This year, Michelin took over from Continental as the sole tire supplier for the IMSA WeatherTech SportsCar Championship and the supporting Michelin Pilot Challenge (formerly Continental Tire Sports Car Challenge) and IMSA Prototype Challenge series. It’s been a season of shattered lap records and good press.
In a single off-season Michelin went from supplying nine cars in the GTLM class to over 100 across the paddock; from using 2,000 tires at Daytona to almost 13,000. It’s a huge commitment, and one that has required the French constructor to develop and supply selections for DPi, LMP2, LMP3 GT3, GT4 and TCR cars in addition to its GTLM rubber.
Beyond Michelin’s effort in the WeatherTech Championship, the company’s racing division has been pushing hard to ensure a similar level of quality for it services in the Pilot Challenge Series, which is packed with aspirant teams and drivers.
Since the selection of Pilot Challenge, GS class teams were able to sample the 2019 Michelin tires last year at Road Atlanta in a test held after Petit Le Mans, and it’s been full-steam ahead ever since. In Pilot Challenge’s GS class, Michelin has put faith in its two selections for the season, the S8M and S9M, with the aim of providing performance and consistency across in a variety of conditions for the 11 different GT4 chassis that compete in the series.
“Producing tires for Pilot Challenge creates a different challenge than what we have in a ACO GTE Pro or, GTLM,” said Chris Baker, Michelin’s director of motorsport in North America, in conversation with RACER. “And it’s certainly different than the challenges we face in Prototype.
“You do have, just like in GTLM, mid-engined, cars, you have rear-engined cars, and you have front-engined cars. In Pilot Challenge’s GS class we face the same scenario. But these are not factory efforts. So we are not doing in-depth simulation, sharing in-depth tire models and that sort of thing. There’s a lot more track testing, anda lot more empirical data involved in creating these tires.
“And keep in mind, we went into this debut season with a family of tires that was created around two years ago, using at that time the best information that we had from experience in Europe and in Asia, but not here in North America.”
For a team like Motorsports In Action, which was in the title hunt for GS with its McLaren 570S GT4 until last weekend’s last-lap drama at VIR, the move to Michelin has proved to be a fruitful one. Team owner Eric Kerub feels that there has been a noticeable step up in the quality of the tires now available, even in this early stage of the program.
“When we went and tested them for the first time, we were eager to see the difference,” he said. “Our car, with the extra weight, the way it’s built, means the tires fall off earlier in the race. We had hoped that the Michelins would last longer and allow us to double-stint and give us more of an edge, and they do.”
In Pilot Challenge, the GS class teams used the S8 tires through the opening races of the year before switching to the harder-S9s for the summer races which feature higher temperatures, and then move back to the 8s for the end of the season. This adds a layer of variables that IMSA has had to factor in when balancing the field.
“We’ve had discussions with IMSA on how they address the dynamic changes with the tires in terms of BoP,” Kerub said. “It’s something they are going to need to get a handle on, as the two compounds affect different cars at different circuits.
“But we’re happy all around. The Michelins are much more manageable tires in terms of performance expectation. You now know what you’re going to get from them at the beginning, middle and at the end of a stint. Before it was inconsistent and harder for IMSA to BoP. This change of tire brand is part of the reason why you’re seeing the series being more balanced and equal.”
MIA driver Jesse Lazare explained that the team’s 570S GT4 reacts very differently to each circuit than it did on the previous tires. The new rubber has provided him and his teammate Corey Fergus with renewed confidence behind the wheel.
“I feel a lot more confident in smashing curbs now, you don’t have to baby the tires,” he said. “It’s been a huge benefit. The only real issue, and I’m not sure if it’s the same for other manufacturers, is because we’re able to run faster and brake later, it’s a lot harder on the brakes. They get extremely hot. Because the tires aren’t dropping off in performance as much, our brakes are.
“But overall it’s been great for us. Now if I want to make a move on the outside, I have that much more confidence. Now, the tires are going to hold throughout a long corner. You can race harder.”
This level of positivity will be well received by Michelin, which still believes it can make further strides in improving its product and level of service. As expected, it hasn’t been a completely smooth ride, but Michelin relishes any opportunity to learn, and has demonstrated its ability to work through various issues.
One of the challenges Michelin has had to navigate is that there has been far more wet running during race weekends than normal this season, meaning the amount of useful track time has been cut.
“We don’t really take anything for granted,” Baker said. “But I would like to have had during the course of this season more dry time running. We’ve suffered rain in a far greater percentage of sessions throughout the season than has ever been the case.”
At Watkins Glen, there was also a recurring issue with the way that the tires reacted to the circuit, forcing the tire technicians on hand to do some on-the-fly problem-solving.
“We knew that at some point during the season we were going to get a spanking; we were going to run up against something that would require us to execute some good problem solving skills,” Baker said. “And that’s what materialized at Watkins Glen, when we saw some challenges with the TCR class.
“Our simulations hadn’t accurately portrayed what we saw. What we faced was an unusually high deflection of the tires, something that hadn’t really shown up in the simulation work that we had done, and it showed up specifically in the TCR class. And if we’re honest, this year we didn’t expect them to be so fast. TCRs are, obviously, quite fast front-wheel drivers, with quite a heavy weight bias to the front. And we discovered that the camber and hot pressure recommendations for the operating window that we had given were not sufficient. We needed to significantly reduce the deflection of the tires, particularly the outside of the front-lefts.
“Of course, what happens when you discover that is the teams just freak out there something wrong with the tires, but we were able to show them our post mortem results on tires that had been damaged internally, so that they could understand what we look for. In the end though, it was quite a good race, we broke records, but we had to find a solution in a hurry.”
In 2020 Pilot Challenge will use the same tires, though Baker tells RACER that a development program for the 2021 selection isn’t too far away.
“We will continue with these S8M and S9M tires for the 2020 season,” he said. “We are taking advantage of the significant additional data that we’re getting this season, and that we will acquire in the first part of the 2020 season, to inform the functional specification for the successor to the S8M and S9M series of tires. The development programs will begin sometime during 2020.”