Automobile braking technology has come a long way since Louis Renault popularised drum brakes in the early 1900s. Drum brakes were initially popular for their reliability and cost-effectiveness but have been largely replaced by disc brakes in modern vehicles. Disc brakes are known to perform exceptionally well under high-risk conditions. While not very popular initially, disc brakes have proven their effectiveness with time. The usage of disc brake or drum brake has a significant impact on your vehicle’s performance. Let us understand in detail - how they differ, their working mechanism, and their advantages and limitations.
What is a Drum Brake?
A drum brake system is a traditional braking mechanism that plays a vital role in vehicle safety. The most important parts of a drum brake system are:
- Drum: It is a rotating cylinder attached directly to the wheel. It acts as the outer shell within which all other brake components operate.
- Brake Shoes: These are curved pads with friction material on one side. Hydraulic pressure drives the shoes outward against the inner surface of the drum when you push the brake pedal.
- Brake Drum Housing: This houses the brake shoes and is connected to the wheel assembly. It remains stationary as the drum rotates with the wheel.
- Master Cylinder: It is a critical part of the brake’s hydraulic system. When you press the brake pedal, it pushes hydraulic fluid to the brake shoes. This causes them to expand and create friction against the drum, which in turn slows down or stops the vehicle.
Advantages of Drum Brake
Drum brakes are a reliable option for vehicles that are not driven on rough or unsafe routes. Here are the main advantages:
- Durability: Drum brakes wear down more slowly due to a larger friction contact area with the brake shoes. This extends their lifespan compared to disc brakes.
- Cost-Effectiveness: Drum brakes are economical to produce and install. Hence, they are a popular choice for budget vehicles. Their make and design reduce initial costs and maintenance expenses.
- Low Input Force: They require less force for effective braking due to the mechanical advantage of their design. This makes them easier and more comfortable to use during regular driving.
- Ease of Maintenance: The enclosed design protects internal components from dust and water. This significantly lowers the maintenance.
- Consistent Performance: Drum brakes are reliable in all weather conditions. They maintain adequate stopping power in moderate and extreme climates.
Disadvantages of Drum Brake
Drum brakes have some disadvantages that impact a vehicle's performance in certain conditions. They are:
- Heat Accumulation and Brake Fade: Drum brakes can overheat due to their enclosed design, which lacks efficient heat dissipation. This overheating can lead to brake fade as the brake shoes glaze and harden under high temperatures.
- Increased Pedal Effort: When overheated, the drum expands slightly. This means you need to press the brake pedal harder to achieve the same braking effect. This can be problematic during emergency stops when rapid braking is needed.
- Grabbing: Drum brakes are prone to “grabbing” when the brake shoes become wet or rusty. This causes uneven and potentially dangerous braking, especially at higher speeds.
- Maintenance Complexity: The multiple components within the drum, such as springs and adjusters, make maintenance challenging and time-consuming. They require regular maintenance to avoid problems like sticking or squealing.
- Reduced Effectiveness in Wet Conditions: Water can enter the drum and reduce the friction between the brake shoes and the drum. This diminishes braking power in wet conditions.
What is Disc Brake?
Disc brakes are a more advanced type of braking system that has become the standard in modern vehicle design. The key components of a disc brake system include:
- Rotor: The rotor is the circular disc that spins with the wheel. It is the surface against which the brake pads compress to create friction and slow the vehicle.
- Calliper: The calliper fits over the rotor and houses the brake pads and pistons.
- Brake Pads: These are fitted within the calliper and press against the rotor when the brake is applied.
- Piston: The piston is located inside the calliper. It pushes the pads into the rotor when hydraulic pressure is applied through the braking system.
Hydraulic fluid forces the pistons to extend when the brake pedal is pressed. This presses the brake pads tightly against the rotor. This action generates friction, which reduces the speed of the vehicle. The force exerted by the disc brake is significantly more direct and powerful than that of drum brakes. This results in quicker and more reliable stopping.
Advantages of Disc Brake
Disc brakes are favoured for their exceptional performance and advanced mechanism. Here are some other advantages:
- Efficient Heat Dissipation: The open rotor design of disc brakes allows for superior air circulation and heat management. This rapid heat dissipation is crucial during high-speed driving or frequent braking. It prevents brake fade and improves performance and longevity.
- Enhanced Braking Force with Less Effort: The hydraulic systems in disc brakes reduce the effort needed from the driver while increasing braking force. This ensures powerful and confident braking with minimal pedal pressure.
- Reliable Performance in Various Conditions: Disc brakes perform consistently in diverse weather conditions. Their design prevents water retention, reduces the risk of slipping, and maintains an effective grip even on wet roads.
- Ease of Installation and Maintenance: Disc brakes have a simpler and more accessible configuration, which makes them easier to install and maintain. With fewer parts to manage, routine maintenance can be performed quickly and cost-effectively.
Brake Fade
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More susceptible due to heat build-up.
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Less susceptible, maintains performance under stress.
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Stopping Distances
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Generally longer, suitable for moderate use.
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Shorter, providing superior stopping power.
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Maintenance
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Requires periodic adjustments.
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Less frequent need for service.
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Weight
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Heavier and affects fuel efficiency and dynamics.
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Lighter and contributes to better handling and efficiency.
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Performance in Wet
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Slightly less effective; can trap water.
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More effective; quickly sheds water.
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Noise
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Produces less noise during operation.
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Can produce more noise, especially if worn.
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Corrosion
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Generally less susceptible to corrosion.
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More vulnerable to corrosion in rotor and calliper.
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Brake Dust
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Generates less brake dust.
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Produces more brake dust.
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Complex Components
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Simpler design with fewer moving parts.
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More complex with callipers, pistons, and rotors.
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Price
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Typically more affordable in both initial cost and maintenance.
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Generally more expensive to install and maintain.
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Parking Brake
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Integrated parking brake mechanism is more common.
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Parking brake functionality may vary; sometimes needs additional components.
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