1978 LE MANS 24 HOURS: Renault triumphs at Le Mans with Michelin radial technology
It was this week forty years ago, on June 11, 1978, that Michelin and Renault-Alpine’s Pironi/Jaussaud put radial technology on the top step of the podium at...
Michelin’s unbeaten spell at Le Mans that has lasted since 1998 can be explained by the performance and consistency of the successive generations of endurance racing tyres it has developed. They have long been capable of covering multiple ‘stints’ all the way to the finish line with no loss of efficiency, and these are the very same qualities that the French firm’s partners know they can expect for the 2018 Le Mans 24 Hours.
In recent years, the regulations did not permit tyres to be changed while cars were being refuelled, and only one wheel-nut gun was authorised to remove and fit wheels. As a result, fitting fresh rubber took up valuable time in the pits, and this encouraged teams to keep the same set for several stints.
This phenomenon played perfectly to the strengths of Michelin’s tyres which are able to cover distances in excess of 700km at average speeds of around 220kph, with no fall-off in either performance or safety.
For this year, however, the picture has changed, since the regulations now permit tyres to be swapped as fuel is being pumped into the cars, while two wheel-nut guns and two mechanics are allowed to work in the pit lane. “It now takes around 15 seconds longer to refuel than it does to fit new tyres. As a result, changing rubber no longer represents a penalty in terms of time, so teams are tempted to switch more frequently,” notes Jérôme Mondain, the manager of Michelin Motorsport’s endurance racing programmes.
All the same, teams will be compelled to run multi-stint strategies since a maximum cap concerning the number tyres they can use is in place. The LMP1 prototypes, for example, have a quota of 12 sets of slicks for Le Mans, which means they will have to run triple or even quadruple stints of around 40 minutes each. In LM GTE, the cars will have to double stint, at least.
“In spite of this evolution, there continues to be every justification to highlight the durability of our tyres,” says Jérôme Mondain. “This new regulation will clearly have a knock-on effect with regard to the teams’ strategies and will no doubt increase the number of tyres that are actually used, whereas the likes of Porsche and Audi used only nine or ten sets to win the race in recent years.”