FULLERTON, Calif.—The recent naming of Continental Tire the Americas L.L.C. as the official race tire supplier for three of the four Tudor United SportsCar Racing (USRC) series classes will cut into—but not cut out—Mich-elin North America Inc.'s and Yokohama Tire Corp.'s involvement in U.S. endurance racing, officials for the tire companies said.
Continental's role as the tire supplier for the USRC's prototype, prototype challenge and GT Daytona classes will mean the end of Michelin's involvement in the prototype.
It also will mark the end of Yokohama's 5-year-old supply arrangement for the American Le Mans Series' GTC class.
Both Michelin and Yokohama said they intend to stay active in the USRC's GT Le Mans class, which carries over from the ALMS GT class and is based on the GTE class recognized internationally and which retains an open tire specification.
The GTLM class pits European GT-class cars like the Aston Martin Vantage, BMW M4 GT, Ferrari F458 and Porsche 911 GT3 against the top U.S. sports cars like Chevrolet Corvette and Chrysler Viper.
Michelin, Yokohama and Falken Tire Corp. were tire suppliers during the 2013 season, and Michelin and Yokohama both said they intend to continue in 2014.
It's not known at this time whether Falken Tire Corp., which has been supplier to and sponsor of a Porsche 911 team the past several seasons, will continue.
"This class is largely home to automotive manufacturer teams that desire flexibility in creating tire partnerships to develop technologies in racing that eventually find their way to the streets," said Scot Elkins, vice president of competition and technical regulations for the International Motor Sports Association, which covers technical matters for the USRC.
"In many cases, these are mutually beneficial partnerships that have been developed and nurtured over several years," Mr. Elkins added.
Michelin said it was "disappointed" to be excluded from competing for overall race wins but "pleased" that the GT-Le Mans class will provide open tire competition.
"We look forward to racing and continuing to work with the USCR and its other stakeholders to explore more mutually beneficial agreements for the years to come," said Chris Baker, director of motorsports for Michelin North America.
Yokohama also will continue to be the exclusive tire supplier for the IMSA GT3 Cup Challenge for Porsche 911 GT3 cars.
"We believe the formation of the USRC will only strengthen an already great support series. Our involvement will not be affected," said Duane Sampson, Yokohama manager, motorsports.
Separately, the USRC announced that Rolex S.A.'s Tudor watch brand will be the series title sponsor for the 2014-2018 seasons and disclosed a five-year multimedia rights deal with Fox Sports.
Rolex has been Grand-Am Racing's title sponsor since 2000.