How to Tell If Your Winter Tires Are Still Good

Five minutes in the driveway before changeover season saves you from paying to mount a set that should be replaced, and from driving on tires that no longer do the job.

Work through these in order.

1. Tread depth, with a quarter

Take a Canadian quarter and push it into the tread groove with the caribou's nose pointing down.

• Tread reaches the nose or below: roughly 4/32 left. That is the winter replacement point. Snow traction has already dropped off noticeably.
• Tread covers past the nose: you still have usable winter depth.

Check in at least three places across the width of each tire and on all four. If the outer edges are down and the middle is fine, you have been running them underinflated or you have an alignment problem. If the middle is down and the edges are fine, they have been overinflated.

Either pattern is worth sorting before you buy the next set, or you will wear that one out the same way.

2. The date code

On the sidewall, find "DOT" followed by a string of characters. The last four digits are the manufacture date: week, then year.

"4723" is the 47th week of 2023.

The compound in a winter tire hardens as it ages whether you drive on it or not. Past six years, start watching. Past ten, replace it regardless of how much tread is left. A hardened winter tire is an expensive all season.

This is the check people skip, and it is the one that catches a set that looks perfectly serviceable.

3. The flexibility test

Press your thumbnail into a tread block. New winter rubber gives slightly. Old hardened rubber feels like a hockey puck and does not deflect at all.

This is rough and subjective, but if you have a new tire to compare against, the difference is obvious. Compare against your all seasons if that is all you have.

4. Sidewall and tread inspection

Look over the whole tire, inside sidewall included, which means turning the wheel to full lock or getting the car up.

Replace immediately if you find:

• A bulge or bubble anywhere. That is a broken internal cord and it can let go at speed.
• Deep cracks in the sidewall or at the base of tread blocks.
• Any exposed steel cord or fabric.
• A cut deep enough to see into.

Worth asking about but not automatically fatal:

• Fine surface crazing, which is an age indicator.
• An old plug or patch. A properly done internal patch is a permanent repair. A plug on its own is not, and a repair in the shoulder or sidewall is never valid.

5. Uneven wear and the snowflake

Run your hand over the tread, front to back and back to front. Feathering, where the blocks feel smooth one way and sharp the other, points to alignment. Cupping, where there are scalloped dips around the circumference, points to worn suspension or a persistent balance problem.

And confirm they are actually winter tires. Look for the three peak mountain snowflake symbol on the sidewall. That is the only marking that means the tire met a snow traction standard. An "M+S" marking on its own does not; that is a tread pattern claim with no performance test behind it.

Plenty of people discover at this point that the set they have been calling winters are all seasons.

What to do with the answers

All five pass: mount them, set the pressures to the door jamb spec, and have them balanced. Pressures need setting cold and they will need topping up again after the first real cold snap.

Depth is marginal: consider whether you want to get through a full winter on them. A set at 5/32 in November is probably below 4/32 by March, which is exactly when you need them most.

Age is past ten, or anything in step 4 failed: replace them.

Not sure: bring them in. We will measure the depth properly, read the dates, and look at the inside sidewalls, which is where the problems hide. We will tell you straight whether they have another season in them.