If you flip a tire over and look at the wear pattern, you can usually diagnose every alignment, suspension, and inflation issue on the car. Each pattern points to a specific cause. Here are the five most common.
1. Center wear — overinflation
The center of the tread is worn down while the shoulders still have full tread. The cause is consistent overinflation. The center of the tire is bulging out and contacting more road than the shoulders.
Fix: Set pressure to the door-jamb specification. If you've been running 10+ PSI above spec, the tire may already be too worn down the middle to save.
2. Both shoulders wear — underinflation
Both outer and inner shoulders are worn while the center is fine. The cause is consistent underinflation. The tire is flexing into a sag shape and the shoulders are carrying disproportionate load.
Fix: Maintain proper pressure. Underinflation is the most common cause of premature tire wear by far.
3. One shoulder wears — camber off
Just the inner or outer shoulder is worn. The cause is camber alignment out of spec. Negative camber (top of tire leans in) wears the inner shoulder; positive camber wears the outer.
Fix: Four-wheel alignment. Camber problems often come from bent suspension components after a pothole impact — the alignment shop will tell you whether it's an adjustment or a part replacement.
4. Feathering / sawtooth — toe off
Run your hand across the tread. If individual tread blocks feel sharp on one edge and rounded on the other — like a sawtooth pattern — the toe alignment is off. Toe-in or toe-out is dragging the tire sideways as it rolls.
Fix: Alignment. Toe is the most commonly out-of-spec angle and typically the cheapest to correct.
5. Cupping / scalloping — suspension wear
Look at the tread face for wavy patches of high and low wear around the circumference. Cupping means the tire is bouncing as it rolls — usually because the shock absorber or strut on that corner has failed. Sometimes also caused by extreme imbalance over time.
Fix: Replace the shock or strut on the affected corner. The tire may need replacement too if cupping is severe — it can't be evened out.
Diagnosing by axle position
Wear patterns also tell you which corner has the problem:
- Both front tires show the same pattern — front-end issue (alignment, shocks, etc.)
- Both rear tires — rear-end issue
- One front tire only — that corner specifically (bent component, separate alignment issue)
- All four similarly — pressure issue affecting the whole car
When to investigate
Check your tread pattern every time you rotate (every 5,000-7,500 miles). Early detection saves tires. A misaligned tire caught at 2,000 miles into the wear cycle is salvageable. The same misalignment caught at 15,000 miles has destroyed the tire.
The tire is the diagnostic tool. Read it.