Tires that can be driven while in a flat state is appearing more and more on new vehicles. As a result, Consumer Reports recently has looked into their practicality and safety.
According to Consumer Reports, there are two types of run flat tires -- self-supporting tires and the Michelin PAX System. Self-supporters feature very stiff sidewalls so that they can carry the vehicle if air is lost. However, the added stiffness added by the sidewalls can cause a harsher ride that many drivers and passengers may not be willing to endure.
Self-supporting tires appear on such vehicles as the Toyota Sienna minivan and the Chevrolet Corvette roadster.
The Michelin PAX System is used on the Honda Odyssey minivan. It uses a special wheel fitted with a ring that supports the tire when there is no air in it. But changing this tire may be difficult because special equipment is needed to do the task. The tire is also expensive: some owners have swapped it out for more conventional tires after a flat due to the cost.
Moreover, the Michelin PAX System assembly is not always in stock at the dealer.
Other issues include more frequent replacement of run-flats as opposed to standard tires.
In general, run-flat seemed to be most used on higher end sports cars, sedans, and cars with limited storage space for a spare tire.
Consumer Reports concluded that run-flat tires provide safety benefits that consumers should consider. Also, the technology to produce and use them is improving while their prices go down.
Our take? One of our writers used to own a Pontiac Sunbird in the '70s. The car didn't have much storage space for a spare tire so the tire would be stored flat. If you needed it, you had to spray a kind of foam type substance into it to inflate it. Needless to say, he hated it. He's happy to see that automakers and tire companies have not neglected owners of smaller cars with limited storage space. and to see that consumer advocate publications are supporting the new innovations.