run-flat tires 
With conventional tires, when all the air has escaped, the vehicle cannot safely continue down the road. Run-flat technology helps solve this problem by supporting the vehicle long enough to get to a service location or the original destination safely without damaging the tire or the wheel.

Some run-flat designs simply add enough sidewall stiffness to low-profile tires to operate at conservative speeds without air. Newer designs incorporate a composite liner around the wheel inside the tire to add support if air pressure is lost.

Michelin is testing a tire and wheel assembly that is a fully composite construction and requires no inflation at all. Although that technology is a few years off, the benefits of increased vehicle safety and fuel economy are driving even more research.

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