Drum vs Disc Brakes: How Do They Differ? (+ Pros & Cons)

If you were to peek behind your wheels, would you be able to tell if you had disc or drum brakes?

And besides appearance, how else are drum vs disc brakes different?

We’ll start the discussion by comparing the drum brake system against the disc brake system, then cover their pros and cons. Later, we’ll answer five FAQs about drum brakes vs disc brakes to give you a clear understanding of each braking system.

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Let’s get right to it.

Drum Vs Disc Brakes: 3 Key Differences

Although both the drum and disc braking systems slow down your moving vehicle by generating friction, there are some key differences between the two, like their:

A. Method of Braking

Both drum brakes and disc brakes use hydraulic mechanisms to generate braking force.

When you push down your vehicle’s brake pedal, a piston inside the master cylinder compresses brake fluid and transmits it to points near your wheels via brake lines.

The pressurized hydraulic fluid forces the pistons inside the wheel cylinder outwards in a drum braking system. These pistons, in turn, push a set of drum brake shoes against the brake drum to generate friction, slowing down your vehicle.

On the flip side, your vehicle delivers the pressurized hydraulic fluid to a brake caliper in a disc braking system. The brake caliper then squeezes a set of disc brake pads (a.k.a. friction pads) against the brake rotor (a.k.a. wheel rotor or brake disc), generating friction to halt wheel movement. 

B. Braking Power

Your rotating disc brakes are constantly exposed to the atmosphere, so they can quickly dissipate the heat generated during braking.

But since drum brakes are closed (not exposed to air), heat dissipation would be much slower. This can cause brake fade — a loss in braking power due to overheating from inefficient heat dissipation.

The disc brakes’ exposure to the air outside also means it’ll work better in wet conditions.

How?

Since a disc brake is open to the atmosphere, it can quickly sling off any moisture accumulated while driving. Moreover, the brake or friction pads rubbing against the wheels can also wipe away any water, just like your wiper blade wipes the water off your windshield.

However, moisture might get trapped inside the drum and take more time to dry in drum brakes, impacting braking performance. The moisture can affect the frictional force your brake shoe and brake drum pair generate, compromising braking power.

C. Brake Maintenance Needs

Disc brakes are self-cleaning.

Remember, your brake pad wipes the rotor when engaged. This usually removes any debris clinging to the wheel or brake rotor.

On the other hand, since drum brakes are generally closed, they’re prone to accumulating the brake dust generated by the drum brake shoes. If the brake dust accumulated becomes excessive, your braking performance may decline.

As a result, you’ll need to clean and service your drum brakes more often than disk brakes to ensure optimum brake performance. Additionally, since your drum brakes include more components, they’re usually more challenging to service.

Now that you know the critical differences between drum brakes and disc brakes, let’s move on to the pros and cons of each of these brakes.