Can you drive on a flat tyre?
No, and two miles is more than enough to do serious damage. A fully flat tyre is destroyed within a very short distance, and the wheel underneath it is frequently destroyed with it.
There is one exception, and it is the only one: moving a few metres at walking pace to get off a live carriageway or out of a junction is the right call every time. A tyre costs money. Sitting in lane one of a dual carriageway costs considerably more than money.
Beyond that, driving on a flat is a bad trade. You are sacrificing a tyre you could probably have had repaired, quite possibly an alloy wheel as well, in order to avoid a phone call.
What actually happens to the tyre
A tyre is not a rubber ring. It is a pressure vessel, and the air inside it is what carries the car. Take the pressure away and the structure has to carry a load it was never designed to take.
On every revolution the sidewall folds flat under the weight of the vehicle and springs back. At 20mph that is happening several times a second. The rubber and the internal cords generate heat faster than they can shed it, and within a very short distance the internal structure begins to break down. Nothing about this is visible from outside.
That is why a tyre that has been driven flat is treated as a replacement even when it looks recoverable. It is also why a fitter who agrees to plug one is not doing you a favour.
Keep going and the failure becomes obvious rather than internal: the bead comes off the rim, the tyre shreds, and the bare rim starts cutting into the road.
What it does to the wheel
Once the tyre has lost its shape, the load path runs from the car through the rim into a folded sidewall. Alloy wheels are not built for that. They bend at the lip, crack at the spokes, and gouge where the rim contacts the road.
A bent or gouged rim will not seal properly against a new tyre, which means it needs refurbishing or replacing before the car is usable. That is how a puncture bill triples.
What it does to your control of the car
This is the part that matters more than the repair bill.
- Steering. A flat front tyre drags. The car pulls hard towards the flat side, and it pulls hardest exactly when you brake.
- Braking. Stopping distances lengthen considerably, and braking becomes unstable because one corner has almost no grip.
- Cornering. The tyre can roll off the rim entirely mid-corner, at which point you are steering on bare metal.
None of that is theoretical. It is the ordinary behaviour of a car with a deflated tyre, and it gets worse the further you drive.
What to do instead
- Slow down gradually. Do not brake hard and do not swerve. Let the speed come off.
- Get somewhere safe. Off the carriageway, hazards on, as far from live traffic as you can manage. On a motorway or dual carriageway, get out and get behind the barrier.
- Do not attempt a wheel change next to moving traffic, especially on the offside.
- Fit the spare if you have one and it is safe to do so. Note the speed and distance limit printed on a space-saver, usually 50mph.
- If there is no spare, or the tyre is destroyed, call somebody who comes to you. That is exactly what a 24/7 mobile fitter is for.
Our guide on what to do with a flat tyre at the roadside covers the safety side in more detail, including smart motorways with no hard shoulder.
The awkward truth about sealant kits
Most new cars no longer come with a spare wheel. They come with a canister of sealant and a small compressor, and it is worth knowing what that will and will not do.
It works reasonably well on a small puncture in the tread, which is the most common failure. It does nothing at all for a shredded tyre, a sidewall split, a tyre that has come off the rim, or one that has already been driven flat. If your tyre is genuinely destroyed, the sealant kit is not a plan.
Sealant also has to be cleaned out of the tyre before a proper repair can be made, so tell the fitter you have used it rather than letting them find out.
If you are stuck right now
We are out 24 hours a day across Dundee, Perth, Angus, Perthshire and Fife, and we come to the car rather than making you drive it anywhere. Roadside, driveway, work car park or a supermarket bay at midnight; it does not matter where the car has stopped.
Call Matt on 07449 206 581. If you are somewhere exposed, get out of the vehicle and behind a barrier first, then call. The tyre can wait ninety seconds. You cannot.