Tread Depth Tire Chart: What Is Safe for Winter Tires?
On a tread depth tire chart, new winter tires start near 12/32 inch, you should replace winter tires at 4/32 inch, and a tire is legally bald at 2/32 inch. Transport Canada advises against using any tire below 5/32 inch, about 4 millimetres, on snow-covered roads. Winter tires lose their bite long before the legal limit, so the 4/32-inch replace point matters more than the 2/32-inch legal one.
Tread is what lets a winter tire bite snow and clear slush, and it fades gradually, so you rarely notice the day it stops being safe. A simple tread depth tire chart turns that guesswork into a number you can check in your driveway. Here is what the key depths mean for winter grip, how to measure with a Canadian coin, and when worn tread crosses from legal to dangerous.
What the tread depth tire chart says for winter
The numbers matter because winter performance drops long before a tire is bald. A new winter tire starts at about 12/32 inch of tread. By roughly 6/32 inch it is about half worn and its snow and slush grip is fading. Transport Canada advises that tires worn close to 5/32 inch, 4 millimetres, should not be used on snow-covered roads. Tire makers and most provinces set the winter replace point at 4/32 inch, while 2/32 inch is where any tire is legally worn out. So on a snow tire tread depth chart, 4/32 inch is your real line, not 2/32.
What do the numbers on a tread chart mean?
Tread depth is measured in thirty-seconds of an inch, which is why every winter tire tread depth chart reads like 12, 6, 4, 2 over 32. That is just how far down the grooves go: a brand-new tire is around 11 to 12/32, and the tire is done when the grooves wear to 2/32. For winter tires the useful range is narrower than for all-seasons, because the deep channels and biting edges that handle snow stop working well below about 5/32. A tire tread depth chart simply lays those thresholds out so you can see where your set sits rather than guessing by eye.
How to check tread with a coin
You do not need a gauge; a Canadian coin works. For the toonie test, slot the coin into a groove: if the tread reaches the bear's paws, you have plenty left and the tires are likely near new; if it covers only the silver outer ring, they are about half worn; if it reaches only the letters, they are worn and due for replacement.
The quarter test is the quick winter check: put the quarter in with the caribou's nose down, and if the tread covers the nose you have adequate depth, but if you can see the nose, replace the tires soon. That is how to check tire tread depth in under a minute, and it is close enough to tell safe from spent.
When worn tread makes winter tires unsafe
Below about 5/32 inch, a winter tire can no longer clear snow and slush well, so stopping distances stretch and the tire aquaplanes sooner, exactly when GTA roads are worst. By 4/32 inch the winter edge is largely gone even if plenty of rubber remains, which is why the minimum tread depth winter tires should run is higher than the legal bald point. Below 2/32 inch you are both unsafe and, in most provinces, driving on illegally worn tires, which can bring a ticket and weaken your position if you are ever in an at-fault collision. The wear bars moulded into the grooves mark that minimum: when they sit flush with the tread, replace the tires right away.
What a worn set means for your next winter
If your check shows you are near or below 4/32 inch, plan on a new set before the season rather than gambling on one more winter. A half-worn winter tire still looks fine but stops noticeably longer on snow, and the gap only widens as it wears. Knowing your size makes replacing them simple, and the best time to line up a set is early, before the autumn rush firms up prices. Share your size and the cohort does the rest.
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Frequently asked questions
What tread depth is safe for winter tires?
Replace winter tires at 4/32 inch. They start near 12/32 inch, and Transport Canada advises against using any tire below 5/32 inch (4 mm) on snow-covered roads. A tire is legally bald at 2/32 inch.
What is the minimum legal tread depth in Canada?
2/32 inch is the legal worn-out point for a tire in most provinces. For winter grip, though, you should replace well before that, at 4/32 inch.
How do I check tread depth with a coin?
Use a toonie or quarter. With a quarter, caribou nose down: if the tread covers the nose you have adequate depth; if you can see the nose, replace the tires soon.
Why replace winter tires at 4/32 and not 2/32?
Because winter traction fades long before the legal limit. Below about 5/32 inch a winter tire stops clearing snow and slush well, so 4/32 inch is the practical replace point.
What are the little bars in my tire grooves?
Tread wear indicator bars, moulded into the grooves to mark the minimum tread depth. When they sit flush with the surrounding tread, the tire is worn out and should be replaced.
Sources
- Kal Tire, when to replace winter tires and how to measure tread (4/32 winter, 2/32 legal, coin tests, wear bars): kaltire.com
- Kal Tire, how to measure tread depth (quarter test, 12/32 new): kaltire.com
This guide is general information for GTA drivers, not legal advice. Tread-depth rules vary by province, so confirm the regulation where you drive and have worn tires inspected. Whollar does not sell tires.