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Michelin GTLM Insider: The Magic of “Single Stint” Tires

A look back at the introduction of Michelin’s Single Stint tire…

Photo: Michelin

Photo: Michelin

Fans weren’t the only ones watching when Michelin rolled out a new “single stint” tire at Road America last year.

The Ford Chip Ganassi Racing team had tested the new Ford GT with Michelin earlier in the week before returning its focus to its Daytona Prototype for the race.

“We were watching GTLM qualifying and one of the Porsches did two hot laps, broke the GTLM track record by 1.4 seconds and immediately pitted,” recounted Ford Chip Ganassi Racing managing director, Mike Hull, on the Sunday pre-grid.

“We looked at each other and said, ‘Wow! What was that?’”

What it Was

“That” was a first generation Michelin “single stint” tire designed for use in the 2015 GTLM class at Road America and VIR.

Photo: Michelin

Photo: Michelin

Why it Was Created

“There were a couple of factors that motivated us to create that generation of tires,” said Ken Payne, technical director motorsports, Michelin North America.

“Until that point, we were generally racing our WEC series Michelin GT tires here in the IMSA GTLM class.

“The Michelin WEC tires are designed for double- or triple-stints at Le Mans. They are fast and deliver incredible consistency, but it takes them slightly longer to build pressure and temperatures.

“Unlike Le Mans and the WEC series, the IMSA pit rules allow tire changes and work on the car during refueling.

‘As a result, there was rarely any advantage to multi-stinting tires. Teams were changing tires on nearly every pit stop.

“The other factor was that we had a competitor supporting a single GTLM car and with just one car it would not be a big stretch for them to create a short duration tire for a late race stop to try to gain an edge.”

Photo: Michelin

Photo: Michelin

Why Road America?

“We were curious as to what would happen if we created a more aggressive tire to use for a single stint,” said Payne.

“Road America and VIR are both very fast tracks, and fairly similar from a tire standpoint as we classify them as moderate energy circuits. We decided to create a new tire to try at those two races.”

Taking advantage of the rare opportunity to be freed of the multi-stint design constraint, Michelin engineers and tire developers explored more aggressive constructions and compounds to optimize single stint performance.

Photo: Michelin

Photo: Michelin


When rains limited Friday practice, it was Saturday morning before Porsche’s Earl Bamber got his first dry laps of the four-mile long Road America circuit.

Bamber, who had never previously seen Road America, got in just four full laps of practice.

Then came qualifying. The GTLM track lap record was 2:03.747, set the previous year by BMW Team RLL’s John Edwards.

On his second flying lap, Bamber clocked a 2:02.384 to shatter the record by nearly 1.4 seconds, then immediately pitted.

He was not alone. Corvette Racing’s Antonio Garcia and Risi Competizione Ferrari’s Giancarlo Fisichella also bested the BMW’s Road America GTLM lap record by 1.1 seconds with the new tires.

Photo: Michelin

Photo: Michelin

Race Days

The Road America race produced a similar story as Porsche’s Patrick Pilet and Nick Tandy started at the back of the field after an engine change; then drove through the GT field to claim the victory.

Along the way, Tandy destroyed the race lap record set the previous year by Marc Goossens in the Dodge Viper SRT by a stunning 2.478 seconds with a time of 2:02.789, a second faster than the previous qualifying record.

VIR produced similar results as Tandy broke the VIR GTLM class qualifying record by 1.254 seconds.

Tandy and Pilet again combined for the win at VIR, and Risi Competizione Ferrari’s Pierre Kaffer smashed his own 2014 race lap record by 1.288 seconds.

“The biggest difference in the Michelin tires is the pace,” said Tandy afterwards. “You don’t feel any difference.”

Photo: Michelin

Photo: Michelin

The Importance of Tires

“Our friend Allan McNish often referred to our lead Michelin tire developer with Audi as ‘Magic Jerome,’” said Payne.

“Allan said that Audi could arrive at a test with a number of new bits and gain two or perhaps three tenths of second per lap.

“Jerome would have new tires for them to try and they may improve a full second per lap, hence the nickname.

“Every tire is a different challenge. Creating a tire that can perform at a very high level for multiple stints is a big challenge, and creating a super-fast tire for a single stint is a different challenge.”


Despite the success of the “single stint” tires, they won’t be part of the Michelin portfolio at Road America or VIR in 2016.

“We started the 2016 IMSA WeatherTech SportsCar Championship season with a second-generation of our “single stint” tires before switching to the 2016 WEC tires at Monterey,” said Payne.

With GTLM as the only open tire class in the WeatherTech Championship and Michelin the tire chosen by all the GTLM teams, IMSA officials asked Michelin to hold off on the introduction of any new tires after the 2016 WEC tires became available.

“We understand IMSA’s desire to manage its Balance of Performance,” said Payne, who does not expect new records this year.

“Last year our GTLM teams cut into the stratification of classes that IMSA desires.”

Photo: IMSA

Photo: IMSA

Identifying Fresh Challenges in IMSA

Pascal Couasnon, Michelin global director of competition, said again last week, that Michelin is in racing to meet challenges and that there must be a challenge for them to be interested.

“We are working with IMSA to identify ways to challenge ourselves within the current framework,” said Payne.

“Obviously open tire competition provides a challenge. If there is no tire competition, then we need something to push for, like meeting a new level for rolling resistance in Formula E, or the challenge to reduce the number of tires in WEC, where we also have open competition.

“Michelin is in motorsports to develop technologies and innovations that we can apply to our product lines.

“If we sit back and go into ‘cruise’ mode, then we will not be pushing as hard to develop innovative technologies and insights to benefit our future tire lines and we will be at a disadvantage when we do face competition.

“We learned a lot here last year by exploring some new territory. We gained some valuable insights and finding one or two seconds a lap is not something that our engineers suddenly forget.”

And neither will the teams and fans who witnessed ‘that’.

The latest news, photos and video features from the trusted Sportscar365 web staff.


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