treadsheet

Winter tires in Canada

Winter tires use a softer rubber that stays grippy in the cold, plus deeper tread with lots of small slits ("sipes") that bite into snow and ice. Below about 7°C, all-season rubber starts to stiffen and lose grip, which is the usual rule of thumb for when to switch.

Where they're required

Quebec

Required on all passenger vehicles from December 1 to March 15. Tires must carry the mountain-snowflake symbol.

British Columbia

Required on many designated highways, mostly from October 1 to March 31 (April 30 on some mountain routes). M+S or mountain-snowflake tires qualify; signs mark the routes.

Ontario

Not required, but insurers must offer a discount if you use winter tires.

Rest of Canada

Not required by law, but strongly recommended anywhere it regularly drops below freezing.

Rules change; check your province's transport ministry before you rely on dates.

How to tell it's a real winter tire

Look for the three-peak mountain snowflake on the sidewall. It means the tire passed a standard snow-traction test. "M+S" (mud and snow) on its own is not the same thing: most all-season tires carry it. "All-weather" tires carry the snowflake too, and can stay on all year, but give up some ice grip compared with a dedicated winter tire.

Why many people use smaller wheels in winter

A common winter setup is one size smaller wheel with a taller, often narrower tire, for example going from a 19-inch wheel to an 18-inch one. This is called "minus-sizing". A taller sidewall cushions potholes and is cheaper, and a narrower tire cuts through snow better. Tires in smaller sizes are usually cheaper too.

To do it safely:

  • Keep the overall height within about 3% of the factory size so your speedometer and stability systems stay accurate. The tire size calculator shows this instantly.
  • Make sure the smaller wheel clears your brakes. Many cars can't go below a certain wheel size because of the brake calipers. Ask a tire shop or check your owner's manual.
  • Match the bolt pattern and center bore of your car. Every vehicle page lists them.
  • Load rating must meet or beat the one on your door sticker.

Fit four, not two

Always install winter tires on all four wheels. Winter tires on only the front or rear make the car behave unpredictably, especially when braking or turning on ice.

Should you buy a second set of wheels?

Mounting winter tires on their own wheels costs more up front, but saves on seasonal mounting and balancing, protects your nicer wheels from salt, and makes each switch quicker. Steel wheels are the budget option. If your car has tire pressure sensors, ask whether the winter wheels need their own.

Start with your factory size: find your car, then check the "Other sizes that fit your factory wheels" section, or compare a smaller-wheel option in the calculator.