IMSA to Limit GTLM Tire Selections in 2017

IMSA will tighten GTLM tire rules

With an eye towards next year, GT Le Mans teams are set to return to Road Atlanta later this month for an IMSA-sanctioned tire test, aimed to help each manufacturer finalize its single tire selections for the 2017 WeatherTech SportsCar Championship season.

The one-day test, held at the 2.54-mile circuit at the end of October, will be open to all five GTLM manufacturers, where they'll evaluate a range of Michelin tire options, including three medium-cool range temperature tires and two medium-medium temperature tires for 2017 competition.

It's unclear if Porsche, with its new-for-2017 911 GTE car, believed to feature a new mid-rear engine placement, will be present at the test.

This test is understood to be the first of its kind in IMSA, where manufacturers will be able to test tire options that have been designed for their competition, although Michelin has often conducted similar tests in the FIA World Endurance Championship.

"We agreed with IMSA that Road Atlanta is a good venue as the circuit is demanding of tires and well known by the GTLM teams who will have recent data from race week for comparison," said Ken Payne, technical director, motorsports, Michelin North America.

The test, run in partnership by IMSA and Michelin, will determine the Michelin tires each manufacturer will utilize in the entire WeatherTech Championship season next year.

Manufacturers will be able to mix-and-match tire options from Michelin's full range to determine each car's final configuration. While cold and medium options will be evaluated, the entire GTLM field expected to remain on the same hot range temperature tire for next year.

It effectively ends in-season tire developments, which has been a crucial part of the GTLM class.

In 2015, Michelin debuted its "single stint" tires for the Road America and VIR rounds, which delivered a significant performance increase that was created specifically for IMSA's pit stop rules.

This past season saw the French tire manufacturer roll out its 2016 WEC tires at Mazda Raceway Laguna Seca in May, after starting the year off on 2015 specification rubber.

Porsche, meanwhile, reverted to the previous year's medium compound tire prior to the Lime Rock Park round in July, as part of a Balance of Performance adjustment issued by IMSA.

IMSA's change in philosophy of locking in tire selections for each manufacturer will result in WeatherTech Championship teams utilizing different tires than in the WEC next year.

It's understood Michelin is designing longer-lasting multi-stint tires for the WEC to accommodate the championship's further limit on the number of tires used per weekend for 2017.

The change could have a significant impact on teams and manufacturers, such as Ford, Porsche and Ferrari, which all have cars present in both championships, as well as U.S.-based teams, such as Corvette, taking part in the 24 Hours of Le Mans.

When reached by Sportscar365, IMSA declined comment on the upcoming test and its decision to lock tire selections per manufacturer, for next year. John Dagys/Sportscar365.com