Vehicle tires act as a drum for road noises in that the rubber absorbs bumps in the road, the same way the head of a drum absorbs taps from a drumstick. Expansion joints, potholes, and heaves pound the rubber, which compresses the air inside and transmits hollow thuds to the cabin. The hollowness of the tire functions like the cavity of a drum — allowing the noise to amplify and reverberate.
Polyurethane Foam Noise Canceling Insulation
Tire manufacturers have long been working to decrease road noise. One area where they’ve been successful is the inclusion of noise-reducing polyurethane foam inside the tire liner on the opposite side of the tire’s tread. The polyurethane foam is meant to absorb noise and vibrations from the road closest to their point of origin. The polyurethane foam acts in much the same way as the insulation in a sound studio.
These acoustically insulated tires have stealthily spread through the market to all the major tire manufacturers now offer them.
Just by looking, you wouldn’t know the polyurethane foam is there. The tire looks and functions in the same way as a standard car tire from the outside. It can be mounted and used the same way as any conventional tire, meaning the special polyurethane noise-canceling tires can be installed on any popular make and model of vehicle.
Noise Reducing Technology in Electric Vehicles
The dawn of the electric vehicle is upon us, and with it comes some unforeseen challenges for car manufacturers. For example, compared to a combustion engine, the silence of an electric motor makes road noises more pronounced. Tire manufacturers have turned their concentration to road noise reduction in this growing car market segment. Some tire manufacturers have constructed tires specifically for electric vehicles. The interest and effort to make tires a crucial element of a quieter ride will only grow in the coming years. The number of electric vehicles on American roads is projected to reach 18.7 million by 2030. That’s up from just one million vehicles back in 2018. All major tire manufacturers now make acoustic polyurethane-insulated tires. The offering is even standard on some high-end vehicles.
Average Sound Level
Insulated tires Standard tires
Concrete with expansion joints, 70 mph 69 dBA 70 dBA
Concrete with expansion joints, 45 mph 64 dBA 64 dBA
Smooth asphalt, 70 mph 64 dBA 64 dBA
Smooth asphalt, 45 mph 58 dBA 57 dBA