A run flat tire can run without air pressure while allowing the driver to maintain steering control.
Intended to allow drivers to continue driving after a puncture, run flat tires were developed for military and specialized armoured vehicles. Over the past 50 years run flat tires have moved into the mainstream and come as Original Equipment on an assortment of luxury and high-end vehicles. With car manufacturers opting to reduce the need for spare tires, and their associated weight, run flat tires are becoming increasingly common.
A self-supporting run flat tire has a stiffer sidewall that allows it to sustain the weight of the vehicle if required. While run flat tires do not require specialized wheels; they do need an active Tire Pressure Monitoring System to ensure that the driver is aware a puncture has occurred. Over the years self-supporting tires have come a long way from the rigid rides of the past. Manufacturers use a variety of compounds to create the feel of a smooth all-season tire with the security of the run-flat technology.
Tires are mounted on wheels equipped with a special support ring that will carry the vehicle load in the event of a puncture. These wheels require special training and equipment to facilitate changeovers.
Run Flat tires are not intended for extended use after a puncture.