When to Replace Your Tires

Tires are a wear item with a real end-of-life point, and driving past it is one of the few maintenance decisions that has an immediate, direct effect on stopping distance and control. Here is how to know when a tire is done, rather than guessing.

Check Tread Depth — the Real Number, Not the Legal Minimum

The legal minimum tread depth in Alberta is 1.6mm. That number tells you when a tire is illegal, not when it is unsafe. Wet and winter traction fall off well before a tire reaches that point.

  • 4mm or less: time to start planning replacement, especially heading into winter.
  • 2mm or less: braking distance and hydroplaning resistance are both meaningfully worse than a new tire. Replace it.
  • The toonie test: insert a toonie into the tread groove with the bear’s paws pointing down. If you can see the top of the paws, tread is getting low. If you can see the rim of the coin clearly above the paws, it is time to replace.

Sidewall and Surface Damage

Tread depth is not the only failure point. Any of the following means the tire needs to be looked at regardless of remaining tread:

  • Bulges or bubbles in the sidewall — this is a structural failure risk, not a cosmetic issue, and it can fail suddenly at speed.
  • Sidewall cracking (dry rot), common on tires that are old but low-mileage.
  • Punctures in the shoulder or sidewall, which usually cannot be safely patched the way a tread-area puncture can.
  • Uneven wear across the tread face, which is often a symptom of an alignment or suspension issue, not a tire defect — the tire may need replacing, but the underlying cause needs fixing too or the new tire wears the same way.

Tire Age Matters Even With Good Tread

Rubber degrades with age regardless of how many kilometres are on the tire. A tire built more than six years ago should be inspected closely even if the tread looks fine, and most manufacturers recommend replacement by ten years regardless of appearance. The manufacture date is stamped on the sidewall as a four-digit DOT code — the first two digits are the week, the last two are the year.

Why Uneven Wear Is a Diagnostic Clue, Not Just a Tire Problem

If one tire is wearing faster than the others, or wearing unevenly across its own face, do not just replace that tire and move on. Wear patterns tell a story: wear concentrated on the inside or outside edge usually points to an alignment issue, cupping usually points to a suspension component, and wear on just one tire versus its pair often points to a rotation that was skipped. Replacing the tire without addressing the cause means the new tire wears the same way. A wheel alignment is recommended once per year and/or when replacing tires.

Frequently Asked Questions

How much tread depth do I need before winter? At minimum 4mm going into the winter season. Below that, traction on snow and ice, and stopping distance, drops sharply .

Can I replace just one tire, or do I need to do all four? It depends on the remaining tread depth and wear pattern on the other three. If they are close in tread depth, one tire can usually be matched. If there is a significant gap, mismatched tread depth on the same axle can affect handling and, on all-wheel-drive vehicles, can stress the drivetrain. We check this before recommending a partial replacement.

Do you check for alignment issues when I bring a car in for tires? Yes. Uneven wear patterns are one of the first things we look at, because replacing tires without correcting the underlying alignment or suspension issue just repeats the same wear on the new set.

Auto Imports carries a range of tire brands and rims and can advise on the right fit for your vehicle and driving needs. Call (780) 431-2828 or book online at auto-imports.ca.