Bridgestone Corporation, the parent company of Bridgestone/Firestone Americas Holding, Inc. (BFAH), has announced that it and Continental AG, based in Hanover, Germany, have agreed to welcome Tokyo-based Yokohama Rubber Company Ltd., into their collaboration on "Support Ring" run flat tire technology. The three companies will cooperate in establishing a global standard for runflat technology. The preexisting collaboration between Bridgestone and Continental spans two complementary runflat systems that are both compatible with conventional wheels: One of the systems, the Self Supporting Runflat Tire (SSR) system, employs a reinforced sidewall to maintain the tire shape in the event of a loss of air pressure. The SSR system is well suited to vehicles with lower aspect ratio tires, especially sporty cars. The other system, the Support Ring system, employs a light-weight metal ring that is mounted on conventional wheels. In the event of a loss of air pressure, the support ring bears the wheel load and secures the tire on the wheel. The Support Ring system can be easily mounted in conventional wheels with existing mounting devices. The Support Ring system is scheduled to go into production in late 2002 by Continental. It is well suited to passenger cars and sport-utility vehicles with higher aspect ratio tires. The support ring can be reused, subject to usage conditions, and it is suited to use on summer tires as well as winter tires. In the first step, Yokohama will obtain the Support Ring technology from Continental and Bridgestone on a license basis. The three companies will exchange related technical information with an eye to further developing the Support Ring Technology and to promoting that system in the marketplace. Yokohama limits its participation to the Support Ring system at present, since it is developing its own SSR technologies. The three companies have been negotiating their three-way collaboration since mid-2002, and their managements expect to conclude a formal agreement by the end of the year.