Run flat tires have additional structural rigidity built-in, either through stiffer sidewalls or an inner support ring, enabling the tire to bear vehicle weight even when not fully inflated, unlike a conventional tire.
A standard tire relies almost entirely on internal air pressure to give it sufficient rigidity to support a vehicle’s weight. In the event of a puncture, it will collapse as it deflates, making driving difficult or impossible, and necessitating repair or replacement in situ.
While a runflat tire still requires adequate inflation for proper operation, in the event of a puncture or deflation, rather than going completely flat, it retains sufficient structural rigidity to support the vehicle weight. This enables a vehicle to be driven, albeit at limited speeds and distances, to a suitable repair location rather than requiring repair at the roadside.