A punctured tire is never a joyous occasion, but if it can be repaired, the hassle and expense are often minimal. Some factors are beyond a driver's control, however there are steps that you can take to maximize the chances that a flat can be repaired.
Aside from blowouts and large gashes in the tire that are obviously not repairable, there are three main factors that determine if a tire can be fixed:
- The size of the puncture.
- The location of the puncture.
- Whether the tire was driven on while flat.
With regard to size, if the puncture is 1/4" diameter or smaller, it may be repairable. If the hole is larger than 1/4", replacement is required.
As far as location is concerned, punctures in the tread area of the tire are often repairable. Punctures in the sidewall or shoulder of the tire are not. While it may be physically possible to plug the hole, the flexing of the sidewall is likely to work the repair loose.
Driving on the flat tire is the biggest item under the driver's control. Driving even a short distance on a tire that has lost pressure can leave it unfit for future service, even if the actual puncture is perfectly repairable. Damage to the sidewall from running without air pressure makes the tire unsafe for future use. For detailed information on repairable and non-repairable punctures, read "Flat Tire Repairs - Past the Point of No Return."
If you hope to save the tire, stop immediately when you have a flat as long as it's safe to do so. If the tire looks like it can be repaired, change to the spare, make a temporary repair to re-inflate the tire or have the car towed to a service location. Then make sure to have the tire properly repaired with both a patch and plug.