Run Flat Tyres Explained

A run flat tyre has a stiff, reinforced sidewall that can hold the car up for a limited distance after it loses air. Instead of changing a wheel at the roadside, you drive carefully to a garage. Many cars, especially BMW, Mini and some Mercedes models, leave the factory on them.

How to tell if your car has run flats

Look for a run flat marking on the sidewall. Each tyre maker uses its own:

• RFTBridgestone
• ROFGoodyear, Dunlop
• SSRContinental
• ZPMichelin
• EMTGoodyear
• DSSTDunlop

Other clues: there is no spare wheel in the boot, your car has a tyre pressure warning light, and the handbook mentions run flat tyres.

How far can you drive on a flat run flat?

Typically around 50 miles at up to 50mph, but check the tyre maker's figures for yours. A heavy load, a hot day or a long motorway run all shorten it. Treat it as a way to reach a garage, not a way to finish your journey.

Why the pressure warning matters

Because the sidewall holds its shape, you may not feel a puncture at all. Cars with run flats rely on a tyre pressure monitoring system to tell you. If the warning light comes on, slow down and get the tyre checked. If the system has a fault, get it fixed, because without it you can drive on a flat tyre without knowing.

Can a run flat be repaired?

It depends on the tyre maker and on how far the tyre was driven without air. Driving deflated can damage the inside of the tyre where you cannot see it, so many garages will not repair a run flat, and some makers say not to. Ask your garage, and expect to replace it in many cases.

Can I swap run flats for standard tyres?

You can, but think it through first:

• you will have no spare, so you need a spare wheel or a puncture repair kit in the car;
• car makers advise against mixing run flat and standard tyres, and you should never mix them on the same axle;
• the car's suspension was set up for run flats, so it may ride and handle a little differently.

Many drivers swap because run flats can ride more firmly. Newer run flat designs are much more comfortable than early ones, so a modern run flat may solve the problem without giving up the safety benefit.

Buying run flats

Replace like for like where you can: same size, load index and speed rating, and a run flat to replace a run flat. On our results pages, use the run flat filter to show only run flat tyres in your size. Our guide Tyre markings explained covers the other codes on the sidewall.

If your car has run flats and you need a tyre quickly, order before 1pm, Monday to Friday, and we dispatch the same day, tracked with DHL.