Run-Flat Tire, Structure And Identification, SST Tire

A Tire Pressure Monitoring Display Is Necessary When Using Run-Flat Tires.

Tire Damage and the Pressure Loss Resulting from It Is Not Always Recognizable.

SST tires are identified with a special code (RSC = Run-flat System Component) on the side wall.

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

The Identification on the Side Wall of Run-Flat Tires Can Differ Depending on the Manufacturer.

Self-Supporting Tire stands for a tire system with emergency running characteristics in the event of a loss of pressure. In the event of a flat tire, the driver can continue driving to a limited extent to the next workshop Owner's Manual.

Advantage 

SST tires make it possible to drive up to 50 km at a maximum of 80 km/h even with a complete loss of pressure.

Driving style, speed, road surface, weather conditions, tire condition and tire load influence the distance.

With SST tires, it is not necessary to immediately change a tire when it suffers from a complete loss of pressure (for example no tire changing in an area with low visibility or in dangerous conditions).

Braking, steering and driving performance remain for the most part even after the tire loses pressure.

A spare wheel is no longer necessary when using SST tires. From the view of the customer, this means: saving space and weight.

Assembly 

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

1  - Bead with bead bundle

2  - Sidewall

3  - Sidewall reinforcement

4  - Rim with extended hump (EH2) on both sides - required when using run-flat tires

Technology in Detail 

Standard Tires without Emergency Running Characteristics

-- -I  - standard tires with air.

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

-- -II  - standard tires without air.

-- If the standard tire loses air, the rim presses the side wall together. The rubber in a flat tire is heated strongly and quickly loses its properties.

SST Tires with Reinforced Side Wall 

The self-supporting, reinforced side walls form the basis of SST technology.

-- -I- SST tires with air.

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

-- -II  - SST tires without air.

-- Especially thick side walls -A- support the empty tires on a standard rim and the vehicle remains maneuverable. A special rubber mixture reinforces the tires and supports the vehicle in an emergency.

The reinforced side walls, unlike a standard tire, prevent the tire flanks from pinching between the road and rim when flat.

Difference in Version H2 and EJ2 Extended Hump Rim 

• The increased hump on the EH2 Extended Hump Rim prevents the SST tire from springing off when pressure is lost.
• EH2 builds up toward the center of the wheel.