Tyres wearing unevenly
One edge gone, the centre bald, or patches worn around the tyre.
Direct causeThe tyre is not presented to the road squarely, or not at the correct pressure, through part or all of its rotation.
Physical realityThe wear pattern is a physical record of the fault, written over thousands of kilometres. Rubber disappears where load and slip concentrate, so the shape of the wear identifies the cause more reliably than any single measurement taken on a ramp.
Safety riskMedium to high, and easy to miss. Tread at a worn edge can be below the legal minimum while the centre of the same tyre still looks serviceable. In South Africa the minimum is 1.6 mm, and it applies across the tread, not on average.
Required fixRead the pattern, inspect the joints and bushes, then align. Fitting tyres without correcting the cause consumes the new set exactly the same way.
What usually causes it
- Both edges worn, centre good — chronic underinflation — the tyre is riding on its shoulders.
- Centre worn, edges good — chronic overinflation — the contact patch has narrowed to a strip.
- One edge only, smooth — camber out of specification, or a bent or worn component holding the wheel at an angle.
- Feathered across the tread blocks — toe out of specification. Run a hand across the tread: sharp one way and smooth the other is toe, every time.
- Cupped or scalloped in patches — the wheel is bouncing rather than tracking — worn shock absorbers, or a wheel out of balance.
Diagnostic verification criteria
How a workshop separates these causes rather than replacing parts in sequence.
- Primary indicator: The pattern itself, before any measurement. Feathering is toe, a single smooth edge is camber, scalloping is damping. The alignment machine then confirms it in numbers.
- Tolerance limit: 1.6 mm minimum tread depth in South Africa, measured at the worst point on the tyre rather than an average across it.
- Secondary failure risk: An alignment carried out without first checking bushes and ball joints sets the geometry against worn parts. It reads correct on the ramp and moves again the moment the car is loaded and driven.
RM Steering and Suspension reads wear patterns and corrects the cause in Brackenfell, Cape Town — geometry and worn components together.
Request a suspension inspection