One for snow, one for icePirelli has completed the presentation of its range of tyres for this year's FIA World Rally Championship with two winter tyres: the Pirelli Sottozero "Snow" and Pirelli Sottozero "Ice".
These are two quite different tyres, each of which
has been specifically designed to offer the best possible performance during very specialized rallies such as Monte Carlo and Sweden. The tyre for the first event of the season is available in two versions, with or without studs, depending on the rally's road conditions.
Sottozero "Snow"
This tyre has dimensions similar to those of the Pirelli PZero asphalt tyre and incorporates studs that protrude by 1 to 1.5 mm. Nonetheless, it is capable of covering long road sections without damaging the road surfaces.
It has been specifically designed for mixed conditions and in particular the Monte Carlo Rally stages, which are often held on roads that are partly dry but also partially snowy and icy. The structure of the new Sottozero Snow is more flexible compared to that of the asphalt PZero and this is mainly down to the fact that this tyre has to deal with particularly variable road conditions. The shoulder of this tyre has also been specially reinforced in order to better resist punctures, as the anti-deflation mousse used up until the end of 2007 is no longer allowed.
The compound and tread patterns have been designed to operate in the best possible way both with studs attached - for heavy snow conditions - and also without studs, in order to provide a good level of grip even on slippery surfaces with very low temperatures.
The teams will only be allowed to use one type of tread pattern, construction and compound. This compound will be very similar to the compound used on Pirelli's winter road car tyres. However the drivers are able to choose whether or not to add studs to their tyres, depending on the road conditions.
Sottozero "Ice"
The Pirelli Sottozero Ice tyres for rallies such as Sweden are designed for roads entirely covered in ice.
They use a narrow tread pattern, which provides a bigger pressure on the road surface and consequently more grip.
This Pirelli tyre, intended for the usual snow and ice conditions of Sweden, incorporates compact plugs in order to best retain the studs which are fundamental in providing good grip on the icy and snowy roads of Scandinavia. In order to provide the most traction possible on snow, Pirelli's engineers have designed an extremely narrow and deeply sculpted tread pattern.
The tyre is of an asymmetric design and the studs are added during the production process, using technology specially patented by Pirelli, rather than afterwards. Once again, just one type of tread pattern, construction, compound and stud is allowed by the FIA - world motorsport's governing body.
The construction is reinforced in the sidewalls in order to resist lacerations and punctures now that anti-deflation mousse has been outlawed.
From next year, a new size of Pirelli Sottozero Ice tyre will be made available, measuring 7" x 15". This has been introduced in order reduce the number of different rim sizes used on the FIA World Rally Championship. Consequently, teams will have to use the same rims on snow rallies in 2009 as they do on conventional gravel rallies.
Press Release Pirelli
