What do uneven tyre wear patterns mean?

Four wear patterns, what each one is telling you about pressure or geometry, and which two you can fix yourself with a gauge.

Difficulty: beginner
Time: 10 min
Read: 3 min

Short answer

Worn in the middle means over-inflated. Worn on both shoulders means under-inflated. Worn on one side only, or a sawtooth edge you can feel with your hand, is a wheel alignment or suspension geometry problem that a garage has to correct.

A tyre records how the car has been treated. Reading that record takes about a minute per wheel and it identifies problems that would otherwise cost you a set of tyres every year.

What each tyre wear pattern is telling you

Step by step

Look at the tread across its full width.Compare the depth in the outer grooves with the depth in the middle. A visible step between them is the pattern you are reading.
Diagnose a worn centre as over-inflation.Too much pressure bows the tread outwards so only the middle band carries the load. The fix is your pressure gauge and the placard figures.
Diagnose worn shoulders as under-inflation.Too little pressure lets the tread collapse in the middle so the two shoulders take everything. Again, this is a gauge job, not a garage job.
Treat one-sided wear as geometry.Inner or outer shoulder gone while the rest is healthy means the wheel is not pointing where it should. No pressure adjustment will help. Alignment is a cheap check and a cheap correction.
Feel for feathering with your palm.Run your hand flat across the tread in both directions. If it is smooth one way and sharp-edged the other, the toe setting is out — another alignment job.
Look for cupping or scalloping.Regular dips around the circumference usually mean a worn shock absorber letting the wheel bounce. That is suspension work and belongs with a garage.
Check whether it is one wheel or a pattern.Both fronts wearing on the inner edges is normal geometry drift. One wheel alone is more likely a knock from a kerb or a pothole.
Fix the cause before fitting new tyres.New rubber on an uncorrected alignment fault wears out exactly the same way, usually within a year. Alignment first, tyres second.

Tips

Photograph the wear when you spot it, so you can show a garage rather than describe it.
Have the alignment checked after any hard pothole strike, whatever the tyre looks like.
Rotating tyres front to back spreads wear but does not correct a geometry fault — it just moves it around.

Common mistakes

Replacing tyres without checking why they wore out — Alignment faults are cheap to correct and expensive to ignore. Fitting a new set on a car that eats inner shoulders simply buys another set of ruined tyres.
Assuming all uneven wear is pressure — Only centre and shoulder wear are pressure. One-sided wear, feathering and cupping are all mechanical and cannot be corrected with air.

If it doesn't work

Both front inner edges worn

Cause: Toe or camber out of specification — Fix: Four-wheel alignment check at a specialist, then replace the tyres.

Sharp edges you can feel across the tread

Cause: Incorrect toe setting — Fix: Alignment correction. The noise it also causes usually disappears with it.

Regular dips around the tyre

Cause: Worn dampers letting the wheel bounce — Fix: Have the suspension inspected by a garage — this is not owner-level work.

Wear pattern returns after alignment

Cause: A worn bush or arm rather than a setting — Fix: Ask the garage to check the suspension components, not just reset the geometry.

Questions people ask

Can I fix uneven wear myself?

Only the two pressure-related patterns — worn centre and worn shoulders. Everything else is alignment or suspension and needs a garage with the right equipment.

How often should alignment be checked?

Whenever tyres are replaced, after any significant pothole or kerb strike, and any time the car pulls to one side or the steering wheel is off centre on a straight road.

Is a tyre with uneven wear still legal?

Only if it still has at least 1.6mm across the central three quarters and around the whole circumference. One-sided wear frequently fails that test while the rest of the tread still looks respectable.