Flat Tire Repair with an Inside Patch and Plug

Slow down, get off the road somewhere safe, and stop driving on the tire. A tire driven even a short distance with little air can tear up its inside and turn a simple repair into a replacement. Put on the spare or use your inflator kit if it is safe, then bring the car in or call (909) 608-7699.

If you have a spare

Mount it, check its pressure, and respect its limits. A compact spare carries its own printed limits on the sidewall, commonly a 50 mph ceiling and an inflation pressure around 60 psi, both far from what your regular tires use. See spare tire service for what the label on your spare means.

If you have an inflator kit

Many newer cars come with a sealant and compressor instead of a spare. Sealant can get you to the shop, but tell us it was used. It coats the inside of the tire and the TPMS sensor, and the sensor may need cleaning or replacement.

If the tire is losing air slowly

Add air to the placard pressure and drive straight in. Do not wait for the tire to go fully flat.

Tire industry repair standards allow a repair when the puncture sits in the central tread crown, measures 1/4 inch (6 mm) or less, and does not overlap an earlier repair. The tire must also have enough tread left and no hidden damage inside. We check all of that before quoting a repair.

Some run-flat tire makers limit or prohibit repairs. Some performance tire makers also note that a repair can affect the speed rating. We check your tire's guidance. Our patch versus replace guide goes deeper into the decision.

The tire comes off the wheel so we can see the inner liner. We remove the object, clean and prepare the hole, and pull a combination patch and plug through from the inside. The plug fills the path the nail made, and the patch seals the liner. Then the tire is remounted, inflated, leak-tested and balanced.

Step by step:

1. Mark the tire and wheel position, then dismount.
2. Inspect the inner liner for rubbing, wrinkles or crumbs of rubber, signs it was driven low.
3. Remove the object and check the angle of the puncture.
4. Prepare the hole and the liner surface.
5. Install the patch-plug from the inside and seal it.
6. Remount, inflate to spec and check for leaks.
7. Rebalance, reinstall and torque the lug nuts.
8. Check the TPMS reading.

This takes longer than a quick plug from the outside, and that is the point. The inside view is what tells us the tire is safe.

An outside plug only fills the hole. Nobody looks at the inside of the tire, so damage from driving it low stays hidden, and moisture can reach the steel belts through the puncture path. Plug-only repairs are a roadside stopgap, not a finished repair. We will not sign off on one as permanent.

If you already have an outside plug from a roadside kit, bring the tire in. We can remove it and do the job properly if the tire still qualifies, or show you why it does not.

What a plug-only repair misses

• Inner liner damage from low-pressure driving
• A puncture path at an angle that weakens the belts
• A second object you did not see
• A sensor damaged by the object or by sealant

Not every flat comes from a puncture. Air can escape at the bead where the tire meets the wheel, through a cracked valve stem, past a loose valve core, or through a hairline crack in a wheel. We find it by inflating the tire and checking with soapy water, which bubbles right at the leak.

Common slow-leak sources:

• Bead leaks: corrosion on aluminum wheels breaks the seal. Cleaning the bead seat fixes most of these.
• Valve stems: rubber stems crack with heat and age, which is why they are replaced with each new tire. See valve stem replacement.
• Valve cores: a loose or dirty core lets air seep out.
• Wheel damage: a pothole can bend or crack a rim.
• TPMS sensor seals: the grommet on a sensor can harden over time.

Each has a different fix, and we show you the bubbles before you approve one. Worth knowing before you chase one: a healthy tire still loses about 1 psi a month on its own, and about another 1 psi for every 10 degrees the weather cools. A tire that drops several psi in a week is a leak. A tire that drops one over a month is normal.

A repaired tire is balanced, set to pressure and checked for leaks before it goes back on. We confirm the TPMS reading and, if the tire lost a lot of air, reset or relearn the warning. We also look at the other three tires, since what you ran over often leaves more than one souvenir.

Before you leave:

• Pressure is set on all four tires, plus the spare if you ask
• The spare goes back in its place, checked for air
• Lugs are torqued to spec
• You get a note on the invoice showing where the repair is

Keep an eye on the repaired tire's pressure for the next few days. If it drops, bring it back and we recheck it. On an AWD vehicle, a repair is often better than replacing one tire, because a single new tire can put the set outside the tread depth spread your drivetrain allows, often only a couple of 32nds of an inch.

NHTSA's tire safety page (opens in a new tab) has more on inflation and everyday tire care.

We show you the damage and explain why, with a photo when it helps. Then we quote a replacement that matches the other tires in size, load index, speed rating and, on AWD vehicles, tread depth. If the other tires are close to worn out, we say so, and you decide between one, two or four.

• One tire: works when the others are fairly new, and on AWD when the tread depth is close.
• A pair: common on front or rear drive cars when the other axle is worn.
• Four: often best when the set is older or on AWD with worn tires.

Check new tires and brands for how we match a replacement, or call (909) 608-7699 with your tire size.

No. Leave the nail or screw where it is. It is often sealing part of the hole, and pulling it can turn a slow leak into a flat on the spot. Check the pressure, add air if you can, and have the tire looked at soon, before the leak lets it run low.

What to do, in order:

1. Take a photo of where the nail sits in the tread.
2. Check the pressure cold, before driving or at least 3 hours after parking, and fill it to the door placard number.
3. Check it again the next morning. Losing a psi overnight is close to normal. Losing several means the tire is going down fast, so switch to the spare.
4. Send a request or call (909) 608-7699 so we can look at it.
5. Skip long freeway runs on that tire until it has been inspected.

A tire that goes soft and is driven even a short distance can be damaged inside, where you cannot see it. The inner liner rubs and leaves a gray, powdery ring. That hidden damage is why some tires with a small nail still cannot be repaired. Pulling onto a side street to deal with it is always better than stopping in a live freeway lane.

A repair only makes sense if the tire is sound on the inside, so the tire comes off the wheel before anything is decided. From the outside, a nail hole can look minor while the liner is already worn from driving low. These are the checks we make, and each one can change the answer.

You see what we found, with photos when they help, before we patch or quote a replacement. A cracked sensor is handled through TPMS service, and a tire that cannot be saved gets a written quote for a matching replacement.