Abbreviated to BSR, the Support Ring run-flat system, which has been under development since 2002, will be used by Toyota for use in its new RAV4 for the European market.
As with other run-flat systems the intention is to keep a tyre functioning after loss of air pressure so that the car can continue driving safely, albeit at a reduced speed and for a limited distance.
The support ring is made of rubber, bonded to a lightweight metal ring that is fitted to the wheel inside the tyre. In case of air loss the ring supports the vehicle and fixes the tyre bead onto the wheel rim.
The system is suited for passenger cars and sport-utility vehicles that have high-profile tyres.
Other vehicle manufacturers are expected to follow Toyota’s lead and fit the Bridgestone Support Ring Run-Flat System.