What's the story on 'all-weather' tires?

All-weather tires are, in effect, winter tires that can be used all year long

Published: November 27, 2014, 7:15 PM
Updated: August 27, 2020, 5:37 PM

Winter tire on ice

For those to whom cost and storage of a second set of tires is a concern, a new type of tire is gaining popularity – the 'all-weather' tire. Note the name: not all-SEASON but all-WEATHER.

That one-word difference can make the difference between sliding off the road or into a collision or remaining in control in winter conditions. 

All-weather tires are, in effect, winter tires that can be used all year long.

Winter tires

Modern winter tires have proven far superior to all-season tires for winter driving because the tread remains supple as the temperature drops. The crossover in performance begins at about 7 degrees Celsius.

From that point downward the advantage of the winter tire increases. At about -14 degrees the tread of the all-season tire typically becomes as hard as a hockey puck, and slides on ice or packed snow just as easily.

In addition to remaining flexible and able to grip the surface at cold temperatures, winter tires have thousands of tiny little zig-zag cuts known as sipes.

They increase the number of contact edges and as the tread passes over the surface they open and pull in water, which results from melting of the ice at its point of contact with the tire, and expel it as the tire rotates.

The tread itself has large individual tread blocks with broad spacing between them designed to pull in and cast off snow in the same manner.

Winter Tire - Mountain-Snowflake symbol

Winter tires must meet a rigorous set of test conditions in order to carry the Transport Canada pictograph symbol of a snowflake within a mountain.

All-season tires do not meet these standards. They contain the ubiquitous and ambiguous M S symbol which does not require any testing at all related to their actual performance in winter conditions.

All-weather tires

But the new all-weather tires do meet the stringent snow/winter test standards. The difference between them and pure winter tires is that the all-weather tires can be left on your vehicle year round.

Nokian, a tire company base in Finland is credited with creating this new class of tire more than a decade ago. Since then, many other major tire makers have joined the movement.

But beware: some off-brands and independent tire retailers may misrepresent M S tires for those worthy of the mountain/snowflake symbol. Make sure that symbol is on the sidewall of any tire you purchase for winter use.

Generally speaking, all-weather tires were developed for use in urban areas where the roads are plowed and maintained. If you live in a very remote or rural area or have to drive through heavy snow frequently a proper winter tire, or even an old-fashioned snow tire, with its much more aggressive tread, is for you.

The tread of an all-weather tire is designed to remain flexible over a wide range of temperatures.

The specific and ultra-secret combination of oils, carbon black, rubber, synthetics, chemicals, belts, etc, has been developed to stay soft as the thermometer plunges, but not so soft as to wear prematurely and provide poor grip in the summer months. Heat is the enemy of winter tire; wear is accelerated as the softer tread squirms around and traction, or grip, is thus reduced.

All-weather tires are still a compromise. They're not as good as high-quality winter tires in winter nor as good as all-season or summer tires in the hot months.

The ride may also be stiffer and, because they provide more rolling resistance than good all-season or summer tires, you can expect increased fuel consumption and higher noise levels.

Another factor to consider if you plan on installing all-weather tires, driving through the summer and keeping them on next winter is that the summer driving will wear the edges off the tread blocks, the very edges that contribute so much to winter grip.

On the plus side, their stiffer sidewalls and higher speed ratings usually mean all-weather tires carry a higher tread wear rating, some as high has 100,000 km.

For many Canadians, especially those with storage or cost issues, they may be the answer.