Q: I just returned from my nearby gas and repair station after having a leaking tire repaired. The fellow made a surprisingly quick repair, and it seems to work fine. My son told me they plugged the hole in the tire, and he thought this wasn’t a good thing. How else should it be fixed? I want to be sure the tire remains safe and doesn’t lose air.

— Susan Turner

A: Good question, Susan. Tire repair is serious business, and a large percentage of tire repairs made aren’t up to industry standards. As a general rule, a tire may be repaired if it has legally adequate tread remaining; if there’s no structural damage from the puncturing object or from the tire being operated while underinflated; and if the puncture is located between the outer two tread grooves and is less than a quarter-inch in diameter. Repairs to a tire’s shoulder or sidewall are off-limits, as this area is subjected to constant flexing, which may cause the repair to fail.

Proper tire repair consists of three important steps: The tire should be removed from the wheel for inspection of the casing, the puncture is filled, and the tire’s inner liner patched. Outside-in repairs, such as a non-vulcanizing string plug, should not be considered a permanent fix, as an internal inspection was not performed, and this repair method has a mediocre success rate. Aerosol inflator and sealer products are a good companion to your break-down/emergency kit, but should only be utilized as a limp-home method. When using an inflator/sealer, be sure it’s nonflammable — a rusty older can may not be — and advise the person subsequently repairing the tire that such a product was used. Finally, never have a tube installed within a tubeless tire as a means of repair.

The right way to repair a tire is to demount it from the rim, inspect the casing for damage, and perform an appropriate repair from the inside. Pinhole punctures, which visually close up once the nail is removed, can be patched, and larger circular punctures should be reamed, plugged and patched. Tears or slices should not be repaired as they can grow in length.

Reaming the puncture cleans the opening, makes room for the plug, and lessens the chance of it being cut by a steel belt’s strands. A rubber plug, coated with vulcanizing cement, is then forced through the puncture, filling it, and after adequate cure time is cut off flush with the inner liner. Finally, the liner is cleaned, buffed, and patched. Mushroom-shaped combination plug-patches are an alternative to the above method, lessening the chance of procedural errors and saving time.