Puncture Repair: When It's Safe and When You Need a New Tyre

Puncture repair is one of the most misunderstood parts of tyre work. Some garages will refuse to repair almost anything and sell you a new tyre. A reputable fitter follows British Standard BS AU 159 — the legal framework that defines exactly which punctures are safe to repair.

What is BS AU 159?

BS AU 159 is the British Standard for the permanent repair of car and light van tyres. A repair that doesn't meet this standard is not legally safe to fit and you may be uninsured if you have an accident.

The repairable zone

A repair is only permitted in the central three-quarters of the tread — the 'minor repair area'. Sidewall damage and shoulder damage cannot be repaired safely, ever.

Repair limits

• Puncture diameter: up to 6mm in passenger car tyres.
• Only the central 75% of the tread is repairable.
• Sidewall damage: never repairable.
• Run-flat tyres driven on while flat: usually not repairable.
• Tyres with cord damage or internal separation: not repairable.
• Tyres with tread below 1.6mm: replace, don't repair.

How a proper repair is done

A correct repair is from the inside of the tyre. The tyre is removed from the rim, the inside inspected for hidden damage, the puncture cleaned, and a combined plug-and-patch (mushroom plug) is fitted from the inside out. External 'string' plugs alone are not a permanent repair and don't meet BS AU 159.

When to choose repair over replacement

If the damage is in the repairable zone, the tyre is otherwise in good condition, and tread is above 3mm, repair is almost always the right choice. A good repair lasts the life of the tyre and costs around a third of a new fit.

When you need a new tyre

Sidewall damage, bulges, multiple punctures within 16mm of each other, or any damage on a tyre that's already worn — these all mean replacement. We'll tell you straight.

Not sure which yours is? Call 0330 043 5521 and we'll inspect honestly. If it's repairable we'll repair it for a fraction of a new tyre.