Mountain Snowflake

Mountain snowflake tires
Wikimedia Commons

Perhaps you're wondering if that All-Season tire you're looking at is really winter-capable, or if it's designed more for wet and dry weather. Perhaps you're wondering what that mountain thing on your winter tires really means in terms of performance. Let's look at the history of the Mountain Snowflake.

In 1999, the Rubber Manufacturers Association (RMA) and the Rubber Association of Canada (RAC), with assistance from the US Department of Transportation and their Canadian counterpart, Transport Canada, came to an agreement on a standard by which tires that performed to a certain level in grip tests over packed snow could be branded with an identifying symbol – a snowflake superimposed on a mountain, the so-called “Mountain Snowflake.”

Basically, the tire must “attain a traction index equal to or greater than 110 compared to the ASTM E-1136 Standard Reference Test Tire when using the ASTM F-1805 snow traction test”, according to the American Society for Testing and Materials (ASTM) procedure, “RMA Definition for Passenger and Light Truck Tires for use in Severe Snow Conditions.”

In English, this means that the tire wanting to wear a Mountain Snowflake has to have 10% better snow grip than the standard reference tire everybody uses. I would say that most decent winter tires wear the symbol, except I wouldn't call a winter tire “decent” without it in the first place. There are also certain All-Season tires that qualify for the Mountain Snowflake, primarily Nokian's WRG2 and WRG3.

That's an important thing to know in Canada and the northern US, in fact, the city of Quebec now requires all passenger vehicles to install tires bearing the Mountain Snowflake from December to March. In the past few years, this has actually tended to deform the North American winter tire market somewhat in the late fall as Canadians buy large quantities of winter tires. This is one reason I always recommend looking for snow tires around the beginning of football season.

However, not everybody thinks that the Snowflake is still good enough to denote a true winter tire. In recent years, Transport Canada has begun to push for a higher standard to be required for the Mountain Snowflake symbol. Nigel Mortimer, Head of Recalls in the Safety and Security group at Transport Canada says that “the snowflake is not doing the job anymore.” Mortimer argues that the reference tire, ASTM E-1136 is in fact, an All-Season tire, and that winter tire technology has “evolved greatly” since 1999. "Some modern winter tires are now at 130 or 140 percent of the control tire's performance. We need to move to a higher standard."

Personally, I agree. Testing against an All-Season reference tire is just not good enough, particularly given the revolution still ongoing in winter tire technology. It's probably a good time for RMA and RAC to start looking at making the Mountain a bit higher.