Uneven Tire Wear: Common Causes, Warning Signs and How to Fix It

The wrong tire pressure, a wheel alignment that's out of spec, a wheel that's out of balance or worn suspension parts. The wear pattern tells you which one. Fix the cause first, then rotate or replace the tires, or the new set will wear the same way.

Key Takeaways

• Wear in the centre of the tread points to overinflation; wear on both outer edges points to underinflation, according to the Tire and Rubber Association of Canada (TRAC).
• Transport Canada says uneven tread wear can be caused by improper wheel alignment or a tire imbalance.
• Transport Canada recommends a pressure check at least once a month, on cold tires, and an alignment check once a year.
• Rotating tires about every 10,000 km is common practice, per Transport Canada, because front and rear tires wear differently.
• Replace a tire once the tread is worn down to the tread wear indicator, which Transport Canada puts at 1.5 mm.

Common Causes: Why Tires Wear Unevenly

A tire wears evenly only when it meets the road flat, at the right pressure, pointing straight ahead. Change any of those and some part of the tread works harder than the rest.

Tire Pressure That's Too High or Too Low

Tire pressure is the cheapest cause to fix and the easiest one to overlook. TRAC's guide to tire inflation explains that an overinflated tire lifts at its edges, so the centre of the tread wears faster. An underinflated tire sags at its edges and wears the outside edges instead.

Looks won't tell you. Transport Canada's Riding on Air tire guide warns that a tire can appear fine while being underinflated by as much as 20 per cent.

Wheel Alignment and Tire Imbalance

Wheel alignment sets the angle at which each tire meets the road. Transport Canada says misaligned wheels may drag instead of rolling freely, and that a hard hit on a curb or pothole can knock the front end out of alignment. TRAC adds that poor alignment raises fuel consumption, too.

Balance is a separate job. A wheel that's out of balance can send a pounding or shaking through the steering wheel or your seat, Transport Canada notes.

Worn Suspension Components

Shocks, struts, ball joints and tie rod ends keep each tire planted at the correct angle. When they wear, the tire bounces or shifts under load and the tread scuffs in patches. Here's an illustrated guide to suspension if you want to see how the parts fit together.

Drivetrain and Driving Habits

Front tires do more work. TRAC says they wear from both steering and rolling, so they wear faster than rear tires. Driving an EV? Our guide on why electric vehicle tires wear out more quickly covers what's different.

Diagnosis: Reading Uneven Tire Wear Patterns

Each pattern points to a short list of suspects. Inspect all four tires and note where on the car each one sits.

Michelin Canada links feathering to toe misalignment and cupping to worn shock absorbers, struts or an out-of-balance wheel.

DIY Steps: Check Your Tires at Home

Transport Canada advises inspecting your tires regularly for signs of excessive or uneven wear. You don't need a lift for that, just a gauge, a toonie and 10 minutes.

1. Check the pressure cold. Transport Canada defines cold as parked for at least three hours or driven less than 2 km.
2. Compare it with the label. The tire information label is usually on the edge of the driver's door, the door post, the glove box or the fuel door, not the sidewall.
3. Run your hand across the tread. Feathered blocks feel smooth one way and sharp the other.
4. Try the toonie test. CAA says that if the tread covers more than a quarter of the coin, you're good for now.
5. Look for the wear bars. Transport Canada says most tires have six tread wear indicators spaced around the tire.

A tread depth gauge gives a more exact reading. Here's how to check your tire's tread depth step by step, plus the tire pressure mistakes most drivers make.

Repair Options: How to Fix Uneven Tire Wear

The fix depends on what the pattern told you. Rotating tires that wear unevenly without correcting the cause only spreads the damage to all four corners.

Adjust Pressure, Rotate and Balance

If pressure caused the wear, set every tire to the label and recheck monthly. A tire rotation then evens out what's left of the tread. Balancing corrects a vibration that shows up at highway speed.

Get a Wheel Alignment

If the wear sits on one edge or the blocks are feathered, start with a wheel alignment. Michelin Canada ties one-edge wear to misalignment and recommends an alignment check when you see it. Our explainer on why you should get your alignment checked goes deeper.

Replace Worn Parts and Tires

Cupping points to worn shocks or struts, or an out-of-balance wheel, so those parts get inspected first. Replacement isn't optional once a tire is worn down to the indicator, according to Transport Canada. Shopping for a new set? Start with these tire-buying questions, answered.

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Expected Costs: What Shapes the Bill

Shop rates and parts prices vary by vehicle, province and shop, so ask the technician for a written quote before work starts. What drives the bill is simple, though. A pressure fix costs you a few minutes at an air pump. A rotation, a balance or an alignment is labour on the tires you already own. Suspension parts and a fresh set of tires add parts to that labour, which is why catching the problem early matters.

Waiting has a cost of its own. Transport Canada says one tire underinflated by 56 kPa (8 psi) can raise fuel consumption by 4 per cent. TRAC warns that under- or overinflation can cause premature wear and uneven wear, shortening tire life drastically.

Catch uneven wear early and the fix is usually a gauge and an alignment, not four new tires.

When to Seek Professional Help

Some symptoms need a mechanic and a lift. Book a service appointment if you notice any of these:

• pulling to one side on a straight, flat road
• the steering wheel or seat shakes at highway speed
• one edge of a tire is worn far more than the other
• cupping or bald patches appear on any tire
• handling feels different after a hard pothole or curb hit

Suspension work isn't a driveway job. Here's why you should leave suspension work to the pros.

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Prevention: How to Stop Uneven Tyre Wear Before It Starts

Whether you spell it uneven tyre wear or tire wear, the way to prevent uneven tire wear is a routine, not a repair.

• Check pressure at least once a month; Transport Canada says tires lose about 7 kPa (1 psi) for every 5°C drop in temperature.
• Rotate about every 10,000 km, or follow the interval in your owner's manual.
• Have the alignment checked once a year; TRAC's tire care checklist also cites every 25,000 km.
• Slow down for potholes and keep clear of curbs.
• Recheck pressure and inspect the tread every time you swap to or from winter tires.

A hard pothole hit can knock the alignment out. This pothole survival guide helps you dodge the worst of it.

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Four tires wearing the same way is the sign of a healthy car.