Michelin Memories: 2009, Acura’s ‘Square’ Tire Revolution

Photo: Rick Dole/Highcroft Racing

While Audi and Peugeot were the dominant forces in LMP1 competition, a bold design concept gave Acura the edge in tire performance throughout the 2009 American Le Mans Series season.

Following two years in LMP2, the automaker stepped up to the top prototype class with the innovative Acura ARX-02a, which featured the introduction of Michelin’s “square” tire fitment.

The Wirth Research-designed car was built to run the same sized rear tire on all four corners, a first in modern prototype racing, with the optimized tires providing seven percent more contact patch.

It came two years prior to LMP1 rivals Audi and Peugeot implementing the same strategy.

“The larger contact patch means more tire on the road and that certainly helps cornering and braking,” said then Michelin North America motorsport technical director Karl Koenigstein.

“You have a wider front tire to spread the load around which helps, but you are braking later and carrying more speed into the corner. 

“You are really working the front tires much harder than before.”

Patron Highcroft Racing and de Ferran Motorsports debuted the revolutionary Acuras in the Mobil 1 Twelve Hours of Sebring, with IndyCar ace Scott Dixon blitzing to the overall pole, ahead of diesel juggernauts Audi and Peugeot.

The Kiwi credited the car’s superior cornering speeds, courtesy of the wide front tires.

“It was definitely nail-biting,” Dixon said at the time. “On the first run you always try to put a time down and they came back and matched that.

“We tried to push as much as we could and luckily this car seems to get quicker and quicker on its tires.”

While both Acura LMP1 cars failed to finish in its debut race, the de Ferran and Highcroft teams went on to claim overall victories in eight of the remaining nine races that year, with Scott Sharp and David Brabham taking the title.

The innovative program, however, was brought to a halt at year’s end, due to lack of competition as well as the global financial crisis, which impacted Acura’s plans to take the car to the 24 Hours of Le Mans.

It also resulted in limited tire development to the “wide fronts” according to Koenigstein.

“The real pity is that the market crash in ’08 and subsequent lack of heavy factory competition meant that we didn’t go for a complete development of the concept with dedicated steer tires,” he said.

“If they had, Acura would have had a two-year head start on the concept vs. Audi, Peugeot and Toyota and it would have been very, very tough to for the competition to catch up.”

The concept was fully proven on the diesel-powered LMP1 cars in 2011, with Benoit Treluyer completing a quintuple stint on the same set of Michelin tires in his Audi R18 TDI en route to victory at the 24 Hours of Le Mans.

John Dagys

John Dagys is the founder and Editor-in-Chief of Sportscar365. Dagys spent eight years as a motorsports correspondent for FOXSports.com and SPEED Channel and has contributed to numerous other motorsports publications worldwide. Contact John