The 2005 Formula One world championship is entering its most intense phase ďż˝ this Sundayďż˝s Grand Prix of Europe is the second of eight races compressed into only 11 weekends. Hot on the heels of its Monaco GP victory last weekend ďż˝ its fourth consecutive success in the principality ďż˝ Michelin will be chasing an eighth straight F1 victory.

Host venue the Nďż˝rburgring has one of the most famous names in motorsport, although it owes its celebrity to the daunting, 22.835-kilometre (14.189-mile) track that nestles in the forest alongside its contemporary counterpart. The original Nďż˝rburgring opened in the mid-1920s and hosted 22 world championship grands prix between 1950 and 1976. It was dropped from the schedule one season before Michelin began its original F1 adventure.

The present track was extended in 2002 and now measures 5.148 kilometres (3.199 miles). It was first included on the F1 calendar in 1984 and this weekend marks its 13th appearance. It is the 15th time the GP of Europe has counted towards the world championship. The Nďż˝rburgring has previously staged the event on nine occasions and has been its permanent home since 1999. The German and Luxembourg GPs have also taken place here.

Michelin has won the GP of Europe on three occasions: 1983 (Nelson Piquet, Brabham- BMW, Brands Hatch), 1984 (Alain Prost, McLaren TAG Turbo, Nďż˝rburgring) and 2003 (Ralf Schumacher, Williams-BMW, Nďż˝rburgring). In last yearďż˝s corresponding fixture, Takuma Sato (Bďż˝Aďż˝R-Honda/Michelin) made history as the first Japanese driver to start a world championship grand prix from the front row of the grid. His team-mate Jenson Button was the leading Michelin finisher, in third place.

Pierre Dupasquier, Michelin motorsport director
ďż˝It is always slightly tricky to prepare tyres for events at the Nďż˝rburgring, because the weather is unpredictable throughout the year. Even in May, it might vary by up to 20 degrees from one week to the next. In meteorological terms it certainly isnďż˝t as stable as Monaco, where we recorded our seventh straight Formula One success last weekend.ďż˝
ďż˝Our latest grand prix victory puts us in good heart coming into Sundayďż˝s race. The Nďż˝rburgring is a balanced track and, fickle weather apart, doesnďż˝t pose any specific technical problems. There have been no major changes since last season, so we are dealing with a known quantity. We have evaluated some interesting tyre options during recent testing and Iďż˝m sure we will continue to give our partner teams a performance edge, just as we have at every circuit this season.ďż˝

Driver perspective:
Ralf Schumacher, Panasonic Toyota Racing
ďż˝Controlling tyre wear is a massive factor at every track and the Nďż˝rburgring is no different. The circuit is fairly typical in Formula One terms and has become even more so since it was modified a couple of years ago. The surface is usually quite abrasive at the beginning of the weekend, but then tends to calm down.ďż˝
ďż˝Wet tyres will be an important consideration, too, because the weather can be very changeable so we have to be prepared for every contingency. Come what may, I am confident that Michelin will rise to any challenge. On a personal note, I always enjoy this race and its atmosphere because it is the closest F1 circuit to Kerpen, where I grew up.ďż˝

Technical focus
VARIATION IN FRICTION COEFFICIENT ON DAMP OR WET ROAD SURFACES
Friction coefficient is always worse on a damp track and varies enormously according to surface type. The reason? A film of water between the rubber and the asphalt prevents the molecular adhesion mechanism from working. It is vital, therefore, to break this film. On the other hand, the indentation* mechanism, which is vital to grip, will still be operational. In the wet, microrough road surfaces (see Monaco GP racecard) provide optimal grip. If the depth of water increases (wet surface), micro-indenters might become flooded. Macro-indenters continue to perform their drainage and storage roles, but there remains a risk of high-speed aquaplaning. Water interferes with grip and tyres must be designed to disperse it quickly and effectively by adjusting the shape of the contact patch and the tread pattern.
Macroroughness drains and stores water but does not break through the residual film of water.
Microroughness creates individual high-pressure points between the surface and the tyre, to help it break through the film of water

* Roughness effects (indentation)
As soon as a tyre starts to slip over the road surface, the macroroughness and microroughness of the surface cause the rubber to move within a whole range of frequencies. This is also described using the word indentation, which emphasises the penetration of road roughness into the tyre tread.