Always replace Run-flat tyres with Run-flat tyres
...And don’t retro-fit run-flat tyres without a Tyre
Pressure Monitoring System.
Run-flat tyres are an integral part of the design of an
increasing number of cars. They provide significant
safety features but they are more expensive that the
same sized non run-flat tyres and punctures in them
cannot be repaired. This sometimes encourages car owners
to consider fitting regular tyres instead. This is not a
good idea.
The side walls of run-flat tyres are much stiffer than
those of traditional tyres and the vehicle manufacturer
has incorporated this into the suspension design of the
car. Fitting non run-flat tyres could seriously effect
the handling quality of the car and it could become
unstable, particularly in extreme conditions.
Conversely, because run-flat tyres are more convenient,
as well as safer, car owners sometimes consider
retro-fitting them to cars that were not designed to run
on them. This is also not a good idea.
Cars with run-flat tyres always have a tyre pressure
monitoring system (TPMS) fitted. This device alerts the
driver to a loss of tyre so that the vehicle’s speed can
be reduced to the recommended maximum of 50mph, in a low
pressure situation. This prevents over-heating of the
deflated tyre which is critical to the deflated
performance and to safely concluding the journey.
Without the TPMS the driver might not notice the loss of
pressure and continue without reducing speed. This would
cause the deflated tyre to overheat, possible with
dangerous consequences.
So the message is clear. If your car is fitted with
run-flat tyres you should always replace with run-flat
tyres. If your car doesn’t have run-flat tyres you
should not replace with run-flat tyres. However it is
acceptable to use run-flat tyres from a different
manufacturer, as long as other issues such as
directionality and asymmetry are complied with. |
