No rest for the tyres !

Michelin is preparing itself for a new encounter and a new challenge on the legendary Silverstone circuit at the fifth Le Mans Series race out of six scheduled for this year.

Silverstone - built on a former military airfield - makes a welcome return to the Le Mans Series this season after being replaced by Donington Park on the 2006 calendar.

The French tyre manufacturer aims once more to offer the very best products and services to all of its partners in order to give them the best possible chance of a podium finish. Nonetheless, the British circuit is well-known for its high-speed demands - which could lead to some tyre compromises between the left and the right side of the car.

Michelin will offer four different tyre solutions to its partners running prototype cars, including a new evolution of 'medium' tyre that has performed strongly in tests.

The circuit:
Track length: 5.141 km

Matthieu Bonardel, Circuit and Rally Competition Manager

"This year sees the return of Silverstone to the Le Mans Series instead of Donington, which took its place on the 2006 calendar. People often believe that a visit to Silverstone automatically entails a wet race. The last time the LMS came here two years ago, however, this was actually the only round of the season that wasn't affected by rain! The weather can in fact be quite warm and, when it is, Silverstone calls for optimal grip at high speed, making it a bit like Monza - without the chicanes.

Silverstone is also a circuit that offers a bit of everything. The corners are all very different to each other, incorporating low, medium and high-speed bends in quick succession. It's really the only circuit of its kind all year: other tracks tend to have whole sections that are either slow or fast.

The fast corners tend to flow into each other without any real straights in between, so despite the high average speeds, we generally don't have a problem with the front tyres: it's the rears that always suffer the most. It's not uncommon to run harder compounds on the left-hand side of the car, in order to cope with the mainly right-hand corners. And naturally we also need to have a good stock of wet tyres-- just in case!"

The tyres

Matthieu Bonardel, Circuit and Rally Competitions Manager

"Silverstone is not a circuit where we find the highest average speeds, or even the highest straight-line speeds, but instead it distinguishes itself by a succession of quite challenging corners. Consequently there's no rest for the tyres. They are constantly worked hard, with the exit of one corner leading to the start of the next - taking in a variety of speeds and without the break of a straight in between. Most of the corners are to the right, loading up the left-hand side of the tyre. Finally, there is a lot of grip in the dry, on quite an aggressive surface.

If you put these two things together - the extra work for the left tyres generally and the demanding surfaces - it's clear that the left-hand side of every tyre is under a lot of stress. This can provoke some degree of wear on both the front and rear tyres during the race, depending on the set-up of each individual car. The teams tend to choose harder tyres than they would for other circuits, and when they use soft tyres it's only on the right-hand side of the car. All the information we have leads us to suggest a compromise with left and right hand tyres at Silverstone more than anywhere else. I think this could be a rewarding strategy.

We will bring four dry-weather solutions for the prototype cars, including a medium 'joker' tyre that has proved to be both fast and long-lasting during our most recent tests. For the GT cars, we will have a medium and a hard option. Our objective is clearly to double-stint with the tyres. When it rains, Silverstone becomes extremely slippery with very little grip and a considerable risk of aquaplaning. At Spa, it was possible to use dry tyres even in the wet, but at Silverstone we would advise the use of classic rain tyres in the wet with grooves.

It's a very interesting circuit, as we will revisit a variety of different conditions that we have already encountered earlier in the year. For some teams, Silverstone could be the final race of the season - if they don't go to Brazil, which is the last race on the calendar. "

The Michelin Energy Endurance Challenge

Michelin has created the Michelin Energy Endurance Challenge for the 2007 season to reward the teams with the most efficient energy use during each of the six rounds of the Le Mans Series and the Le Mans 24 Hours.

This challenge is based on a specially calculated formula that goes under the name of the Performance Energy Index (IP). The formula is based on the weight, fuel consumption and the average speed of each team's cars during the race.

-credit: michelin