Uneven tire wear: what the pattern says about the car

Why it matters

Proper alignment keeps the car tracking straight and wears the tires evenly, and the suspension keeps the tires in contact with the road. When something in that chain is off, the tread shows it.

A misaligned car quietly eats through tires faster than they should wear, and worn bushings, ball joints and tie rod ends can all cause uneven wear. On a used car, the wear pattern tells you what the steering and suspension have been doing.

Common causes

• Wheel alignment, when the wear is on the inner or outer edge, or differs between the left and right sides
• Running overinflated for a long time, when the wear is down the center
• Running underinflated, which makes tires wear unevenly
• Worn shocks, struts or dampers, when the wear is cupped or feathered
• A worn ball joint
• Worn control arm bushings or tie rod ends, which can allow slight misalignment
• Suspension work done without a wheel alignment afterward
• On an electric car, the extra weight and instant torque, which make tires wear faster and less evenly

Step by step

1. Look across the full width of each tire, and compare all four, left side against right.
2. Check the tread depth at three points across each tire. Wear is rarely even, and the lowest reading is the one that counts.
3. Run a hand across the tread blocks. Small steps you can feel are feathering.
4. Check the pressure on cold tires against the sticker in the driver's door jamb, not the number on the sidewall.
5. Read the sidewalls: the same size on all four, no cuts, bulges or cracks.
6. If the car has had suspension work, ask whether the alignment was checked afterward.
7. Mention the wear pattern at the next service or the pre-purchase inspection, together with any pull, vibration or clunk you noticed.

What the tire wear pattern tells you

• Wear on the inner or outer edge: alignment, not the tire.
• Different wear between the left and right sides: often a wheel alignment issue rather than the tires themselves.
• Wear down the center of the tread: typical of running overinflated for a long time.
• Cupped wear: can point to alignment, worn shocks or struts, or a ball joint.
• Feathering, felt by hand as small steps across the blocks: points to worn dampers.
• One tire wearing noticeably faster than the rest: usually pressure or suspension.
• Different sizes on the sidewalls: something was changed without thought.
• Fine cracks in the sidewall rubber: the tire is dry and old, even with tread left.

What people get wrong

Assuming uneven wear or a pulling car is always an alignment problem. Tire pressure, tire condition and suspension wear can all cause the same symptom, and worn tie rod ends cause a wandering feeling that alignment alone won't fix.

When to get it checked

Checking the pressure and the wear pattern is reasonable to do yourself, but wheel alignment and ball joint, control arm, bushing or tie rod work belong to a professional. If uneven wear comes with a clunk when turning and looseness in the steering, have it inspected right away: a ball joint failure while driving can cause a sudden loss of steering control.

Read next

• Car pulls to one side: how to find the cause
• Clunking noise over bumps: what is worn
• Tire pressure light: a puncture, or just the cold?

This page is general information and does not replace a professional assessment. Symbols, codes and behaviour vary between makes. Always check the handbook for your own car.