Mountain snowflake or M+S: which winter tires count in BC?

3 minute read · Checked October 2026 · Written at the Harkness counter, Coppervale, BC

The short answer

Both count in BC. The law accepts a tire marked with the three-peak mountain snowflake or the letters M+S, as long as it has at least 3.5 mm of tread. The two marks mean different things. The snowflake means the tire passed a snow traction test, and the province recommends it for cold weather driving.

What does the mountain snowflake symbol mean?

The symbol is a mountain with three peaks and a snowflake inside it. Canada's federal tire rules spell out what earns it. The tire is tested for traction on packed snow, then compared with a standard reference tire. It has to beat that reference by a set margin before the maker can mould the symbol on the sidewall.

The rubber matters too. Transport Canada notes that all-season and summer tires start to lose elasticity below 7°C. A tire built for winter keeps its grip at much colder temperatures. The Tire and Rubber Association of Canada says dedicated winter tires stay flexible well below minus 30. On a minus twenty morning, that soft rubber keeps your tires biting.

What does M+S mean on a tire?

M+S stands for mud and snow. A tire earns the letters by meeting a tire industry specification for that label. BC's regulation names that specification as one of the ways a tire can qualify. Most all-season tires carry M+S, and the Tire and Rubber Association of Canada describes them as suited to moderate snow and slush.

An M+S tire with 3.5 mm of tread or more is legal on signed BC routes. The trade-off shows up in deep cold and on packed snow. All-season rubber begins to stiffen below 7°C, according to Transport Canada. Snowflake tires pull ahead from there.

Mountain snowflake or M+S: which should you buy for the Kootenays?

For Kootenay driving, we recommend the snowflake. The province makes the same call. It recommends three-peak mountain snowflake tires for cold weather driving, and chains on board for extreme conditions. M+S meets the legal minimum. The snowflake tire is the one built for the Kootenay Pass in January.

Think about where your car spends its winter. If you cross the passes on Highway 3, drive Forest Service Roads, or start the car at minus twenty, snowflake tires earn their keep. If you stay in the valley on bare, salted pavement, an all-season tire with M+S still meets the law. We will talk it through at the counter and show you the sidewall.

Where do all-weather tires fit in?

All-weather tires carry the mountain snowflake, so they are legal winter tires in BC. They are built to stay on the car all year. The Tire and Rubber Association of Canada says they grip better than all-seasons without the symbol. It also says they are designed for year-round use and moderate snowfalls. A dedicated winter tire is built for winter alone, with softer rubber for deep cold.

An all-weather set can make sense if you drive mostly in town and want one set of tires. If you drive the passes often, we usually suggest a dedicated winter set on its own rims. Our guide on whether a second set of rims is worth it runs the numbers. When you are ready, book a tire changeover and we will fit whichever set you choose.

Asked at the counter

Can I mix snowflake and M+S tires on one car?

BC law needs at least two matching winter tires on the drive axle. Transport Canada goes further and advises four tires of the same type, size, speed rating and load index. Mixed tires make a car less stable, so we fit winter tires in sets of four.

How much tread does a winter tire need?

At least 3.5 mm to count as a winter tire in BC. Transport Canada also advises against using tires worn close to 4 mm on snow-covered roads. We measure every tire at each changeover and tell you where yours sit.

Are snowflake tires worth it on an all-wheel-drive car?

Yes. All-wheel drive sends power to all four wheels, which helps you get moving. Stopping and turning depend on the grip of the tires alone. The province's rule applies to 4x4 vehicles for the same reason.

Do snowflake tires need a different tire pressure?

Use the pressure on the label in your driver's door jamb, whatever tire you run. Cold weather drops tire pressure, so a tire set in a warm garage reads low outside. Check them cold, before you drive.

What we checked

BC Laws, Motor Vehicle Act Regulations, Division 7 (ss. 7.161, 7.162, 7.1635, 7.164) · checked 2026-10-05
Justice Laws, Motor Vehicle Tire Safety Regulations (SOR/2013-198), winter tire definition and date code · checked 2026-10-05
BC Government, Passenger vehicle tire and chain requirements · checked 2026-10-05
Transport Canada, Using winter tires · checked 2026-10-05
Tire and Rubber Association of Canada, Tire Basics fact sheet · checked 2026-10-05
Tire and Rubber Association of Canada, British Columbia winter tire law · checked 2026-10-05
Tire and Rubber Association of Canada, all-weather and dedicated winter tires · checked 2026-10-05