The Michelin run-flat tires fitted to certain BMW products are too heavy, degrade the vehicle's ride, and increase fuel consumption. So says Didier Miraton, who heads up the French tiremaker's Michelin Technology Center.
Miraton has an ulterior motive, of course. He wants to push his employer's PAX run-flat system (pictured to the right), which eschews the super-stiff sidewalls of typical run-flats in favor of an elastomer inner ring and an improved bead design. This design not only allows for improved handling and ride, but also provides over twice the endurance (125 miles vs. 50) after pressure is lost. The downside to such a system is that it requires a special wheel and can only be serviced by trained technicians, where as standard tires can be repaired virtually anywhere in the world.
In our opinion, anyone who's working on a solution to flat tires deserves mad props, since it's one of those nagging century-old problems that an outside observer might think should have been addressed before everyone expended so much energy on the issue of, say, dashboard covers that were hard to the touch.