How To Reduce Sound In Your Car By Sound Deadening Your Wheel Wells

Added 11/13/2022

Supplies needed

   . ResoNix CLD Squares

   . ResoNix Fiber Mat 25 and/or ResoNix Fiber Mat 45 (depends on how much space you have and what you can fit)

   . Optional and preferred: ResoNix Barrier

        Note: ResoNix Fiber Mat is perfectly fine in this location and exposed to the elements. It will not hold water, it will not degrade, it will not grow mold or mildew. This is the very same material that is used in these locations by car manufacturers such as Mercedes.

       Wheel wells are one of the most offensive sources of noise in a vehicle. 

1. Sources of Road Noise in Wheel Wells

Tire Noise: This is generated by the interaction of tires with the road surface. Different textures and materials on the road can cause varying levels of noise. For example, rough asphalt or gravel produces more noise compared to smooth tarmac. The noise is primarily due to the vibrations and air being compressed and released by the tire treads as they make contact with these surfaces.

Impact Noise: When a vehicle travels over bumps, potholes, or debris, the impact is transmitted through the tires and into the wheel wells. This impact creates noise, which can be directly transmitted into the cabin if not adequately insulated.

Spray and Debris: In wet conditions or on loose surfaces like gravel, particles can be thrown against the wheel wells. The sound of these materials hitting the metal or plastic of the wheel wells can be quite loud, adding to the overall noise level inside the vehicle.

2. Pathways of Noise Transmission

Structural Transmission: Noise from the wheel wells can be transmitted to the vehicle’s cabin through the vehicle’s structure itself. The metal and other materials used in car construction can conduct sound waves from the wheel wells into the cabin.

Airborne Transmission: This type of noise spreads through the air gaps and enters the cabin through openings or less insulated parts of the vehicle’s body. Even small gaps can significantly affect how much road noise enters the cabin.

3. Methods of Soundproofing Wheel Wells

Damping Materials: Applying damping materials like mats or pads made from dense material, such as our ResoNix CLD Squares, reduces the airborne transmission of noise through the wheel liners caused by road noise. While ResoNix CLD Squares are typically used to reduce resonance by constraining the panel, they can, in this VERY specific case, work as a mass loaded noise barrier since the wheel liners will not really be able to transmit mechanical energy into the cabin. It works by adding mass to the wheel wells, thereby reducing the ability of the structure to vibrate and transmit noise. Again, this is not the main point of CLD sound deadening materials, but it will behave this way in this specific instance.

Absorptive Materials: ResoNix Fiber Mat can be used to line the wheel wells. This material absorbs sound waves, preventing them from reflecting off the hard surfaces of the wheel well and entering the cabin. 

Barrier Materials: Heavy, dense materials, such as ResoNix Barrier, can act as a sound barrier, blocking the direct pathway of noise into the vehicle cabin. These are usually installed as part of a composite system that includes both absorptive and damping materials. As mentioned before, the ResoNix CLD Squares pretty much take on this role, but adding ResoNix Barrier allows even further noise blocking. This is only for advanced installations though as it will be difficult to install.

4. Impact of Soundproofing on Driving Experience

       By mitigating the noise originating from the wheel wells, the overall noise level inside the cabin is significantly reduced, leading to a quieter and more enjoyable driving experience. This reduction in noise can decrease driver fatigue, increase the effectiveness of in-car communication and multimedia systems, and generally make the vehicle feel more refined and comfortable.

       In essence, soundproofing the wheel wells addresses one of the primary entry points for external noise into a vehicle, making it a key area to target for those looking to enhance their driving experience through noise reduction.

       Below is what I did in my own vehicle, a 2019 Volvo S60 R Design. Please note, that the exact approach will be different on every vehicle. This can be due to how much room there is to work with, moving parts, or more. Please use your best judgment.

Removing Your Vehicles Fender Liners

       First up is obviously removing the wheels and wheel liners. During this process you are going to want to evaluate what you can fit, what parts of the body of the vehicle are going to need the most attention, etc. Remember, resonant panels will need it most. Its crude, but a simple knock with your knuckle will let you know what parts of the body need treatment. More on this part below, but on this particular vehicle, the body was relatively non-resonant, and the wiper fluid reservoir blocked a lot of access on the drivers side. Due to this being planned as a few hour-long project and was recovering from a medical procedure, I did not decide to remove the reservoir and instead worked around it. While getting a closer look, I also noticed that I had gained access to the back side of the fender and the airspace behind it. I decided to also apply ResoNix CLD Squares to the back of the fender and apply ResoNix Fiber Mat 45 on top to fill the airspace.