Uneven tyre wear is evidence, not a diagnosis by itself. The pattern can point toward inflation, alignment, balance, suspension, rotation or driving conditions, but a workshop should inspect the vehicle before promising one cause.
Wear on both shoulders
When both outer edges wear faster than the centre, underinflation is one possible cause. Michelin explains that insufficient pressure shifts more load toward the shoulders and can increase flex and heat.
Check cold pressure against the vehicle placard, inspect for air loss, confirm load and review the customer’s pressure-maintenance history.
Wear in the centre
Excessive centre wear can indicate overinflation because the centre of the contact patch carries more of the load. Do not set pressure based on the maximum number moulded on the sidewall. Use the vehicle manufacturer’s recommended cold pressure unless a qualified requirement says otherwise.
Inner-edge or outer-edge wear
Strong wear on one shoulder may be associated with camber, toe, alignment or worn suspension components. Michelin advises professional geometry diagnosis, while Bridgestone’s guide identifies one-sided shoulder wear as a common irregular-wear condition related to excessive positive or negative camber.
Feathering or heel-and-toe wear
Feathering feels smooth in one direction and sharp in the other across tread ribs. Heel-and-toe wear creates a saw-tooth feel around tread blocks. Alignment settings, vehicle design, rotation history and operating conditions can contribute. Record the position and direction of the pattern before rotating or replacing the tyre.
Cupping or scalloped wear
Cupping appears as repeated high and low patches around the tyre. Bridgestone lists alignment, worn suspension or steering components, imbalance, pressure and missed rotation among possible contributors. Correcting the cause will not restore rubber already worn away.
Patchy wear, vibration or rapid loss
Inspect the tyre and wheel for impact damage, separation, foreign objects, poor repair, mounting problems and balance. If there is a bulge, exposed cord, structural damage or sudden pressure loss, stop treating the issue as a routine alignment sale and follow safe inspection procedures.
A workshop inspection record
- Vehicle, mileage, tyre size and wheel position.
- Cold pressure and vehicle placard pressure.
- Inner, centre and outer tread-depth readings.
- Photographs of the pattern and visible damage.
- Alignment, balance, suspension and rotation observations.
- Recommendation, customer approval and completed action.
Do not sell an alignment because the tyre looks uneven. Use the wear pattern to begin a proper diagnosis.
For fleet operators, consistent tyre records make recurring wear and replacement leakage easier to see. Learn about Tyrestore passenger-car fleet tyre management.