Run-Flat Tyres Explained: Meaning, Markings and Replacement

What run-flat means

A conventional tyre relies on air pressure to carry the car's weight. When it punctures, the sidewall collapses and the car must stop. A run-flat tyre has much stiffer, reinforced sidewalls that hold the car up even with little or no air inside. That lets you keep driving, at reduced speed, to a safe place or a tyre fitter.

Michelin states that its run-flat tyres can typically continue for up to 80 km at speeds up to 80 km/h after pressure loss, and that these figures vary with load, outside temperature, road and tyre profile. Other manufacturers give similar guidance. Your car's handbook gives the figure that applies to your vehicle, and you should use it rather than a general number. In UAE summer heat, treat the limits as a maximum, not a target.

Further reading: Michelin Middle East: what are run-flat tyres?

How to tell if your car has run-flat tyres

Look on the sidewall for a run-flat marking. Each manufacturer uses its own term, and the markings below are some of the common ones. Many cars that leave the factory on run-flats also have no spare wheel and no jack, which is another clue.

Further reading: Michelin Middle East: what are run-flat tyres?

Which cars in the UAE use run-flats

BMW and MINI are the makes UAE drivers most often find run-flats on, across many saloons, SUVs and hatchbacks. Some Mercedes-Benz, Lexus and other premium models also use them, often depending on trim and wheel size. Because fitment varies by model year and option, check the current tyres and the handbook rather than assuming.

Michelin notes that run-flat tyres need a vehicle approved for them, on rims with the right profile, and a tyre pressure monitoring system (TPMS) to warn the driver of pressure loss. The warning matters because the car can feel almost normal on a deflated run-flat. If you ignore it and keep driving, the tyre will be destroyed.

Further reading: Michelin Middle East: what are run-flat tyres?

What to do when a run-flat loses pressure

On a car with run-flats, the first sign of a puncture is usually the TPMS warning rather than a change in how the car feels. When the warning appears, slow down, avoid harsh braking and sharp steering, and plan the shortest route to a fitter or a safe place to stop. Do not exceed the speed and distance limits in your handbook, and reduce them further if the car is heavily loaded or the day is very hot.

If you are unsure how far you have driven since the pressure dropped, tell the fitter. That information decides whether a repair is even possible. If the car is in a safe place, a mobile fitter can come to you instead of you driving further on the flat tyre.

Can a run-flat tyre be repaired?

It depends on the manufacturer and on how the tyre was used after the puncture. Michelin says its ZP tyres can be repaired once by a professional, under the same inspection and repair procedure as a standard tyre, unless the sidewall states they cannot be repaired. Other manufacturers and some car makers advise against repairing run-flats at all.

The main problem is that a run-flat driven while deflated may have internal damage that is not visible from outside. A fitter should remove the tyre from the rim and inspect the inside before deciding. If the tyre was driven any distance at zero pressure, replacement is usually the safer answer. Our puncture repair service will tell you which applies, and the article on whether to repair or replace a punctured tyre explains the general rules.

Further reading: Michelin Middle East: is my tyre repairable?

Replacing run-flats with conventional tyres

Run-flats cost more than conventional tyres and can ride more firmly, so some owners ask about switching. It can be done on many cars, but think it through first, because the car was designed around run-flats:

• You will need a way to deal with a puncture: a space-saver spare with jack and wheel brace, or a sealant and compressor kit. Many run-flat cars have no space for a full spare.
• Keep TPMS working. With conventional tyres, a pressure warning matters even more.
• Replace all four. Michelin recommends four run-flats together on cars designed for them, and mixing run-flat and conventional tyres on the same axle is not advised.
• Check the car maker's guidance and your insurer, as some suspension tuning assumes run-flat sidewalls.
• Michelin recommends not fitting run-flats to a car that was not originally equipped with them.

Further reading: Michelin Middle East: what are run-flat tyres?

Cost, availability and buying run-flats

Run-flats usually cost more than the conventional version of the same size, and the range of models is narrower, especially in large SUV sizes. When you get a quote, check that the run-flat marking and any car-maker approval marking (such as the BMW star) match what is on the car now.

800 Motor supplies and fits run-flat tyres in Dubai and across Sharjah, Abu Dhabi and Ajman, at home, at work or at a partner centre. Fitting run-flats needs the right equipment because the stiff sidewalls are harder to mount, so tell the advisor your car has them. You can compare run-flat options from brands such as Pirelli at the tyre shop, with the price confirmed in the quote.