What is a run flat tire?

A run-flat tire is either a pneumatic vehicle tire specifically designed to resist the negative effects of deflation when punctured or the term may also refer to a standard wheel and tire that has a run-flat device affixed, see ‘auxiliary-supported’ below. This enables the vehicle to continue to be driven (at reduced speeds, typically under 55 mph) for limited distances (up to 10 mi depending on the tire/device).