Insight: How Michelin Developed its Newest Hypercar/GTP Tire Range

Sportscar365 goes behind the scenes with Michelin at Paul Ricard tire test…

You probably don’t think about it nearly enough, but tires are one of the most critical components in all of motorsport. That goes beyond the obvious ‘a car can’t move without them,’ of course.

Just think how often tire strategy or tire management has dictated the outcome to a race. Or, on the more extreme end, how many punctures have brutally ended a driver’s dream of a race victory or a championship.

With that in mind, it should come as no surprise that the development of tires is an area of tremendous importance. It very much happens in the background, but tire companies invest significant amounts of manpower and capital to bring the best possible product to teams at the race track.

Arguably chief amongst these companies is Michelin, the French stalwarts of motorsport that have been active across various disciplines of racing for more than one-hundred years. For some context, the first-ever edition of the 24 Hours of Le Mans was won by a Michelin-shod Chenard et Walcker.

Fast forward a century and Michelin has maintained a very strong track record at the French endurance classic. Since 1998, every single car that won Le Mans has done so with an image of Bibendum proudly waving on the sidewall of its tires.

At present, it remains the exclusive supplier for both the FIA World Endurance Championship’s Hypercar class as well as the GTP category that headlines the IMSA WeatherTech SportsCar Championship.

For those two categories, Michelin on Thursday revealed a brand new specification of tire that will be used in the top class of both championships next year, dubbed the Pilot Sport Endurance 2026.

The introduction of the new tires comes following an extensive testing and development process, which will wrap up with a test at Watkins Glen International the day after this month’s Sahlen’s Six Hours of the Glen.

To find out more about the development process for the new tire range, Sportscar365 went behind the scenes at a Michelin-organized test held at Circuit Paul Ricard, which was attended by a number of WEC Hypercar manufacturers.

In total, six brands turned laps throughout the day, with that list including Alpine, BMW, Cadillac, Ferrari, Toyota (with its No. 7 GR010 Hybrid decked out in the 40th anniversary livery that will be in action at Le Mans next week) and Porsche.

Peugeot was absent, as was Aston Martin, although it was confirmed by Michelin representatives that the latter’s absence was a result of the testing crash it suffered at Spa-Francorchamps in April.

Paul Ricard was one of a number of venues that had been selected by Michelin to test for its 2026 tire range, with testing also having taken place at circuits such as Qatar’s Lusail International Circuit and Sebring International Raceway.

As Pierre Alves, Michelin’s endurance program manager, explained, the characteristics of the Le Castellet circuit made it an unmissable fixture on its testing calendar.

“The specificity of Le Castellet is that we have the Mistral, a very long straight,” Alves told invited media, including Sportscar365.

“We are testing today without the chicane because what we want to achieve is a high speed and also a very heavy load on the tires.

“So on the long straight we can identify some points and some characteristics to check what we are seeing in Le Mans, in Fuji and Daytona.

“After that, [we have] what is the most demanding corner that we have in our range of tracks where we test: Signes. There we have a huge constraint on the tire.”

The high-speed nature of the circuit plus the timing of the test, coming exactly a month before Le Mans, also made the test very attractive for teams to get a chance of some on-track running in before the blue-riband event, especially as it does not detract from the eight days of testing each manufacturer is permitted this season as per the sporting regulations.

However, this does not mean that a manufacturer can show up to one of these tire tests with a run plan of their own and stick to their own schedule. In fact, it’s quite the opposite.

“We opened the track at 9 a.m. [and] until 9:45 a.m. it's their track,” said Alves.

“9:45 a.m, the cars are ours. So at 9:45 the car has to be ready to test the tires and we ask them to not change the setup of the car.”

From there, each of the manufacturers will be part of a rigorous testing program that, in this case, was built specifically around the Medium compound tire.

Based on knowledge gathered previously, Michelin arrived at Le Castellet with three different variants on the Medium tire that it would seek to gain further knowledge about, with the end goal of selecting one compound to be used as the Medium in 2026.

The goal for the Paul Ricard test was therefore to gain feedback from all manufacturers involved on each of the three compounds so that it could make the most well-informed decision when the so-called ‘design freeze’ kicks in next month ahead of the production process.

As Alves explained, the way Michelin would achieve this is by cycling the variants throughout the attending manufacturers in various stages, with each driver then supplying feedback.

“At the end of the day, they would have tested the same thing, just not at the same time,” said Alves. “We try to mix. So usually how it works, the first run, we start with the reference [tire], which is what we are using [this season].

“We do a normal run with the same amount of laps. I think the short run here is seven or eight laps.

“We have to do seven laps on the reference [tire]. After that, test option A, option B [and then] the reference again. Afterwards we can compare it. This is the first loop of the development. And then maybe next door in the next garage, they will do C and B and the reference. We are doing different options, but with the same number of laps.”

Then, after lunch and some careful analysis from Michelin’s engineers, the remainder of the program focuses on long runs, once again in comparison with the currently used reference tire before and after.

In this case, a long run is categorized as a stint of 15 laps on the same tire. In this way, an hour-long race stint is essentially cut up into segments with an eye on time constraints.

A trip down the pit lane in the afternoon allowed for an opportunity to witness the aforementioned feedback process first hand when Sheldon van der Linde brought his BMW M Hybrid V8 into the garage after a run.

Just a few moments later, while the South African was still sitting behind the wheel, a Michelin engineer approached and handed him a tablet with a list of questions to fill out.

“In order to have a good read on their comments, obviously we have their comments on our software, but also we want to objectify what they say,” the engineer later explained.

“When they are saying, for example, it's a bit more stable, we want to know what's the real amount of stability from one option to another. So we created a grid in which they are going to note and rank. So based on the different criteria, they are going to rank, for example, the lateral grip from a scale from minus three to three, if it's worse or better for them.

“So we know, for example, if he says that both options have more grip, we know that maybe one option has got really a lot more grip than the other.

“And then we also do it for the car balance, so either the oversteer side or understeer side in different phases. So high speed corners, low speed corners, [corner] entry, apex, [corner] exit. Start of the run, end of the run. And then we're going to link it with data analysis to see if it's going in the same direction and everything.

“The idea is that it can change from one track condition to another, from one driver to another, so we're trying to evaluate and then we're going have all the results, put the results in common from all the teams and then give a real answer to the designers.”

Michelin has set out a number of targets that it aims to achieve with the new range of tires, with improved longevity, less tire wear and quicker warmup all key areas of improvement.

When it comes to the warmup, the goal is for the Pilot Sport Endurance 2026 to provide a gain of three to five seconds on the first lap compared to the tires that are currently used, with that improvement measured between the second sector of the out lap and the second sector of the first flying lap.

Meanwhile, while Michelin says the tires would have the capability for triple or quadruple stints, for WEC’s standard six-hour format double stinting a full set would be ideal. This means teams would be supplied with three sets for such a race distance, thus reducing the allocation with an eye on sustainability.

Sustainability has been a significant focus for the Pilot Sport Endurance 2026, with Michelin stating that these tires will consist of 50 percent recycled or renewable materials.

Cyrille Roget, who serves as the scientific & innovation communication director at Michelin, points out that because there is no commonly defined set of parameters for what counts as recycled or renewable materials, the French firm has gone ahead and set its own “very strict” definitions.

“A renewable material is a material that is biosourced, that can be renewed on the human timescale,” he said. “For example, we invented tires with silica in 1992. Silica basically comes from sand, like glass.

“Sand is not renewable because it takes more than a human life to be renewed. It takes very long for the water to grind the rocks and create sand. So for us, sand is not renewable, so we need to replace silica with something that is renewable on the human timescale.

“What is a recycled material? And again, this is a very strict definition that we apply at Michelin.

“We said a recycled material is a material that has been seen by a consumer, that has been worn or damaged, that becomes a waste, that is transformed into a new material that you can reuse.”

That desire for sustainability has pushed Michelin to commit to some out-of-the-box thinking when it comes to sourcing materials for its 2026 Hypercar/GTP compound, with some of the materials used including reused styrene, biosourced oils such as sunflower oil as well as lemon and orange skins to be used as resins.

Recycled steel is also used, while it has found an unexpected replacement source for the aforementioned silica, which was determined to be non-renewable.

“We can use the skin of rice,” said Roget. “It’s called the rice husk, that can be pyrolyzed [a process to decompose organic materials due to heat in the absence of oxygen] and it creates a material that can replace the silica by the silica coming from the skin of the race.

“Today, this is a waste of the rice industry. It's available in large quantities because you can imagine that with the quantity of rice that is eaten every day on the planet, we have a lot of waste of the rice industry with that skin.

“And that skin can be pyrolyzed and give something that is very close to the silica coming from the sand.”

The figure of 50 percent renewable or recycled components in the new-for-2026 tires is a notable increase compared to the current range of tires, for which that amount is set at 30 percent.

Looking at it from a wider perspective, this is all part of a push from Michelin to achieve a company-wide rate of 100 percent renewable and recycled materials in 2050.

However, for the manufacturers involved in the development of the Pilot Sport Endurance 2026, the far more relevant short-term date is Jan. 24, 2026.

On that day, these new tires will make their race debut when the green flag drops for the Rolex 24 at Daytona. It will be there and then when everyone discovers if these tires are as big a leap forward as all parties involved hope.

One thing is for certain, however. If this peek behind the curtains has taught us anything, it definitely won’t be for a lack of effort.

Photos: Michelin, MPS Agency