How long can you drive on a run-flat tyre?

What a run-flat actually does

A run-flat tyre has reinforced sidewalls stiff enough to carry the car for a limited distance after it loses pressure. The point isn’t to let you carry on with your journey — it’s to get you off a live lane and somewhere safe without stopping on the hard shoulder to fit a spare (which run-flat-equipped cars usually don’t carry).

The 50/50 rule of thumb — and its small print

Most manufacturers quote around 50 miles at up to 50 mph after a pressure warning. Your car’s handbook gives the exact figure and it varies by brand — some quote less. Several things shrink that allowance considerably:

• Load — a full car, a boot full of luggage or a caravan on the back stresses a deflated run-flat much harder.
• Speed and driving style — hard cornering and braking flex the sidewall the reinforcement is trying to protect.
• How flat it actually is — a slow leak caught early is a different situation from a tyre at zero pressure.

Treat the figure as a maximum for reaching a safe place, not a target. The further you drive on it, the more damage you do.

The bit people don’t expect: it usually can’t be repaired

Once a run-flat has been driven on while deflated, the sidewall structure has been working in exactly the way it was designed to do once. Most tyre manufacturers say a run-flat driven flat must be replaced, and the British repair standard (BS AU159) rules out repairs on any tyre that’s been run deflated — the internal damage can’t be reliably assessed. Budget for a replacement, not a repair.

Replacing one: like for like

If your car came with run-flats, replace like with like unless you know what you’re changing. The suspension is usually tuned around the stiffer sidewalls, and without a spare wheel or repair kit in the car, a conventional tyre leaves you with no backup at all. Keep the same type on the same axle at minimum.

When you get a quote from us, run-flats are clearly badged in the tyre list so you can replace like-for-like without guesswork — and because we come to you, a run-flat that’s already done its 50 miles doesn’t need to do any more. If you’re stopped somewhere right now, our 24/7 emergency replacement covers exactly this; if you’ve made it home, planned mobile fitting is the calmer option.