Repair or replace? What actually decides it

The three rules

In the tread, not the shoulder or the sidewall. Under 6mm across. And the tyre has not been driven flat.

All three must be true. Fail any one and the tyre cannot be safely repaired, and no amount of wanting it to be changes that.

About seven in ten punctures we see pass all three. The other three are replacements, and we say so before we start.

Why nobody repairs a sidewall

The sidewall flexes every single revolution and it is the structural part of the tyre. A patch there does not fail gradually, it fails suddenly.

If a repairer offers to do one, that tells you everything you need to know about the rest of their work.

Driven flat is the one people hide

A tyre run flat for even a short distance is usually destroyed on the inside, where the liner has been chewed up by the rim. From the outside it can look perfect.

So tell whoever is repairing it. It is not a telling-off — it is the difference between a repair that holds and one that lets go at speed.

Strings, plugs and what a proper repair is

A string pushed into the tread from the outside, with the tyre still on the vehicle, takes four minutes and is not a permanent repair by any recognised standard. It is a get-you-home fix.

A proper repair means the tyre comes off the rim, the damage is inspected from the inside, and a combined plug-and-patch is fitted and the wheel rebalanced.

The arithmetic

A repair is £35. A tyre is £58 to £184. Anyone telling you a repairable puncture needs a new tyre is making a choice about your money.

The reverse is also true: a repair on a tyre that fails the three rules is cheap right up until it is not.

Run-flats are a different conversation

The entire point of a run-flat is that you can keep driving on it deflated, which means the one thing that rules out a repair has usually already happened by the time you notice.

Some manufacturers permit repair within strict limits; others forbid it entirely. The honest position is that it depends on the tyre and on how far it was driven, and anybody giving you a blanket answer either way is guessing.

We will inspect it and tell you which case yours is, rather than deciding in advance.

A run-flat that has actually been run flat is finished. The difficulty is that you may not have realised it was.

How many repairs is too many

There is no legal limit, but there is a practical one. Repairs must not overlap and must not sit too close together, and a tyre with several is a tyre that has had a hard life.

Two well-separated repairs in the tread on an otherwise sound tyre is normal and safe. Four is a tyre telling you something about where you park.

We will say when we think a tyre has had enough, and we will say it before taking payment for another repair.