Nail in Tire or Flat Tire? What to Do Next

The first five minutes

You see the shiny head of a nail in the tread, or the tire pressure light comes on and one corner looks low. Either way, the next few decisions matter more than the nail does.

Here's the order to take them in:

1. Leave the nail where it is. Michelin's tire damage guide is direct about it: do not pull it out yourself.
2. Check the pressure with a gauge. Compare it with the pressure on your door placard, not the number molded on the tire.
3. Look at where the nail is. Tread, or near the edge and sidewall? That decides whether a repair is even possible.
4. Decide how the car gets to a technician. Spare, mobile service or roadside help, rather than driving on a tire that's losing air.

The rest of this guide explains each step.

Why the nail stays in

A nail or screw that went straight in can sit in its own hole and slow the leak. Pull it out in a parking lot and you may turn a slow leak into a flat on the spot.

There's a second reason. The repair can't be done from the outside anyway. USTMA says the tire must be removed from the rim or wheel and inspected for all possible damage, and that an outside-in or on-the-wheel repair should never be done. The technician removes the object with the tire off the wheel, sees the angle it went in at and checks the inner liner. Leaving it in place helps them see what happened.

Holding air, or going flat?

Your gauge reading puts you on one of two paths.

The tire is close to placard pressure. The nail may be sealing for now. That doesn't make it a repair, and it can let go. Have it inspected before driving further on it. If you need the car today, the spare or a mobile visit is the lower-risk way to get there.

The tire is low or flat. Don't keep driving on it. Michelin's repair criteria are blunt on this: a tire qualifies for repair only if it has not been driven on when flat, because even a short distance driven while completely flat can cause internal damage to the sidewall and carcass. Michelin lists any tire that was driven flat among those that need replacement, not repair.

That's the real cost of "just getting home" on a flat: a repairable nail turns into a new tire.

Where the nail is decides whether it can be repaired

The repairable zone is narrow. Under USTMA guidance and Michelin's criteria:

• Tread area only. USTMA considers a repair only when the damage is limited to the tread area.
• 1/4 inch (6 mm) or smaller. A bigger hole means a replacement.
• Not the sidewall or shoulder. Michelin says a nail in the sidewall is never repairable. USTMA rules out repairs where the injury extends into the shoulder or belt edge, or runs at an angle into the shoulder.
• Not over an old repair. USTMA says repairs can't overlap.

Tap where your nail is on the map below to see how the guidance treats that spot.

The same check lives on its own page: can my tire be repaired?

Changing to the spare

If you have a spare and you're somewhere you can work, AAA's steps for changing a tire start well before the jack comes out:

• Get off the road. AAA suggests a parking lot or side street, on solid, level ground that's well lit.
• Secure the car. Park, switch off, set the parking brake and turn on the hazard lights. AAA also suggests wedges at the wheel on the opposite corner from the flat.
• Loosen the lug nuts before you lift. The car's weight holds the wheel still while you break them loose.
• Use the jack point in your owner's manual. AAA says the manual shows where it goes.
• Tighten in a star pattern. Opposite nut next, not the one beside it.

Then mind the spare's limits. A compact "donut" spare is a temporary tire with its speed limit printed on it; AAA's advice is not to drive over 50 mph on one until your regular tire is back on. Our guide to spare tire types covers the full-size, compact and kit options.

On an interstate shoulder, with traffic close, a tire change is a job for roadside assistance or a mobile van, not for you.

No spare in the trunk?

Plenty of newer cars carry a sealant and inflator kit or run-flat tires instead of a spare. AAA has documented how often new vehicles come without one. Look under the trunk floor now, before you need it, so you know which you have.

If you use a sealant kit, tell the technician before they dismount the tire. A kit gets you moving; it isn't the repair the industry guidance describes, so the tire still needs an internal inspection and then a proper repair or a replacement. Run-flat tires have their own repair rules from each tire maker.

A slow leak with no nail in sight

Sometimes the tire keeps dropping a few psi a week and there's nothing in the tread. Michelin notes that pressure loss could also be a leaking valve, valve cap or even the wheel. From the driver's seat, those look exactly like a puncture you can't see.

NHTSA's advice to check pressure monthly with a gauge, cold, is how you catch this early. If one tire keeps reading low, have it inspected. Our guide to the TPMS light explains when the dashboard warning comes on and why it isn't an early warning.

What a proper repair looks like

If the puncture qualifies, the accepted repair is a plug and patch combination fitted from the inside. Michelin requires the combined plug-and-inside-patch type for all repairs, and USTMA calls a plug alone an unacceptable repair. The full breakdown is in tire plug vs patch.

Extreme Tires' tire repair follows that method:

• dismount the tire and inspect it inside
• repair with a combination patch-plug
• rebalance after the repair
• set pressure to your door placard

It's done at the Sunrise shop or from the mobile van, which covers Miami-Dade, Broward and Palm Beach. If the nail is in the shoulder or sidewall, or the tire was driven flat, the van can fit a replacement where you're parked instead. See mobile service or call (954) 773-1896.

If it needs a new tire

When a repair is ruled out, match the replacement to your door placard: size, load index and speed rating. All-wheel-drive cars can be stricter about tread depth differences between tires, and your owner's manual has the rule for yours. Shop by size to see what fits. Tires ship free to the 48 contiguous states and DC, and installation is available in South Florida.

Quick reference

Driving through storm debris? Our blog post on nails in tires after a storm cleanup covers the weeks after a hurricane, when roofing nails are everywhere.