The Complete Guide To Run Flat Tyres
Here at Tyre Shopper, we have come up with a definitive guide, answering the questions you need to know to completely understand Run Flat Tyres.
As times are changing and technology is increasing, more and more car manufacturers are fitting their vehicles with Run Flat tyres as standard, such as BMW with the Mini and new 5 series.
What Is Run Flat Technology?
Run Flat technology allows your car to keep on running after a puncture or blow out, even when the tyre is completely deflated. Self-supporting Run Flat tyres are designed to provide a run-on period following deflation. The range of the tyre when running on flat is dependent on the condition of use (i.e. vehicle load, vehicle speed and driving conditions). However you should be able to keep on going for a minimum of 50 miles at a constant speed of no more than 50mph.
Run Flat tyres introduce a new era of safer motoring on our roads. No longer will drivers have to worry about being stranded or late because of a puncture, or even worse having to deal with a potentially life threatening blow out. Changing tyres on the hard shoulder will be a thing of the past with Run Flat Tyres.
The ingenuity behind this is all to do with the tyre’s reinforced sidewalls. The highly resilient rubber inserts support the weight of the car even when the air pressure, which normally does this job, is gone.
Is My Vehicle Suited For Run Flat Tyres?
Always consult the vehicle or tyre manufacturer regarding which vehicles are suitable for the fitment of Run Flat tyres. These tyres may only be fitted to vehicles equipped with a tyre pressuring monitoring system (TPMS).
Can I Replace My Run-Flat Tyre With A Conventional Tyre?
The fitting of conventional tyres to vehicles originally fitted with Run Flat tyres will remove the vehicle’s Run Flat capability. They will also have no spare tyre. This could potentially leave the driver immobile in the case of a deflation, and could compromise handling of their vehicle.
It is therefore recommended to consult with the vehicle manufacturer or tyre manufacturer before replacing a Run Flat tyre with a conventional tyre on such vehicles.
Can I Mix Run-Flat Tyres With Conventional Tyres?
The handling characteristics of Run Flat tyres are different to that of conventional tyres and therefore must not be intermixed on a vehicle.
Can I Mix Different Brands Of Run Flat tyres?
As with standard tyres there may be different characteristics between different makes of Run Flat tyres. It is therefore advisable to consult the tyre manufacturer regarding mixing different brands. It is recommended that the same make and pattern of tyre is fitted across the axle of the vehicle.
Do Run Flat Tyres Have An Increased Tyre Life?
The tread rubber compound used in Run Flat tyres is generally the same or similar to that used in conventional tyres. Therefore, tyre wear rates between the two tyre types should be similar. It is important to note that the best tyre performance is achieved by maintaining correct inflation pressures for the loads and vehicle’s use.
Are Run Flat Tyres Suitable When Towing Another Vehicle?
When Run Flat tyres are fitted to towing vehicles different issues come into play. In their inflated condition Run Flat tyres may be used in the same way as a standard pneumatic tyre. Any experienced touring caravaner knows that the stability between their car and caravan is of primary importance to road safety. Whilst a deflated Run Flat tyre is designed to cope with the demands of the solo vehicle, the additional mass of a caravan/trailer will subject the tyre to higher stress levels and impact on the tyre’s inbuilt lateral stability.
The consequence of this is that even travelling at a restricted speed of 50mph may negatively affect the stability of the car/caravan combination and reduce road safety. To avoid this potential hazard, it is recommended that the distance travelled and maximum speed on the deflated Run Flat tyre be reduced. As the vehicle itself has an influence on the tyre’s performance, please refer to the vehicle manufacturer’s handbook for further information.
Can I Fit Run Flat Tyres To My Caravan Or Trailer?
Run Flat tyres must only be fitted to vehicles which have a tyre pressure monitoring system (TPMS) as a visual/audible warning to drivers of a deflating tyre. As yet no caravans or trailers are equipped with TPMS systems; hence they should not be fitted with Run Flat tyres.
Flat Tyre Facts
- 7 out of 8 of European drivers rate Run Flat tyres above any other technological innovation made for the road
- 58% have experienced more than one flat tyre or puncture
- 25% feel unable to replace a flat tyre themselves
- An average of 27% have had a puncture whilst driving in the city 20% have had punctures on country roads
- 24% have had a puncture on the motorway
Can My Run Flat Tyres Be Repaired?
Here is what the manufacturers say:
It depends on how far and at what speed the car was driven after the puncture was sustained. Repair is possible only if deemed so by the tyre sales store. However it is strongly recommended that the tyre is replaced as its durability will have been weakened after being repaired. - Bridgestone.
SSR (Self Supporting Runflat) tyres which have been used in a deflated condition are subsequently not suitable for repair. - Continental
Goodyear recommends that Run Flat tyres be changed after they have been used under deflated conditions. However Goodyear understands that customers might want to repair their Run Flat tyres for cost reasons. - Goodyear
Damage to the sidewall could occur if you continue to drive on the flat tyre for more than the recommended distance (approx. 100 miles) or over the maximum speed of 50mph. - Michelin
A tyre should always be changed and not repaired after a loss of pressure, as it is not always possible to establish the time and conditions under which the tyre has been used with insufficient inflation pressure. - Pirelli
15 Aug 2018
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