NAIL OR SCREW IN YOUR TYRE: CAN IT BE REPAIRED?

The short answer

A tyre with a nail or screw in it can usually be repaired if all of these are true:

• The object is in the central three-quarters of the tread, not the shoulder or the sidewall.
• The hole is small: up to about 6mm across for a car tyre.
• The tyre has not been driven on while flat or very soft.
• The tyre is otherwise healthy: legal tread, no bulges, no exposed cords, no ageing cracks.

Those limits come from British Standard BS AU 159, the UK standard for tyre repairs. A reputable fitter works to it, which is why the answer is sometimes "no" even when the hole looks tiny.

What to do right now

1. Leave the nail or screw in. It is often plugging the hole. Pull it out and a slow leak can become a flat in minutes.
2. Check the pressure. If the tyre is holding air, you have time to arrange a repair. If it is visibly soft or flat, don't drive on it.
3. Don't drive far. Every mile on an under-inflated tyre damages the inside of the sidewall, and that damage is what turns a repairable tyre into scrap.
4. Take a photo showing where the object is on the tyre. It lets a fitter tell you the likely outcome before anyone travels.

When it can't be repaired

• Sidewall or shoulder damage. These areas flex constantly and a repair there will not hold. The tyre has to be replaced.
• A hole that is too big, or a cut or tear instead of a clean puncture.
• Run-flat damage inside. A tyre driven on flat often looks fine outside while the inner liner is scuffed and breaking up. This is only visible with the tyre off the wheel.
• Too close to an earlier repair, or more repairs than the standard allows for that tyre's speed rating.
• Tread at or near the legal limit. There is no sense repairing a tyre that is due for replacement anyway.

What a proper repair looks like

The tyre comes off the wheel and is inspected from the inside. The hole is cleaned out and filled with a combined patch and plug fitted from inside the tyre, which seals the inner liner and fills the channel the object made. The wheel is then rebalanced and refitted.

A string plug pushed in from the outside is not a permanent repair, and neither is a can of sealant. Both can get you moving in an emergency, but the tyre still needs inspecting from the inside afterwards. If you have used sealant, tell your fitter: it can make a permanent repair impossible.

Is it safe to keep driving with a screw in the tyre?

If the tyre is holding pressure, a short, gentle drive to get it dealt with is normally fine. Driving on it for days is a gamble: the object works loose, the leak speeds up and the tyre gets damaged from running soft. The cheapest outcome is nearly always the early repair.

The simplest route is to leave the car where it is. A mobile fitter can inspect the tyre at your home or work, repair it there if the standard allows, and fit a replacement in the same visit if it doesn't.