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Servicing tyres with run-flat capability > < Self supporting tyres (SST) with run-flat capability

A5

Design of an SST tyre
Design of an SST tyre
Removing and fitting run-flat tyres → Chapter
If run-flat tyres are used, a tyre pressure monitor display must be fitted.
Tyre damage and the resulting loss of pressure are not readily visible.
   
SST tyres are labelled on the sidewall with a special RSC symbol (= Runflat System Component).
The markings on the sidewall of a run-flat tyre may differ according to manufacturer.
A self supporting tyre has run-flat properties in the event of a pressure loss. In the event of a puncture, the vehicle can be driven to the nearest workshop subject to certain restrictions (see → Owner's Manual.
Benefits
SST tyres can be driven for 50 km at up to 80 km/h even after a complete loss of pressure.
Driving style, vehicle speed, road surface, weather conditions, tyre condition and tyre load all affect the distance that can be driven with a puncture.
With an SST tyre, it is not necessary to change the wheel immediately even with the tyre completely deflated (i.e. you don't need to stop the vehicle in a dangerous place or in conditions of poor visibility).
The braking, steering and driving response are virtually unimpaired even with the tyre completely deflated.
You no longer need a spare wheel if SST tyres are fitted. From the customer's point of view, the benefits are savings in space and a lighter vehicle.
Technology in detail
Standard tyres without run-flat properties
  A44-10067
–  -I- Normal tyre with air
–  -II- Normal tyre without air
–  If the normal tyre loses air, the rim presses heavily against the sidewall. The rubber becomes very hot and deteriorates quickly when rolling flat.
SST tyre with reinforced sidewall
SST technology is based on self-supporting reinforced sidewalls.
  A44-10068
–  -I- SST tyre with air
–  -II- SST tyre without air
–  Particularly thick sidewalls -A- support the airless tyre on a standard rim and the vehicle remains manoeuvrable. A special rubber compound strengthens the tyre and bears the weight of the vehicle in the event of a puncture.
The sidewalls on the SST tyre are reinforced to prevent pinching of the tyre between the road and the wheel rim in the event of a puncture.
Differences between H2 and EH2 extended hump rim designs
t  EH2 - the extended hump prevents unseating of the SST tyre after a loss of pressure.
t  The hump on an EH2 extended hump rim is steeper and nearer the centre of the wheel.
  WARNING
The clearance from the brake is reduced.
  A44-10069

Servicing tyres with run-flat capability > < Self supporting tyres (SST) with run-flat capability