Michelin is finalizing its tire compound allocations for next year, which will see most IMSA categories run with two different specifications throughout the 2019 seasons.

The French tire giant, which becomes the official tire of IMSA and exclusive tire provider for the DPi, LMP2 and GT Daytona classes of the WeatherTech SportsCar Championship as well as series-wide in Michelin Pilot Challenge and IMSA Prototype Challenge, is close to making final declarations for each of the categories.

Outside of the GT Le Mans class, which remains an open-tire category, Michelin will nominate a single compound, and its associated wet tire, for each event.

“We’re currently in discussions with IMSA about the notion of publishing an anticipated list of which tracks will use which specifications in advance,” Michelin Motorsports North America technical director Ken Payne told Sportscar365.

DPi and LMP2 teams that took part in this week’s sixth and final Michelin On-Track Opportunity, held at Daytona, were utilizing Michelin’s new IMSA-specific medium compound, which will again be in use for January’s season-opening Rolex 24 at Daytona.

Those cars, according to Payne, will also have a hard tire compound that will be allocated at particular tracks throughout the WeatherTech Championship season.

Both tire options in DPi/LMP2 are considered ‘semi-confidential’ and are based off Michelin’s LMP2 tire used in the FIA World Endurance Championship and European Le Mans Series.

“It’s basically the same casing but after initial testing, we have come up with a medium and a hard that are going to be IMSA specific,” Payne said, noting the differences between European and U.S. tracks.

“[U.S. tracks] are not billiard table smooth, so with the extremes we have temperature-wise from frickin’ cold here in Daytona to belting at Lime Rock or Watkins Glen or CTMP in the summer, we’ve found when we were doing early testing with the exact tires they run in WEC that it just didn’t match up very well.

“We have worked with our design team in France to come up with two IMSA-specific variations of those tires.”

GTD cars, as well as the GT4, TCR and LMP3-spec machinery in the Challenge series, meanwhile, will utilize Michelin’s ‘M’ range of commercial tires, split between the S8 and S9 compounds.

Payne said specific declarations will be dependent on track and ambient conditions, although TCR cars will run on S9s for the entire season and LMP3s are currently fitted with S8s on the front and S9s on the rear.

IMSA’s 2019 sporting regulations now require teams to comply with minimum tire pressure and camber specifications if declared by Michelin on any given weekend.

“Something that surprised teams actually is that we don’t have a unique Daytona construction,” Payne said.

“We manage that, one we have a very robust product to start with, but also with our specification of pressure and camber limits.

“As we’ve done these tire familiarization opportunities with the teams, we’re introducing them to our camber and pressure specification approach and working with them to understand how it works with their cars to optimize the setup and make them successful.

“So far, things are going really well.”

When combined with the three specific compounds for each GTLM manufacturer at every event, Payne said they will be stocking more than 35 different tire SKUs on IMSA weekends.

“It’s a little simpler with just one compound in play for [GTD and] GS on a weekend, but still it’s a lot of donuts to juggle,” he said.

Payne said its expansion into the majority of the IMSA paddock has been a positive experience so far.

“There’s been many steep learning curves and I suspect we’ll have a few more yet to come,” he said.

“So far the response from the teams has been really positive. We’re having very active engagement, particularly in the prototype classes, with their engineers and data exchange with our development team in France. It’s all going quite well.”

Challenge Series Set for Tire Allocations

Both Pilot Challenge and IPC are set to see tire allocations for the first time, as part of a cost-savings measure for teams, according to Payne.

Previously, only the WeatherTech Championship had limitations on the number of tires used each weekend.

“We’re going to introduce the concept of tire allocations to the Challenge classes in 2019 as well as a means to help put a lid on operating costs and such,” Payne said.

“We’re working with IMSA to put a proposed allocation for each of the Challenge classes together.”