Bridgestone Team | 5 min read 

Run flat tires are tires on which you can continue driving after a puncture, so you can reach an auto shop or safely pull over to change your tire—no need to stop immediately on the roadside.

You shouldn’t drive on them endlessly, though. Always check your manufacturer’s specifications for maximum distance and speed. Bridgestone run-flat tires let you keep driving after a loss of inflation pressure for up to 50 miles (80 km) at speeds up to 50 mph (80 km/h).

There are two main types of run flat tire systems: the self-supporting system and the support ring system. In most self-supporting run flat tire systems, the sidewalls are reinforced to keep supporting your car even if you lose air pressure. This means you can drive to safety at the specific speed and distance the manufacturer recommends.

Support ring run flat tire systems use a ring of firm rubber or another structure under the tread to support the car’s weight when tire pressure drops. Because run flat tires are designed to keep working when “flat,” your car needs to be equipped with a Tire Pressure Monitoring System (TPMS). TPMS alerts you instantly if tire pressure drops. Without TPMS, you might drive on an underinflated tire and risk hidden damage.

Annotate a cross-section showing reinforced sidewalls in a self-supporting run flat. Include callouts for normal inflation vs. zero pressure.

Annotate a cross-section highlighting the support ring beneath the tread in a support-ring run flat system.

Self-Supporting vs. Support-Ring: Pros & Cons

Since they continue performing even though they’re “flat,” all run flat tires, regardless of the specific system type, may only be used on a vehicle equipped with a Tire Pressure Monitoring System (TPMS). The TPMS alerts you as soon as one of your tires loses pressure. Without it, you might not know you were driving on an underinflated tire.

You don’t have to change your tire in dangerous or uncomfortable conditions. That’s one of the biggest benefits of run flat tires and why they were designed. With conventional tires, you often need to replace a flat on the spot, or call for a tow. Run flats give you extra peace of mind.

In a puncture situation, run flats are more stable than conventional tires. Since they’re made to support your vehicle even when they contain no air, run flat tires will help you maintain better control in a complete air loss situation than conventional tires.

As safety climbs the list of what matters most to drivers, run flat tires keep growing in popularity. Since run flat tires work reliably with interconnected technologies like TPMS, it may only be a matter of time before they become the norm rather than the exception in new vehicles.