Wear concentrated on one edge of a tyre, the inner or the outer shoulder, has a clear and consistent meaning: the wheel is not sitting square to the road. It is the classic signature of an alignment or camber fault, and it is one of the most common wear problems a fitter sees.
Inner edge wear
Wear on the inner shoulder is the more common, and the more easily missed, because that edge faces in and is hard to see without turning the wheel. Its usual causes:
- Negative camber: the top of the wheel leaning in
- A toe setting that scrubs the inner edge
- Worn suspension parts letting the geometry drift
- Often triggered by a kerb or pothole impact
Because it hides, inner-edge wear frequently goes unnoticed until the tyre is badly worn, or until an MOT picks it up.
Outer edge wear
Wear on the outer shoulder points the other way:
- Positive camber: the top of the wheel leaning out
- A toe-in setting
- Hard, frequent cornering, which loads the outer edge
- Sometimes chronic under-inflation combined with alignment
Outer wear is easier to spot on a routine glance, but no less worth chasing.
Why it happens
In both cases the tyre is being dragged slightly sideways as it rolls, scrubbing one shoulder away faster than the rest. Alignment settings that are out by a small amount, or suspension that has worn or been knocked out of place, are almost always behind it. A pothole or kerb strike is a frequent starting point, covered in how alignment faults damage tyres.
Putting it right
The fix is a wheel alignment check, which measures the camber and toe and corrects them, plus repair of any worn suspension part that threw the geometry out. The signs a car needs alignment, pulling, an off-centre wheel, this very wear, are the prompt to book it. The worn tyre itself may need replacing if that edge has reached the legal limit, but the alignment must be corrected first, or the replacement wears the same way.
From the workshop: inner-edge wear is the sneaky one. The outside of the tyre looks fine, plenty of tread, and the inside's down to the cords where you can't see it. I always run a hand round the inner shoulder. Nine times out of ten this is tracking, and a kerb or a pothole started it.
Sources and accuracy. This reflects standard edge-wear diagnosis at the time of writing; an alignment check confirms the exact cause. If anything here looks wrong, get in touch and we will check it and put it right.
Common questions
What causes inner edge tyre wear?+
Usually alignment, negative camber or a toe setting that scrubs the inner shoulder, often after a kerb or pothole impact or from worn suspension parts. The inside edge is hard to see, so this wear frequently goes unnoticed until the tyre is badly worn or fails an MOT.
What causes outer edge tyre wear?+
Positive camber or toe-in, and sometimes hard, frequent cornering. Chronic under-inflation can pull wear toward the edges too, so very worn outer shoulders may be alignment and pressure combined. A wheel alignment check identifies which.
Is one-edge tyre wear an alignment problem?+
Almost always. Wear isolated to one edge, inner or outer, is the classic signature of an alignment or camber fault, as opposed to both edges (under-inflation) or the centre (over-inflation). An alignment check is the right next step.
How do I fix edge wear on a tyre?+
Have the wheel alignment checked and corrected, and any worn suspension parts that threw it out repaired. Fixing the alignment stops further edge wear; the worn tyre itself may need replacing if it is down to the legal limit on that edge.