When air pressure is lost after a tire punctures or tears, run-flat self-supporting tires maintain their shape and composure, instead of going flat like a traditional tire. Run-flats can be driven for a specified distance at a specified speed with no air pressure — like 50 miles at 55 mph — allowing you to safely reach the nearest service center.

Run-flats eliminate the inconvenience of changing a spare tire on the side of a busy road or during dangerous weather after a sudden loss of tire pressure. Cars equipped with run-flats will have a tire pressure monitoring system to let the driver know when tire pressure is lost so you’re not unknowingly driving around on a bum tire.

Run-flats are commonly used on sports cars because of space limitations, where a spare tire simply won’t fit. Some minivans also use run-flat tires, like the Honda Odyssey and Toyota Sienna, as do many luxury and sport sedans.

While the safety of run-flats is undeniable, they do have a few caveats — one being their replacement cost, which is often more expensive than a traditional tire. Some replacement run-flat tires are also harder to find.

Michelin PAX run-flat tires are optional equipment on the Honda Odyssey Touring and Acura RL; they’re a different style of run-flats, though. Replacement Michelin PAX run-flat tires are only available through authorized Michelin locations and car dealerships that have special equipment and training to service the PAX tires. They do, however, allow you to travel up to 125 miles at 50 mph on a tire with no air pressure, which is longer than most run-flats.

Answered by Joe Bruzek on January 17, 2008 in How Does That Work? , What Does This Mean? | Permalink

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