MASTERING THE RUN-FLAT TECHNOLOGY
Run-Flat technology is exactly as it sounds – it allows your car to keep on running after a puncture or sudden air loss. Even when the tyre is completely deflated, you can keep on going for at least 80 km at up to 80 km/h.
WHAT HAPPENS WHEN A TYRE DEFLATES?
When a conventional tyre gets a puncture, the sidewalls collapse and continuous driving forces the tyre to detach from the wheel rim, causing it to quickly overheat. The result is a lack of control in steering and braking.
Run-Flat tyres, however, have special inserts to support the sidewalls if the tyre loses air.
These bend as required to distribute the forces of compression and tension caused by the car’s weight, even if the tyre has totally deflated.
WHAT IS RUN-FLAT TECHNOLOGY ABOUT?
The ingenuity behind this is all to do with the tyre’s reinforced sidewalls. Highly resilient rubber inserts support the weight of the car even when the air pressure, which is what normally does this job, is gone.
Under-inflation is the leading cause of tyre failure. It reduces tyre load capacity and allows for excessive sidewall flexing, resulting in high heat generation. Maintaining proper inflation is the single most important thing that the tyre owner can do to ensure tyre durability and maximum tread life. Pressure checks should be made when the tyres are cold. The recommended inflation pressure of the Run-Flat tyre is indicated in the vehicle owner’s manual and on the sidewall of the tyre.
Legal rules for tyre tread wear apply to Run-Flat tyres, which is 1 mm in RSA.
The Manufacturers Run-Flat tyres fitted on a vehicle must carry a minimum speed rating as shown in the vehicle documents. Any Run-Flat tyre must be replaced with a Run-Flat tyre of identical type, size and speed rating.
‘LOW AND FLAT TYRE’ WARNING INDICATOR
If the ‘flat tyre’ warning appears on the TPMS (tyre pressure monitoring system), if fitted, then it is important to determine the cause of this as soon as convenient. The driver should check the inflation pressure on all tyres and if any are below the vehicle’s manual recommendation then inflation pressure should be corrected. If the ‘flat tyre’ warning appears again then a visit to the vehicle’s dealer or to another tyre or car dealer to have the system inspected should be made.
Due to the design of the tyre, the driver will probably not feel a major difference in the ride when the tyre is deflated. But, if low or zero inflation conditions are indicated by the TPMS, he should limit his speed to 80 km/h maximum and avoid hard cornering and severe handling manoeuvres.
REPAIR OF RUN-FLAT TYRES
Unless otherwise specified in the car owner’s manual, a Run-Flat tyre can be repaired by a qualified tyre professional after a thorough inspection and analysis of the tyre history.
In case of doubt, the tyre should not be repaired. The professional repairing the tyre is in any case responsible for his repair work.
Manufacturers does not support tyre repairs under the following conditions:
· if repairs are done outside the tread area.
· if the tyre sidewall area is damaged inside or outside of the tyre by a sharp object:
this damage could have damaged the supporting insert and would thus substantially reduce Run-Flat
distance or otherwise reduce the tyre life.
· if the tyre has been run at low or zero pressure (with warning alarm active) for a long distance or at too high a speed. This can be identified through driver feedback, worn appearance of the external tyre shoulder or upper sidewall, innerliner damage or a rough appearance.
· if there is any damage that would make a standard tyre irreparable.
If replacement is necessary, a Run-Flat tyre of identical type, size and description must be used to maintain the extended mobility feature of the vehicle.
MIXING OF RUN-FLAT AND REGULAR TYRES
It is strongly recommended not to mix Run-Flat tyres and regular tyres on the same vehicle.