A cross-section of a run-flat, or self-supporting tyre.
Run-flat tyres, or RFTs, could be the silver bullet to save your day if you get a puncture.
If you’re an AA member, you could call them, or your nearest workshop, but that could entail a long wait.
You could change out your tyres, but a wheel is a large, bulky item and you might not want to dirty that nice suit or dress you have on.
And let’s face it: no one uses their puncture-repair kits.
What’s special about run-flat tyres?
Run-flats, unlike a conventional pneumatic tyre, are able to support the vehicle’s weight even if all the air in the tyre goes out.
That is down to some special features on a run-flat tyre which enables it to support the full weight of the vehicle.
The most common type of run-flat tyre is the self-supporting tyre.
Self supporting tyre, a type of run flat tyre. Photo courtesy Bridgestone.
Reinforced sidewalls (the part that’s got the tyre’s branding and model name on it) help the self-supporting tyre to retain its shape in the event of air loss.
That allow the car to run at a certain speed and distance before the rubber gives out completely, giving you enough time to get to a petrol station and get help.
This is an important distinction: run-flats cannot be used forever, and can only typically run for about 100km at a maximum of 60km/h before failing completely.
Pros
The pros of such tyres are:
- No need to change tyres or use the puncture repair kit. Simply drive (at a reduced speed) to the nearest petrol station and get help changing the wheel.
- Better driving dynamics and more stability after a puncture, because the tyre still retains its shape.
Cons
- There’s no way to tell if a tyre is punctured, so cars with run-flats are almost always fitted with tyre pressure monitoring systems (TPMS)
- Due to the stiffer sidewalls, ride quality suffers as a result.
- They are costlier to replace
Should you fit a run-flat tyre to your car?
Bearing in mind all the pros and cons above, it’s entirely your decision whether to fit a set of run-flats to your car.
However, just be mindful that you need a TPMS in order not to be duped if your car indeed has a puncture.
How do you identify such tyres?
To check whether your current set of tyres are run flats, look for a code embossed on the tyre’s sidewalls.
There’s no convention on standardised markings for run-flats: it differs by manufacturer.
Continental marks their tyres SSR; Michelin as ZP; Pirelli as RSC; Bridgestone as ROF, RFT or RSC; Yokohama as ZPS.
