A tire built to keep working for a limited distance after a puncture, even without air pressure, is a run-flat tire.
Run-flat tires use reinforced construction to support a vehicle after inflation pressure is lost. The most common self-supporting designs have much stronger sidewalls, allowing the tire to carry the vehicle’s weight temporarily. Other designs use an internal support ring or another insert attached to the wheel.
The benefit is continued mobility: a driver may be able to reach a safe location or repair facility without immediately stopping to change a tire. Many passenger-car run-flats are designed for roughly 50 miles at about 50 mph, though the exact limit depends on the manufacturer, load, road, and damage. A tire-pressure monitoring system is especially important because the loss of pressure may not be obvious from the driver’s seat.
A run-flat is not the same as a self-sealing tire. Self-sealing designs plug or slow small punctures, while run-flats mainly preserve support after pressure is gone. Their compromises can include higher cost, greater weight, harsher ride quality, and limits when the sidewall itself is badly damaged.