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.
This Article Contains:
- Drum Vs Disc Brakes: 3 Key Differences
- What Are the Pros and Cons of Using the Drum Brake System?
- What Are the Pros and Cons of Using the Disc Brake System?
- 5 FAQs About Drum Vs Disc Brakes
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.
What Are the Pros and Cons of Using the Drum Brake System?
Let’s first check out the advantages of using drum brakes for your vehicle.
Usually, drum brakes:
- Require less hydraulic pressure due to a built-in self-energizing effect
- Are somewhat easy to recondition
- Are affordable to manufacture and install
- Can easily house the parking brake mechanism
Unfortunately, drum brakes have a few significant disadvantages as well.
They:
- Allow heat build up in the drum during heavy braking because of their enclosed structure
- Can overheat easily and cause drum distortion, which in turn leads to vibrations while braking
- Involve several parts, which leads to more chances of failure
- Take more time to service due to their complexity
Next, let’s glimpse the upsides and downsides of using disc brakes in your vehicle.
What Are the Pros and Cons of Using the Disc Brake System?
Disc brakes are a fantastic addition to your car because they:
- Offer excellent stopping power
- Are less susceptible to rusting and degradation
- Experience less brake fade, leading to a more consistent disc braking force
- Less likely to lock up during heavy braking
Although brake technology has significantly improved, these brakes still have their own set of limitations.
Disc brakes:
- Are costlier to manufacture and install
- Are difficult to recondition
- Require a separate parking brake (a.k.a. handbrake or emergency brake) mechanism
Still confused about drum vs disc brakes?
Don’t worry.
We’ll now discuss the answers to the most commonly asked questions about drum vs disc brakes.
5 FAQs About Drum Vs Disc Brakes
Here are answers to five questions car owners frequently ask about drum brakes and disc brakes:
1. What Are the Critical Components of Drum Brakes?
A drum brake system has the following five key components:
- Brake drum: a large metal drum that rotates with your wheel and forms a frictional pair with your drum brake shoes.
- Brake shoe: a curved metallic block coated with friction material (a.k.a. brake lining) that rubs against the brake drum to generate stopping friction.
- Wheel cylinder: a cylindrical brake component with pistons inside that pushes the drum brake shoes outward as pressurized brake fluid is forced into it.
- Return or retracting spring: a steel spring that pulls the drum brake shoes away from your brake drum as soon as you release the pressure on your brake pedal.
- Self-adjuster: a small brake lever that maintains the gap between the brake shoe and drum to ensure they stay close enough when brakes aren’t applied but don’t touch each other.
2. What Are the Critical Components of Disc Brakes?
Disc brakes have three main components, and they are:
- Brake rotor: an iron, steel, ceramic, or carbon-ceramic rotating disc connected to your vehicle’s axle that turns along with the wheel.
- Brake pads: a brake component consisting of a metallic piece coated with friction material or brake lining that generates friction along with your brake disc or rotor to stop wheel movement.
- Brake caliper: metallic housing that houses your disc brake pads and pushes them against the wheel or brake rotor when you press down on the brake pedal.
3. How Do I Know Which Brake System My Vehicle Uses?
Most modern cars have disc brakes for the front wheels.
As for the rear brakes, you’ll either find a drum or a rear disc brake. Finding a rear drum brake in many cars may be more common for the rear wheel since they’re less expensive.
Why use disc brakes for the front wheels?
Usually, while braking, the weight of the car shifts forward. This means that you’ll need more stopping power on the front wheels. And since a disk braking system offers more stopping power, fitting disk brakes at the front is recommended.
Did you know many manufacturers use four wheel disc brakes for their high-end and performance models?
So, in case you want to check which category your vehicle’s front or rear brakes belong to, you can try taking a peek through the wheels:
- For drum brakes, you’ll see a large cylindrical drum almost touching the inside of your vehicle’s wheel.
- For disc brakes, you’ll see a flat rotor with a wider component (brake caliper) at the front or rear of your rotor.
4. What Are the Most Common Symptoms of Failing Brakes?
Whether your vehicle uses a drum brake assembly or a disk brake assembly, keeping track of its condition is critical to stay safe on the road.
If you notice any of these symptoms, it could be an indication that your drum or disc brakes are malfunctioning:
- The brake warning light gets activated
- Your brake pedal feels spongy or sinks to the floor
- There’s brake fluid leaking from your brake drum or caliper
- You experience inconsistent braking power while driving
- You hear grinding, rumbling, or squealing noises when you hit the brakes
- The brake lights on your vehicle won’t turn OFF
5. How Do I Maintain My Brakes?
Whether you’re driving a modern car or a scooter, you must always properly maintain your brakes.
Here are a few tips:
- Don’t overload your car
- Regularly flush brake fluid
- Use the one-foot method
- Slow down before braking
- Keep a safe following distance
Closing Thoughts
Disc brakes are more effective than drum brakes and are more durable, making them the preferred choice for newer vehicles. However, this doesn’t mean that drum brakes are going away soon. Their lower costs and the possibility for reconditioning make the rear drum brake a viable option for modern cars.
Irrespective of the type of brakes you may use, you need to keep them in check.
Fortunately, you can turn to AutoNation Mobile Service for this.
AutoNation Mobile Service is available 7 days a week, and we offer a 12,000-mile | 12-month warranty on all vehicle maintenance and repairs.
Just book your repairs online, and our expert technicians will come to your driveway to take care of everything!