Tyre Noise: Causes and Prevention
Published On 20-Mar-2020
A frequent, and rather well ignored, source of annoyance in our daily life comes from the soles of our vehicles. The noise that tyres create when driving would fall as one of the primary hassles to anyone who is planning to spend long hours behind the wheel.
But exactly what is this noise created by, and what can we do to stop it?
Firstly, one thing to be understood clearly is that the very reason we have tyres is also the reason we have tyre noise. The radials that adorn our wheels help to keep the vehicle firmly gripped, ensuring the best traction when driving. This, in turn, requires a continuous flow of friction between the tyre and the floor. A by-product of this friction created between the tyre's surface and the road's surface is the squealing noise that we have grown to detest so much.
In other words, this noise that our tyres create is also the reason our vehicles are well asserted on the roads. So, the bottom line here is that if you want your tyres to do their job well, this is a side effect you'd have to put up with. Although it has been possible in recent years to reduce the tyre noise and to enhance the ride quality to a certain amount, completely shedding tyre noise is impossible. And so, it is mandatory for anyone driving with a set of tyres on their wheels to be able to put up with the smallest level of tyre noise in all circumstances.
The reasons for tyre noise:
As mentioned above, the prime reason is that the friction between the rubber and the road surface emits this squealing noise. With a tighter grip, a higher noise level is also expected. Another reason behind this is, when rolling at a high speed, air is pulled in and compressed between the tread grooves. This releases the noise that we've gotten accustomed to when driving. As a result, different types of tread designs will cause different levels of noise, for the groove pattern would differ between them.
Tyres made for off the road conditions will be louder, with the science here being the same as listed above: with a higher grip, comes a higher noise, and off the road tread patterns are made for a far sterner grip and, consequently, they lead to a more insensitive bearing for the passengers.
On the other hand, tyres that are meant for high performance instead of high grip, such as those with asymmetrical patterns, will leave the quietest experience for the driver. An example would be tyres made for Grand touring and sports cars. These are made for lesser resistance when driving, and a lighter hold for the vehicle, so that it can flow forward to higher speeds easily. As a result, the level of grip needed for these tyres is far lesser, and with a smaller friction level built between the tyre and the road, the noise level is also reduced.
Another factor leading to tyre noise is the chamber within the tyre. The void space inside of the tyre acts as a large resonant chamber, amplifying the noises arising within it.
How companies are reducing tyre noise:
Companies today are undertaking tyre noise with an intent resolve, and many of the premier tyre brands manage to engineer radials with the lowest noise emissions. Some tyre companies are designing their tread pattern in ways that makes the air compression noises cancel each other out. Specially designed grooves can reduce noise emissions by scrambling the sound waves arising from the air compression.
An example is Bridgestone, which is already implementing this technology in many of its tyres. This is an innovative technique that many other companies are also beginning to employ today. Furthermore, some are designing tyre grooves in a manner that controls the noises bouncing underneath the car.
Pirelli has architectured an advanced technique to reduce noise emission to the fullest. Known as the PNCS, or the Pirelli Noise Canceling System. The inner lining of the tyre is imbibed with a strip of polyurethane. Made as a spongy, noise absorbing material, this polyurethane consumes the noise bouncing within the large, empty inner air chamber of the tyre. As mentioned above, the spacious, voided inner chamber of the tyre is a primary cause behind the tyre noises experienced. As a result, this is a greatly effective method to gash out the most tyre noise possible.
Most of the tyre brands today help to bring the best ride comfort by asserting noise emissions as an active problem for their tyre designs, and using technology and innovation to bring the noise levels down as far as possible. It is only through the road of innovation and compatibility that would unleash the best potential out of anything that is invented, and tyres are no exception in this regard.