Michelin IMSA Insider: Tire Collaboration in GTLM

The Old Plan

Michelin shook up the IMSA paddock, especially its technical department in August, 2015 when it introduced a new GT Le Mans ‘low energy track’ tire at Road America in the only class permitting open tire competition.

Rain on Friday limited track action and Porsche’s Earl Bamber, who had never previously visited the four-mile long circuit, got just four laps during Saturday morning practice.

But when qualifying began, Bamber needed just two laps to get everyone’s undivided attention as he smashed the one-year old track record by 1.4 seconds, then immediately pitted.

Ford CGR’s Mike Hull was a keenly interested observer.

While still racing its Daytona Prototype, CGR had tested the Ford GT at Road America earlier in the week as part of its 2015 development and had matched the previous year’s best times. “We looked at each other and said, ‘What was THAT!’” recalled Hull.

In the race, Porsche’s Nick Tandy and Patrick Pilet started at the back and drove through the field to claim the class win, with Tandy shattering the year-old track race lap record by 2.4 seconds.

The following May, the Ford GT took its first win at Laguna Seca with a similar Michelin tire introduction.

Together, with the departure of the Falken team, the only other tire entrant in the open-tire GTLM class, a new plan was implemented for 2017.

A New Plan

Beginning with the 2017 season, IMSA, Michelin and the GTLM teams agreed that absent another tire maker in the class, each GTLM manufacturer would each choose its specification of Michelin soft and medium tire solutions. All would use the same Michelin commercial hot temperature and wet solutions.

Again for 2018, the GTLM class teams locked in their respective Michelin tire codes for the entire season with IMSA.

The tire selection dance then moves to the implementation stage as each team maps out aero and chassis setups and tire strategies for each race based upon the Michelin solutions they have chosen.

This approach represented a fundamental cultural change for Michelin, which had typically introduced new solutions in IMSA as they became available or as the WEC season progressed.

“The agreement to bar mid-season tire introductions and to have each team lock in its solutions for the entire season helped IMSA maintain consistent data for Balance of Performance and class stratifications and saved money for the teams, so we agreed,” said Chris Baker, director of motorsports, Michelin North America.

A New, New Plan for 2019

Now, as the WeatherTech Championship season enters its second half, IMSA, Michelin and the GTLM manufacturers and teams are exploring a new, new plan for 2019.

“BMW, Porsche, Ferrari, Ford, and Corvette are all now racing GTs at Le Mans and the manufacturers would like to use their Michelin WEC tire solutions in IMSA for 2019 so that they can share data with their WEC teams and avoid having to do two sets of tests and simulations,” said Baker.

There is just one catch.

The WEC teams choose their tires (now also locked in by WEC) based upon testing at European circuits. These tests are typically done by their WEC drivers and engineers with limited input from their IMSA drivers and engineers. The WEC teams choose the tire options, based upon their needs for the WEC circuits, especially Le Mans.

While the cars and tires are the same, the circuits most definitely are not. The challenge is the circuits.

“WEC doesn’t have a track with banking like Daytona, a circuit with bumps like Sebring, or a street circuit like Long Beach,” said Baker.

“Through the years we developed some IMSA-specific tires to help teams that were struggling to make their Le Mans tires work here and even though some have tried to seek permission to substitute or have us develop a new tire, but with IMSA, WEC, the manufacturers, and Michelin all in alignment, IMSA is not about to permit that now.”