How Much Tread Is Left?
Short answer: put a Canadian quarter in the groove, caribou nose down. If the tread reaches the nose, you’ve got about 6/32″ or more and you’re fine. If you can see the whole nose, start planning. Legal is 2/32″ — but that’s a floor, not a target.
The Coin Test
You don’t need a gauge. Two coins cover the range that matters:
- Quarter, caribou nose down. Tread reaches the nose в†’ roughly 6/32″ or better. Good.
- Penny or nickel, if you still have one. If the tread doesn’t reach the top of the letters, you’re near the legal limit.
Check three places across each tire — inner groove, middle, outer — and check all four tires. Uneven wear tells you as much as the depth does.
What the Numbers Actually Mean
| Depth | What it means |
|---|---|
| 10–11/32″ | New passenger tire |
| 6/32″ | Half worn. Fine in the wet, marginal in snow. Our minimum for a used tire. |
| 5/32″ | Winter tires stop working as winter tires. Replace before the season. |
| 4/32″ | Wet braking distance is climbing noticeably. Start budgeting. |
| 2/32″ | Legally worn out in Ontario. Well past sensible. |
Tread doesn’t give you grip on dry pavement — a slick tire grips dry road best. Tread exists to move water out from under the contact patch. When it’s shallow, water has nowhere to go, and at highway speed the tire starts floating instead of gripping. That’s why the difference between 8/32″ and 3/32″ barely shows up on a dry day and shows up dramatically in a downpour on the DVP.
Read the Wear Pattern Too
- Both edges worn, middle fine — chronically under-inflated
- Middle worn, edges fine — over-inflated
- One edge only — alignment, usually camber or toe
- Scalloped or cupped patches — worn suspension, or a wheel that’s been out of balance for a long time
- Front pair much worse than rear — normal on front-drive cars, and a sign you should be rotating
Also Check the Date
Rubber ages whether you drive on it or not. The DOT code on the sidewall ends in four digits — week and year. A tire with plenty of tread and ten years on the clock is still a tire to replace, especially if it’s been sitting outdoors.