Michelin IMSA Insider: Vive la Difference

Although 4,256 miles and six time zones apart, the Motul Petit Le Mans at Michelin Raceway Road Atlanta and the iconic 24 Hours of Le Mans, are both beloved and respected by fans and competitors alike.

Here is why:

The Sport

Endurance sports car racing attracts the top manufacturers, teams, drivers, and technical talent to a comprehensive test of technology, performance and strategy, in a wide variety of conditions at the most challenging and iconic circuits. IMSA in 2021 features 18 automotive manufacturers.

The Tracks

At 2.54 miles, a lap at Road Atlanta is less than one-third the distance of an 8.47-mile lap at Circuit de la Sarthe. Three laps at Le Mans are almost exactly the distance of 10 laps at Road Atlanta. The French circuit includes 38 turns, while the shorter Road Atlanta circuit has 12 turns.

While Le Mans is virtually flat, Road Atlanta features more than 125 feet of elevation changes, highlighted by the signature run down the hill from turn 11 to turn 12 to enter the front straightaway.

Lap times are also correspondingly different. At Le Mans, the 2021 pole time was 3:23.9s (203.9 seconds) and the quickest race lap was a 3:27.6 (207.6 seconds).

Race laps at Road Atlanta are typically in the 68-70 seconds per lap range. Teams at Petit Le Mans risk quickly going a lap down if their pace is not strong and can easily lose one or more laps if they encounter any issues.

Sunrise/Sunset

Both events start midday on a Saturday, run through the afternoon and sunset, with Petit Le Mans ending shortly after 10 p.m. The 24 Hours of Le Mans continues through the night, then sunrise and on to finish mid-Sunday afternoon.

Both events feature multiple prototype and production-based GT classes and pro and am drivers to provide a constant mix of cars and classes.

The Pit Differences

Tire warmers are permitted at Le Mans, but not in IMSA competition. That makes out-laps on new tires, a challenge, especially in the cooler fall evening conditions.

The two events have different tire allocations and pit rules. Petit Le Mans follows the IMSA rules, which permit simultaneous refueling and tire changes, while the WEC rules at Le Mans separate fueling from tire changes.

As a result, Le Mans places a premium on multi-stinting tires to save pit stop time, while the ability to change tires while refueling means most IMSA teams typically single stint their tires.

Michelin engineers closely monitor ambient and track temperatures and conditions to help teams optimize their performance as the races progress. Data and insights into performances in changing conditions are fed into Michelin’s development of future road tires. The Official Tire of IMSA since 2019, Michelin has won the last 24 consecutive editions of the 24 Hours of Le Mans.

The Traffic

The past two editions of Petit Le Mans have covered 460 (2020) and 465 (2019) laps respectively, the record (2019) being 1,181.1 miles. In comparison, the most recent Le Mans winners covered 371 (2021) and 382 (2020) laps of the much longer circuit and race duration respectively equaling approximately 3,142 miles (2021) and 3,277 miles (2019).

The shorter Michelin Raceway Road Atlanta track length and race duration puts teams on a highly aggressive pace in constant traffic.

While the two events have different caution period procedures, the two most recent editions of Petit Le Mans have featured long green flag runs, with just 6.5 percent (2020) and 5.4 percent (2019) of the race under cautions, including a massive 224 lap green flag stint in 2019.

The Talent

With third drivers aboard nearly all entries at both events, both fields feature exceptional levels of driving talent from around the world.
The 2021 edition of Petit Le Mans includes several former Le Mans winners, including 2021 overall winners, Mike Conway and Kamui Kobayashi.

Last year, five of the nine DPi drivers on the overall race podium at Petit Le Mans were also Indy 500 winners. Scott Dixon, Alexander Rossi, Helio Castroneves, Juan Pablo Montoya and Simon Pagenaud joined Renger van der Zande, Ryan Briscoe, Ricky Taylor, and Dane Cameron in the post-race celebrations.

Looking Ahead

As PLM prepares to celebrate its 25th year in 2022, Le Mans is preparing for its Centennial in 2023. Two major celebrations roughly eight months apart and fitting recognition of two of endurance sports car racing’s favorite events.