Tires With Emergency Running Characteristics, Self-Supporting Tire
Tires with Emergency Running Characteristics, Self-Supporting Tire
General Information
Note:
^ Only vehicles with a tire pressure monitoring system are equipped with SST tires. This warns the driver when tire pressure falls below a certain value.
^ Driving can continue at a maximum of 80 km/h up to a distance of 50 km with complete loss of pressure.
Observe the special mounting information for SST tires.
Mixed installation of SST tires and standard tires is not permitted, and not on the same axle. A standard tire can only be installed in exception cases for a short time or a limited driving distance. However, the SST-specific flat running characteristics no longer apply. The driver must be explicitly informed of this.
In an emergency, the responsibility lies with the driver to decide after checking whether the affected tire can be driven farther. See Owners Manual.
Retrofitting only with tires approved for this (EH2 - rim contour).
SST Tires, Construction
A tire pressure monitoring display is necessary when using emergency running tires.
SST tires are identified with a special code (RSC = Runflat System Component) on the side wall.
The identification on the side wall can differ depending on 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 shop Owners 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 (e.g. no tire changing in an area with low visibility or in dangerous conditions).
Braking, steering and driving performance remain for the most part after the tire looses pressure.
A spare wheel is no longer necessary when using SST tires. From a customers point of view, that means: saving space and weight.
Technology in Detail
Standard Tires without Emergency Running Characteristics
- - I - Standard tires with air
- - 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 looses its properties.
SST Tires with Reinforced Side Wall
- - I - SST tires with air
- - II - SST tires without air
- Especially thick side walls 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 self-supporting, reinforced side walls form the basis of SST technology.
- - A - Illustration of SST tire
- - B - Illustration of standard tire
The reinforced side walls, unlike a standard tire, prevent tire flanks from pinching between the road and rim when flat.
Differences in Wheels in H2 and EH2 Version
- The increased hump on the EH2 prevents the SST tire from springing off when pressure is lost.
- EH2 builds up toward the center of the wheel.
- The clearance to the brake is reduced.
SST Tires (RSC = Runflat System Component)
- SST tires are identified with a special code (RSC = Runflat System Component) on the side wall.
Tires with Emergency Running Characteristics, Repairing
General Information
- The wheel must be inspected before mounting, as with conventional wheel/tire systems.
- The wheels should be checked for damage after a flat tire (true running, axial run-out, other damage) because the wheel could be damaged in an emergency by driving through a pothole.
- A damaged wheel should be replaced.
Note:
^ Flat tire sprays may be used on tires with emergency running characteristics (SST).
^ Tires must be replaced after running flat.
^ Observe manufacturers mounting instructions.