MICHELIN 2014 endurance racing slicks get green light at Le Castellet

Michelin took advantage of the FIA World Endurance Championship's two-day pre-season 'Prologue' test at Le Castellet, France, on March 28-29, to put its new range of endurance racing tyres through their paces. A detailed analysis of their performance was conducted by MICHELIN Motorsport's engineers and the department's Technical Director, Nicolas GOUBERT: “We are introducing no fewer 12 new tyres this year and it is no exaggeration to say that we have revolutionised our range. It was consequently vital to be able to evaluate them in conditions similar to those we are likely to encounter at the WEC rounds [FIA World Endurance Championship] at Silverstone and Spa.”

The OBJECTIVES AT THE FIA WEC TEST at Le Castellet were to:

  • confirm that the performance delivered by the new tyres not only lived up to the expectations of MICHELIN’s partners, but also corresponded with the French firm’s objectives and data previously gathered;
  • harmonise the way the tyres and cars function together in race trim;
  • narrow down the windows during which the different tyres can be used, notably in preparation for the forthcoming WEC races at Silverstone and Spa.

Dry conditions enabled Michelin and its partners to work notably on the French firm’s range of slicks. The weather for Friday’s sessions provided a wide spectrum of track temperatures, ranging from more than 30°C during the day to 10°C after sunset, and this helped to analyse different windows. Saturday was more overcast and the track temperature remained relatively stable (between 15°C and 22°C), which meant that the engineers were able to simulate the sort of conditions that can be expected at Silverstone and Spa.

Thanks to the fact that 21 of the 27 cars Michelin will equip for the 2014 FIA WEC were in action at Le Castellet, the engineers were able to work with a broad cross-section of cars, although its only LM P2 partner at the test was SMP Racing.

Performance and longevity for Michelin’s LM P1 tyres

The two days in the south of France were very important for Michelin in the LM P1 class, since its objective is to achieve the same level of performance and longevity as last season, despite the fact that its tyres are between 5 and 6 centimetres narrower and 8 kilos lighter (per set of four) than they were in 2013. Indeed, the size of MICHELIN‟s latest LMP1 endurance racing tyres is now the same front and rear, i.e. 31/71-18, instead of 36/71-18 (front) and 37/71-18 (rear) previously.

SOFT HIGH TEMPS. YES Temperature: >10°C / Two stints: okay* / Performance: okay
SOFT LOW TEMPS. YES Temperature: <15°C / Two stints: okay* / Performance: okay
MEDIUM NO Not applicable
RAIN (WET and FULL WET) NO Not applicable
HYBRID NO Not applicable

* Le Castellet is a circuit that is particularly hard on tyres 

LM P2: a ‘no compromise’ switch to ‘non confidential’ tyres

Thanks to the particularly active presence of its partner SMP Racing at Le Castellet, Michelin was able to run its new range of tyres for endurance racing’s LM P2 prototypes. Indeed, from this year, the regulations which cover the class do not permit the use of so-called ‘confidential’ tyres, i.e. those which remain the property of their maker and which contain certain technical secrets. As a consequence, Michelin has designed new tyres which pack its best technology without incorporating elements covered by trade secrets. The aim during their development was to make the change to non-confidential tyres with no drop-off in terms of performance. Like last year, the sizes of the tyres used by the LMP2 prototypes in 2014 are 30/65-18 (front) and 31/71-18 (rear).

SOFT YES Temperature: <15°C / Performance: okay
MEDIUM YES Temperature: >10°C / Two stints; okay* / Performance: OK
MEDIUM Plus YES Temperature: >20°C / Two stints: okay* / Performance: OK
RAIN (WET and FULL WET) NO Not applicable

* Le Castellet is a circuit that is particularly hard on tyres

Consistency a feature of Michelin’s LM GTE slicks

In LM GTE Pro and LM GTE AM, Michelin’s partners will run new WET and FULL WET rain tyres in 2014. However, the weather conditions at Le Castellet did not enable them to be tested. The sizes used by the LM GTE runners are 30/68-18 (front) and 31/71-18 (rear).

MEDIUM HIGH TEMPS. YES Temperature: >10°C / Consistency okay for more than one stint*
MEDIUM LOW TEMPS. YES Temperature: <15°C / Consistency okay for more than one stint*
RAIN (WET and FULL WET) NO Not applicable

* Le Castellet is a circuit that is particularly hard on tyres

“We are very pleased with our two days at Le Castellet, even though we weren’t able to run our wet weather tyres,” notes Nicolas GOUBERT. “The test showed that we are perfectly in tune with the development objectives we set ourselves, and our tyres function efficiently with the cars of our partners in all four classes. In LM P1, we were able to adapt our tyres to our partners’ prototypes without losing the technical DNA of the different versions. Meanwhile, we will continue to analyse our LM P2 tyres at the pre-European Le Mans Series ‘Prologue’ which will take place at Le Castellet in the coming days.

“We will spend this evening with our partners in order to obtain their views ahead of Silverstone and Spa. After that, we will begin the production of our tyres for Silverstone and work on the logistical arrangements necessary to transport them to the United Kingdom.”