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There?s a popular myth that rolls around every year at the cusp of winter that all-season radial tires will get you through the snowy season.
While there?s ample evidence of many crash-free winters using just this practice, those stories usually comes from the temperate southern states and the west coast of North America. In northern states and almost all of Canada ? places where winter is actually cold and snowy ? driving through a winter on all-seasons without a major incident can be attributed more to sheer luck.
The biggest difference between an all-season tire and a winter tire is not so much tread pattern, though that plays a part, but the rubber compound in the tire. Just like clothing can be made of a blend of fibres ? polyesters, cotton, nylon and so on ? a tire for all seasons or each season is likewise comprised of various rubber compounds. It?s the type and blend that makes one tire better in summer than winter; an ?all-season? tire is really just a compromise.
Truth is, winter tires are made of a denser rubber compound than all-season tires ? and more of it. More importantly, the compound is designed to stay malleable during colder temperatures, allowing them to provide the grip all tires are designed to deliver. An all-season tire, on the other hand, is made of less rubber that makes for a smoother and adequately grippy ride in the summer, but tends to harden up when there?s a chill.
Technically, a moderate 7 degrees Celsius, or 45 degrees Fahrenheit, is roughly the threshold where non-winter rubber starts to harden. Generally speaking, once the temperature drops below -10 C / 14 F, almost every all-season tire behaves more like hardened plastic than flexible rubber on asphalt. It takes little imagination to figure out what that might do to your ability to stop or steer in a jam.
Then, of course, there?s tread. All-season tires have a tread pattern meant to provide you with a comfortable, quiet, low rolling-resistance ride. But for all that, such a tranquil tread pattern is too tight to effectively grip snow (or mud, for that matter), much like wearing sneakers where you should be wearing hiking boots.
Winter tires have tread patterns spaced out to better allow them claw at snow rather than smush over it. These aggressive tread patterns are also what makes winter tires louder to drive on and often produce slight vibration when driving on dry roads.
This is to say nothing of studded winter tires ? genuine ?snow tires? ? which have steel nubs embedded in their rubber to act like cleats. Major grip in those, but even more noise and vibration because of it.
So why does the ?all-season tires for all winters? myth persist? Probably because it?s true some of the time. Again, it?s a regional thing. All-season radials usually perform just fine in rain and even the occasional dusting of snow, typical of southern states and on up the west coast.
By that same token, summer or all-season tires are the better bet when it?s summer, obviously, or any season that doesn?t involve cold and snow. They won?t wear as quickly as a winter tire driven in summer months, and they provide a better grip on smooth surfaces. The low rolling-resistance also equates to better fuel economy.
Meanwhile, the last couple of decades have seen great strides in tire technology, making the difference between winter and all-season tires technically disparate yet hardly noticeable to the end users.
From a consumer standpoint, as with any product, you get what you pay for when picking tires. The quality of the tire compound (and the associated price tag of the tire) will determine things like how much cold weather your tires can endure before they start to act like plastic ? and how effective they?ll be in the meantime.
Fortunately, you don?t have to rely solely on tire salesmen for the technical minutia of such things. There are some great online resources that allow you to research and better understand the plethora tires and tire types on the market today. Among the best of these is tirerack.com, which not only offers an interactive tire finder for your make and model of car, truck or SUV, but a wiki on winter tire facts and stats.