The Audi R10 TDI is the most successful car in the 2008 American Le Mans Series with three overall victories. The Audi drivers are particularly looking forward to the next race on 9 August: Road America in Wisconsin is not only regarded as one of the world’s most picturesque and challenging circuits. The track is also the fastest on the American Le Mans Series calendar.
 
Just like its predecessor, the R8, the Audi R10 TDI was specifically developed for the 24 Hours of Le Mans: The average speed around the high-speed circuit approaches 250 kph. Road America comes closest in this respect to Le Mans: Last year, Allan McNish took pole position at an average speed of 217.829 kph in the Audi R10 TDI. It is still the fastest lap for a Le Mans sportscar in the history of the American Le Mans Series.
 
The Audi drivers hunt this record at Road America. The probability is extremely high that it will be beaten – assuming the weather plays its part. Last year, the Audi Sport North America team actually still competed with the first generation diesel sportscar. The two cars to be fielded this time are of the latest technical configuration and are thus significantly quicker.
 
The tyres also play a large role in the LP P1 performance gain and faster lap times. "Our tyre partner Michelin is doing a fantastic job," explains Audi factory driver Marco Werner, who has already celebrated three overall victories in the 2008 American Le Mans Series together with Lucas Luhr. "The tyres have very good grip this years and are very consistent". In the last race at Mid Ohio, Luhr/Werner only had to change tyres once – this was impossible last year.
 
Almost 50,000 test kilometres went into the latest generation Michelin tyres. One-and-a-half hour’s work goes into a single handmade tyre, which weighs approximately twelve kilograms and comprises of 150 different components. Its optimum operating temperature is about 80 degrees Celsius and the tyre itself is of great importance in the overall package of a race car. Compared to last year, the technical experts from Michelin calculated that the tyre alone was accountable for reducing lap-time by one second at the season opener at Sebring. To achieve this you need to increase engine power by about 40 hp or weigh 50 kilograms less.
 
Four different slick versions are available for the Audi Sport North America team: "soft", "medium", "hard" and "hot" – the last one is a version for higher temperatures. Two different rain tyres and intermediates for damp conditions complete the Michelin range.
 
The French company was Audi’s exclusive tyre partner for the R8 project. Michelin was also integrated from the very beginning of the Audi R10 TDI development and broke new ground just like Audi Sport. "We made a lot of pioneering work together," stresses Head of Audi Sport DR Wolfgang Ullrich. "The enormous torque produced by the TDI engine and the relatively high weight of a twelve-cylinder make great demands of the tyres."
 
Every track on the American Le Mans Series calendar is simulated weeks before the event by Audi Sport in Ingolstadt. Michelin give recommendations for air pressure and camber values based on this data.
 
Thanks to the computer simulations, Audi Sport knows before an event almost to the tenth-of-a-second what lap times are possible. "Often", grins Lucas Luhr, "we drive just a little bit quicker than the computer calculated."
 
Whether this will be the case this time will be revealed on Friday (8 August) at
3:30 p.m. local time (10:30 p.m. in Germany) when prototype qualifying is on the agenda. The race starts on Saturday at 4:00 p.m. (11:00 p.m. in Germany) and runs into the night. Swiss driver Marcel Fässler, who contests his first race with the Audi R10 TDI at Road America, is new in the Audi Team.