally vented, slotted/perforated, two-part brake disc, Coated, High-carbon
BREMBO Brake disc
345x24mm, 5, internally vented, slotted/perforated, two-part brake disc, Coated, High-carbon
BREMBO Brake caliper
Grey Cast Iron, behind the axle, Front Axle Right
BREMBO Brake disc
240x11mm, 4, solid, Perforated, Coated
TRW Carrier, brake caliper
The advantages and disadvantages of disc brakes
- Heat dissipation. The components are exposed and have a large surface area, allowing the heat from the discs to dissipate into the atmosphere and preventing overheating.
- Better performance in all weather conditions. They are even efficient in wet conditions and don’t grab or slip like drum brakes.
- Easy to install. There are fewer components and they’re fairly easy to disassemble. For example, you can easily replace the brake pads on your car yourself.
- Expensive. More expensive to manufacture than drums.
- Wear. The discs and pads provide more stopping power but tend to wear out much faster.
- Warping. The discs can warp at high speed braking due to extreme temperatures.
Need to replace your brakes?
If you notice squealing or grinding sounds when braking, or find it difficult to maintain control of the vehicle, it could be time to replace the braking components. Whether you’re looking for BMW brake discs or brake drum parts for your Renault, you can find braking system parts at very low prices online.