Nail in a tire: can it be repaired or not?

A nail in the tread, the flat part that touches the road, making a hole no larger than a quarter of an inch, is almost always repairable. A nail in the sidewall or in the shoulder, the curved corner between the two, is never repairable by anyone, and the tire has to be replaced.

That is the whole answer. The rest of this page is how to work out which of the two you have, and what a real repair involves so you can tell it from a bad one.

Find where the nail actually is

Crouch down and look at the tire straight on.

The tread is the ribbed band across the middle. If the nail head is anywhere in that band, including between the grooves, you are in the repairable zone.

The shoulder is where the tread curves away toward the wheel. It looks like tread but it flexes like a sidewall, and that is why it is excluded. If the nail is in the outermost rib or past it, treat it as not repairable until a technician says otherwise.

The sidewall is the smooth face with the lettering on it. Nothing there is repairable.

If the nail is right on the boundary, do not guess in your own favour. Measure it if you can, and let the inspection decide.

The repair rules, and where they come from

These are not our rules. The US Tire Manufacturers Association publishes them and any shop worth using follows them:

• The damage must be in the tread area only.
• The hole must be no larger than a quarter of an inch, roughly 6mm. A framing nail qualifies. A screwdriver-sized gash does not.
• The tire must come off the wheel so the inside can be inspected. Damage that looks trivial from outside is often much worse against the inner liner.
• A correct repair is a plug filling the hole and a patch sealing the inner liner, usually as one combined unit.

That last point matters more than the rest. A plug pushed in from outside without taking the tire off is not a repair. It seals the hole without anyone ever looking at the damage inside, and it leaves the steel belts exposed to moisture. We will not do it, and you should not accept it from anyone else.

Things that turn a repairable nail into a replacement

• Driving on it flat. A tire run without air chafes itself apart internally in a few hundred yards. This is the commonest way a cheap repair becomes an expensive tire.
• Repairs too close together, or overlapping an old one. Not permitted, and a tire with several already is at the end of its life.
• Worn-out tread. Repairing a nearly finished tire buys very little. See when to replace tires.
• A run-flat. Repairable far less often and under stricter conditions. Tell us when you book. See EV and run-flat tires.

Should you pull the nail out?

No. Leave it where it is.

While the nail is in place it partly plugs the hole, so the tire often holds enough pressure to stay on the rim. Pulling it out in your driveway turns a slow leak into a flat and tells you nothing, because the decision is made on the inside of the tire.

If the tire still has air, check the pressure against the door placard, top it up, and book. If it is already flat, do not drive on it. Read flat tire in the driveway.

What happens on the visit

We take the wheel off, break the tire down off the rim, and look at the inner liner. That inspection is the job: it shows whether the nail went straight in, whether it cut a belt, and whether the tire was run underinflated long enough to damage itself.

If it passes, it gets a plug and patch and goes back on, balanced and torqued. If it fails, we tell you why and fit a tire we have supplied. We do not fit tires bought elsewhere, and we do not do alignment, rotation alone or balancing alone.

The inspection comes before any sale. Repair versus replace a tire has the full reasoning, and mobile tire replacement cost sets expectations if it goes that way.

Questions people ask

• There is a nail in my tire but it is not losing air. Do I still need it looked at? Yes. A seated nail can hold pressure for weeks and then let go at speed. It is also the cheapest moment to fix it, because the tire is still undamaged.
• How big a hole can be repaired? No larger than a quarter of an inch, about 6mm, and only in the tread area. That limit comes from the US Tire Manufacturers Association and it is not negotiable.
• Is a plug on its own a real repair? No. A correct repair means the tire comes off the wheel, the inside is inspected, and it gets both a plug and a patch. A plug alone does not meet the standard whatever it costs.
• Can a nail in the sidewall be repaired? No. Never, by anyone. The sidewall flexes with every rotation and no patch will stay bonded there. That tire is a replacement.
• I drove a few miles on it before I noticed. Is it ruined? Possibly not, if it kept most of its pressure. If it was flat or nearly flat, expect a replacement. The inner shoulder shows chafing marks that answer it.
• Do I need to replace the other tires at the same time? Usually not for a single puncture. Drivetrain and tread-depth differences can force your hand, which how many tires do I need works through.