How Should The Braking System Be Configured for A Quieter Car?

Vehicle noise significantly impacts the driving experience, with the brake system (brake pads, brake discs, brake drums) and clutch system (clutch plates) often contributing the most noticeable noise. Achieving a near-silent driving environment requires a scientific approach, encompassing component materials, structural design, and system integration. This article will introduce a detailed approach.

I. The Core of Braking System Noise Reduction

Brake noise primarily stems from frictional vibrations between the brake pads and the brake disc (or drum). This requires optimization in terms of material softness and contact smoothness:

1. Brake Pads: Prioritize materials with low hardness and high damping.

• Ceramic Composite Brake Pads: Containing ceramic fiber, graphite, and rubber, these pads have a low friction surface hardness (60-70 Shore A hardness), minimizing impact when in contact with the metal brake disc and reducing "high-frequency squeal." Their internal rubber particles absorb vibration energy, making them the optimal choice for quieter driving, particularly suitable for urban commuting.

• Organic Silent Brake Pads: Made with a resin and Kevlar fiber base and lubricated with silicone oil, they offer a "soft touch" feel during braking and are 15-20dB quieter than semi-metallic brake pads. However, be aware that they have poor heat resistance and are not suitable for high-intensity braking situations involving frequent, hard braking.

• Pothole Avoidance Tips: Avoid high-metal content brake pads (over 50% metal). Excessive hardness can easily create "rigid friction" with the brake disc, especially at low temperatures, leading to harsh noises.

2. Brake Discs: Structural Design Reduces Vibration and Resonance

• Ventilated Slotted Discs: Radial grooves on the disc surface break the "resonance frequency" of the friction surface, while ventilation holes quickly dissipate heat, preventing hardening and noise caused by high temperatures. When paired with ceramic brake pads, braking noise can be kept below 60dB (equivalent to a normal conversation).

• Low-Metal Alloy Discs: Made of cast iron and copper/nickel alloy, they are tougher than traditional gray cast iron discs, effectively absorbing the friction impact of the brake pad and reducing "metallic knocking" noise. Suitable for family cars that demand both quietness and durability.

3. Brake Drum: Internal Noise Reduction with a Closed Structure

Drum brakes are prone to producing low-frequency hum due to their enclosed structure. Therefore, the key focus is on the proper fit between the brake shoe and the drum:

• Curved Silent Brake Shoe: The friction pad features a graduated hardness design (harder at the edge than at the center). This allows for gradual contact with the brake drum, preventing sudden, rigid impact.

• Internal Drum Damping Coating: A 0.5mm thick layer of high-temperature-resistant damping rubber is sprayed onto the inner surface of the brake drum to absorb vibration energy during braking, particularly suppressing "buzzing" noise under heavy loads.

II. Key to Clutch System Noise Reduction

Clutch noise in manual transmission vehicles often comes from friction or impact when the clutch plate engages and disengages. Therefore, the design must balance "soft contact" with "precise synchronization":

1. Clutch Plate: Reduces engagement impact and sliding friction noise.

• Resin-Based Silent Clutch Plate: Nitrile rubber particles are added to the friction surface to cushion the impact between the pressure plate and flywheel during engagement, reducing "clicking" noise during engagement. At the same time, its friction coefficient is stable, and sliding noise in the semi-clutch state is 30% lower than that of metal-based clutch plates.

• Clutch plate with damping spring: 3-6 micro springs are embedded between the clutch plate steel plate and the friction plate to absorb torsional vibration, making it particularly suitable for noise reduction in diesel vehicles (which experience high engine vibration).

2. Release mechanism: Reduces mechanical transmission noise

• Hydraulic release bearing: Replaces the traditional cable-type release mechanism, transmitting power through hydraulic oil, eliminating the "squeaking" sound caused by cable friction. The bearing is also filled with high-temperature grease to prevent the "squeaking" sound caused by dry friction.

• Upgraded shift fork bushing: The metal bushing where the shift fork contacts the shaft is replaced with a polytetrafluoroethylene bushing, which has a low friction coefficient and is self-lubricating, eliminating the "metal-to-metal" noise during shifting.

III. System Matching: Avoiding Secondary Noise Caused by Parts Compatibility Issues

No matter how quiet a single component may be, noise can still occur if the system is not properly matched. Pay attention to the following details:

• Brake Pad and Disc Hardness Difference: The hardness of both should be "soft" and "hard" (the pad hardness is slightly lower than the disc hardness). The difference should be controlled within Shore hardness 10-15. Otherwise, the hardness mismatch can easily cause "high-frequency resonance."

• Clutch Plate and Pressure Plate Pressure Uniformity: When replacing the clutch plate, the pressure plate diaphragm spring should be checked simultaneously. Uneven spring elasticity can cause uneven contact wear on the clutch plate, resulting in "periodic friction noise." It is recommended to use a genuine factory-matched pressure plate assembly.

• Brake Clearance Adjustment: The clearance between the brake drum and brake shoe should be maintained at 0.2-0.3mm. Too much clearance can easily cause "shaking noise" when releasing the brake, while too little clearance can cause "braking noise." It is recommended that a professional technician perform precise adjustment using a feeler gauge.

IV. Scenario Adaptation: Quiet Configuration Options for Different Vehicle Types

• Family Sedans (focused on comfort): Ceramic composite brake pads + ventilated discs + resin-based silent clutch plates fully meet urban road noise requirements at a reasonable cost.

• SUVs/Off-Road Vehicles (balancing quietness and durability): Low-metal silent brake pads (30% metal) + high-carbon ventilated discs + clutch plates with shock-absorbing springs, enabling handling in complex road conditions while controlling noise.

• New Energy Vehicles (pursuing ultimate quietness): Organic silent brake pads + full-ceramic-coated brake discs + a hydraulic release clutch system, leveraging the inherent low noise characteristics of electric vehicles to achieve "virtually silent braking."

The key to quieting automotive brake and clutch systems is "using soft materials to cushion impact, structural design to eliminate resonance, and system matching to avoid compatibility noise." Selecting ceramic/organic brake pads and clutch plates, paired with ventilated discs and a hydraulic release mechanism, and then precisely tuning and ensuring component compatibility, can significantly reduce noise, restoring a quiet and comfortable ride.If you are looking for brake pads, brake discs and other high-performance brake parts, welcome to our website:https://www.evfriction.com. We provide precision parts and trustworthy services.Or you can contact us by jessicabrakes12@gmail.com.