Michelin has been satisfied with the level of progress on its Le Mans Hypercar tires approaching the new formula’s FIA World Endurance Championship debut and is “done with phase one” for its four-wheel-drive range that will be used by Toyota this year.
Michelin’s global motorsport director Matthieu Bonardel told Sportscar365 that the official LMH supplier is “on-time” with its tire development after heading into the winter with a tight testing window for the 2021 season, which was originally due to start Sebring in March but has since been pushed back to Spa-Francorchamps on May 1.
Toyota has so far conducted four major tests with its new GR010 Hybrid LMH car since October, including an around-the-clock endurance run at Paul Ricard last week.
Those tests have enabled Michelin to obtain real-world readings for its four-wheel-drive tire ‘family’, while Bonardel explained there are still “plenty of things to do” for the French company’s rear-wheel-drive range that will be used by Scuderia Cameron Glickenhaus.
“The winter has been as good as we could have reasonably hoped, given a few difficult situations beyond all the restrictions, with the short timing and lack of cars,” said Bonardel.
“What we can be certainly happy with is: the only Hypercar that we had available, the Toyota LMH, was performant and pretty much reliable. And also able to dedicate some time to tire development.
“We’ve done short stints as well as long stints. Only one session [at Aragon] had to be postponed, due to snow conditions. We did not feel it necessary to develop snow tires…
“All the rest was good, mild conditions on tracks which are representative of the medium range. We are on-time with our program, in terms of development.”
Michelin has conducted extensive testing of its soft, medium and harder slick compounds for the four-wheel-drive range.
Bonardel noted that it has also collected enough data for the wet tire, enabling damp weather performance to be inferred despite a lack of Toyota running in that condition.
He explained that Michelin made some slight changes to its front-to-rear tire balance after the first Toyota test at Paul Ricard last October. This was done to achieve a balance suited to the 70 kg weight reduction for LMH cars to bring them in line with LMDh.
“Initial production was not necessarily targeted on that latest weight balance,” said Bonardel.
“Of course, when we put the car which was ready for a slightly different weight distribution, the balance had a little bit more oversteer, and we had to correct it when testing rear and front compounds.
“The simulation was right, but the car changed a little bit due to the regulations, which forced us to improve the rear stability. And now I think we’re at a good level of rear stability, with room to improve it in the next range.
“We are done with phase one for LMH four-wheel-drive. It still gives you plenty of things to do with LMH rear-wheel-drive.”
Michelin is keen to achieve the “same good results” for its rear-wheel-drive LMH tire family, which is being used by the non-hybrid Scuderia Cameron Glickenhaus SCG 007.
Bonardel suggested that there is “a lot more dependence” on simulation data for this tire range, considering the Glickenhaus made its track debut at Vallelunga on February 25 before undergoing a second test at Monza last week.
“Our simulations worked perfectly with Toyota,” said Bonardel. “We were spot-on the target with putting together all the different rigs. We were really proud of all the pre-work done in simulation, with drivers and without, because it could really help us to design the tire for the car.
“If we have the appropriate data from those rear-wheel-drive LMHs, there is no reason why we cannot see the same good results. But it’s still too early to tell.
“As you can imagine, if the car is new then usually you have the basic things to check, like does the tire fit into the wheel arch? Is it touching something or vibrating? You have a whole bunch of things before considering grip and balance.
“The good news is that all this is shared with the ACO and WEC authorities. We know we have to be prepared to make modifications during the first races. We are ready but we’ve got to be prepared for the situation to evolve.”
LMH Machinery “Totally Different” to LMP1
Bonardel predicts that a heavier weight will make the new LMH breed, particularly the hybrid variety, much “harder” on their tires compared with the old LMP1 hybrids.
Michelin expects LMH cars to manage double stints at the shorter Grand Prix-style tracks on the WEC calendar, while tire longevity at Le Mans is currently unknown.
“To compensate for the increased mass, you get to put more aero on, and all that puts more stress on the tire,” said Bonardel. “We see 40-60 percent more stress on the tires, especially the rears.”
LMP1 will continue to be represented in the WEC top category through Alpine Endurance Team, which tested its V8 non-hybrid prototype at Aragon last month.
Michelin is working with Alpine to ensure that the French team’s A480 Gibson LMP1, which is being slowed to compete against LMH, won’t be compromised by using the same ‘grandfathered’ tires that Rebellion Racing used on the same car last season.
“They [the WEC] don’t want us to create or develop tires,” said Bonardel. “The only concern is that cars are still going to be different in the grandfathering.
“It’s not going to be the same car we saw last year, lapping at 3:15 at Le Mans. It’s a bit slower.
“If it’s slower, will the car work in the same fashion? When you are slower, you struggle to put heat in the tires. We want to make sure that, yes, it’s fine and fair to request not to change the tire, which was our target in the last test session.”