How Brake Shims Control NVH in Modern Automotive Braking Systems

How Brake Shims Reduce Noise and Vibration in Modern Vehicles?

Noise, vibration, and harshness continue to be major problems in the design of vehicles nowadays. With the powertrain getting more efficient and the whole process of electrification, vehicles are generally quieter. This makes the drivers pay more attention to the noise coming from the brakes. In this case, brake shims can be considered as the main component that helps to tackle this problem.

Comprising only a few inches in size, brake shims greatly impact not only the comfort and durability of the braking system but also the overall experience of driving. Knowing the working principle of brake shims, one can understand their rising significance in the automotive systems of the present time.

Understanding NVH in Automotive Braking Systems

NVH stands for the noise, vibration, and harshness that cause hearing discomfort and physical discomfort to the vehicle occupants. If NVH issues occur in the braking system, it is usually in the form of nags, squeals, judder, and vibrations during the application of brakes. Such problems are mainly attributed to the contact of the brake pads against the rotors and the combination of this friction with mechanical resonance. Even very slight differences in the mode of applying pressure or in the interaction of the materials can result in noise being emitted.

Since vehicle cabins are becoming more sealed off from the outside and engines are generating less sound, the drivers can now easily detect the noise of the brakes. As a result, the demand for quiet and smooth braking is at a high level. Therefore, vehicle manufacturers are concentrating on each individual brake part that can have an impact on the NVH behavior of the vehicle. Brake shims, since they are in direct contact with the vibration sources at the brake pad interface, have played a major role in this solution.

The Role of Brake Shims in Controlling Vibration

Brake shims are thin strips that go between the brake pad and the caliper piston. Their main purpose is to soak up the vibrations caused by braking. When brake pads hit the rotor, friction causes fluctuations. If there is no damping, these vibrations can be carried into the caliper and the suspension parts.

Brake shims function by breaking the vibration route. They take in the energy before it gets turned into a sound that humans can hear. A lot of shims consist of multi-layered structures that mix the metal, rubber, or polymer coatings. These layers change vibration energy into a small amount of heat, which lowers the resonance. Brake shims, which hold the brake pad firm against the caliper, also contribute to the even distribution of pressure. This in turn lessens uneven pad wear and leads to better braking reliability. Consequently, braking systems give a sensation of being smoother and quieter after some time.

Material Advancements Improving Brake Shim Performance

Material innovation has been the main factor in brake shim effectiveness improvement. Simple metal plates were early brake shims, and they could only control vibration to a very limited extent. Present-day shims feature multi-layer structures tailored to specific performance requirements.

Rubber-coated shims are very common to provide basic damping as well as corrosion resistance. Multi-layer steel shims offer stiffness and vibration damping at the same time. Polymer coatings of the latest generation bestow even more thermal stability and noise attenuation. There are some manufacturers who use adhesive-backed shims that not only guarantee proper alignment but also decrease movement during braking. Thus, these products can prolong the life of brake pads, and NVH characteristics can be retained even after multiple braking cycles. The type of vehicle, the braking load, and the operating conditions determine the material chosen. Passenger cars mainly focus on comfort and noise reduction. Performance and commercial vehicles need shims able to resist higher heat and stress levels as well as control vibrations.

Growing Importance of Brake Shims in Modern Vehicles

Owing to the changes in vehicle technology, brake shims are gradually gaining importance. Electric and hybrid vehicles produce less sound from the engine, so the noise of the brakes becomes more obvious. Besides, regenerative braking changes the way the brakes work, which makes one more sensitive to NVH problems.

In fact, if damping components are not well optimized, lightweight vehicle designs can increase the level of vibration. Brake shims therefore serve to neutralize these effects through better acoustic control of the braking interface. In October 2024, Akebono Brake Industry added to its range of low-noise brake pads by significantly integrating shims that are mainly targeted at electric and hybrid vehicles. The company showed how enhanced shim structures facilitate quieter brake workings and meet the requirements of the changed vehicle architectures. Such a product focus is indicative of the increasing use of brake shims in solving the new NVH problems.

Impact on Vehicle Comfort and Long-Term Performance

Efficient brake shims do much more than just reduce noise. They also help make the entire brake operation smoother and keep the parts lasting longer. When there is less vibration, the brake pads, calipers, and mounting hardware experience less stress. As a result, the wear and tear of these parts occurs at a slower pace.

It is also a fact that drivers find the brake pads more comfortable and get a more stable reaction whenever they press the brake. On the one hand, in case of manufacturers, the improved NVH (Noise, Vibration, and Harshness) performance gives them a greater level of customer satisfaction and fewer warranty claims. Thus, brake shims become an affordable way to raise the quality of the vehicle.

Due to regulations and consumers constantly raising their expectations, manufacturers are prioritizing vehicle braking performance more than ever before. Thus, brake shims have become essential components of the brake systems and are no longer viewed as mere accessories or add-ons. They are now a key part of the design and optimization of braking systems.

Explore the full industry analysis and future outlook in our detailed report on the Automotive Brake Shims Market.

Why Brake Shims Will Remain Essential Going Forward?

Brake shims will remain at the core of controlling NVH as cars get quieter and more sophisticated. Their vibration damping capability, thus enhancing comfort and at the same time aiding durability, makes them indispensable for contemporary braking systems. As innovations in materials and vehicle designs continue, brake shims will still be the main target of manufacturers aiming to provide smooth and dependable driving experiences.