Why an outside plug alone is not the standard
A plug pushed in from outside, without removing the tire, is quick and is often used to get home. Common industry guidance treats it as temporary, for three reasons:
- Nobody has looked inside the tire to check for hidden damage.
- A plug alone fills the hole but does not seal the inner liner the way a patch does.
- The direction and path of the puncture have not been checked.
The repair generally recommended is a combined patch and plug, fitted from inside after the tire is removed and inspected. The plug fills the injury, and the patch seals the inner liner.
If a tire has been plugged at the roadside, have it inspected properly afterwards.
What not to do
- Do not keep driving on a flat. Pull over somewhere safe as soon as you can. A few miles on a flat can turn a repairable tire into scrap.
- Do not rely on sealant long term. Aerosol and liquid sealants can get you to a shop. They can also make an inspection and repair harder, and some can affect pressure sensors. Tell the shop if you used one.
- Do not ignore a slow leak. A tire that needs air every week usually has a puncture or a problem at the bead or valve. Finding it early keeps it repairable. The article on checking tire pressure covers how to spot it.
Repair or replace: a quick guide
| Situation | Likely outcome |
|---|---|
| Small nail or screw in the central tread, not driven flat | Generally repairable after inspection |
| Puncture in the shoulder | Usually replace |
| Any sidewall cut, puncture or bulge | Replace |
| Large hole, cut or tear | Usually replace |
| Driven any distance flat | Inspection decides, often replace |
| Previous repairs close to the new damage | Inspection decides |
The shop's inspection is the final word in every case.
What to do the moment a tire goes flat
The first few minutes decide whether the tire can be saved, and more importantly whether you stay safe.
- Ease off and signal. Do not brake hard. Let the vehicle slow and steer gently toward a safe place.
- Get fully off the road. A wide shoulder, a parking lot or a side street. If the only choice is a narrow shoulder on a busy road, drive slowly to somewhere better; a damaged tire is cheaper than a collision.
- Hazard lights on. If you have warning triangles, set them out behind the vehicle.
- Decide whether to change it yourself. Only on firm, level ground well away from traffic, with the parking brake set. If any of that is missing, call for help.
- Leave the object in. If you can see a nail or screw, do not pull it out. It is often partly sealing the hole, and the shop wants to see it.
Once the spare is on, check its pressure as soon as you can. Compact spares have a speed and distance limit printed on them, so treat them as a way to reach a shop rather than a replacement.
Matching when a tire cannot be saved
If a tire must be replaced, matching it to the others matters. On all-wheel-drive vehicles in particular, a new tire next to worn ones can create a difference in diameter that the drivetrain does not like. Ask whether one tire is acceptable or whether a pair is wiser. The light truck tires and passenger tires pages cover choosing a replacement.
Getting it looked at
Visit a Purcell location that carries tires for your vehicle and ask them to inspect the damage. The car, SUV and light truck service page lists what Purcell's consumer-facing locations offer. Ask the store whether it handles puncture repair for your tire before you go.