MILAN, ItalyPirelli Tyre S.p.A. and Continental A.G. have developed tires for Audi Group that are designed to reduce noise for occupants of the car by using a layer of polymer sponge that is adhered to the inner liner of the tire.
Pirelli claims the innovationbeing pitched as Pirelli Noise Cancelling Systemcan reduce the noise heard by those inside the car by 2 to 3 decibels, or roughly half. Conti claims its technologydubbed ContiSilentcan reduce the tire-generated noise level reaching a car's cabin by as much as 9 decibels.
With this development, the tire makers are addressing noise caused by the vibration produced when air inside the tire is compressed as the tire is squashed against the road. This noise is transmitted from the tire to the wheel hub and eventually reaches the inside of the car's cabin via the steering and suspension components.
Pirelli said the vehicle industry's trend toward lighter-weight cars has brought about the need for this technology. The polyurethane foam sponge is designed to absorb these vibrations, the tire maker said, and thus reduce the amount of noise passed through to the cabin.
Audi is offering tires built with the noise-cancelling system as optional OE fitments on its RS6 Avant and RS7 Sportback models, running on 285/30ZR21- and 275/30ZR21-sized tires, respectively.
Conti has added the foam inserts to its ContiSportContact range; Pirelli did identify which tire models are being supplied.
Adding the PU sponge adds about 10.5 ounces of weight to the tire, an amount Pirelli said has no effect on the tire's other performance characteristics. The material is added to the tire after the tire is cured.
Pirelli did not say whether the development affects noise as observed by those outside a vehicle, nor did it comment on what the added cost is.
The company said introducing this technology answers growing demand in the automotive world for reduced noise levels both on the inside and outside of the car as well as address the latest European regulations to reduce noise pollution.
This story first appeared on www.tirebusiness.com.