How Winter Tires Enhance Safety in Snow and Ice

Before getting started, alert readers will surely notice we are calling these hoops ‘winter tires’ instead of ‘snow tires’. This is thanks to advancements in rubber technology which permit this type of tire to add tractive benefits when ambient temperatures are below 7C/45F instead of only when a layer of snow covers the driving surface. Winter driving often includes battling the white stuff, especially in the snow belt, but extra traction in simple cold weather can also be of massive benefit.

The tractive properties of a tire are generally guided by two vastly different (but equally important) types of features: molecular and mechanical. The former is informed by the secret brew that is its rubber compound. This is a closely guarded secret mixture that can be silica- based and which, in winter tires, permit the rubber to stay flexible in cold temperatures, explaining why a Michelin Pilot Sport 4S will send you skidding into a snowbank despite its phenomenal summertime grip. Meanwhile, the latter speaks to whatever type of grip pattern a company has chosen, referring to features like sipes and amount of void between tread blocks.

Molecular properties play a key role but are largely invisible, just like parents of Gen Xers back in the ’80s and ‘90s. It is all but impossible for someone not employed by a tire company to suss any sort of compound detail just by looking at a tire; yet, it is those compounds which allow a winter tire to remain pliable and grip the road surface when the mercury drops into a thermometer’s nether regions. Poorly selected compounds, which can appear on budget off-brand tires, tend to remain rock hard compared to the molecular structure of known quantities like the Lapland-engineered Nokian Hakkapeliitta. Strides are also being made by newcomers like Sailun to effectively replicate what’s on offer atop the totem pole. In other words, don’t be taken simply by an impressive tread pattern.

Which is a great segue into the importance of mechanical features on a winter tire. Rubber companies spend years and untold square acres of money on this puzzle, trying thousands of designs before settling on an option which offers great grip without deafening passengers with road noise or braking the bank with extra fuel consumption thanks to outrageous rolling resistance. Tread patterns are comprised of blocks, between each of which will be a void. Even these empty spaces are carefully considered, since tire companies have learned these areas, when full of snow, actually add traction to the equation. For a great example of this phenomenon in action, try walking over ice in winter boots with clean soles versus a pair with snow stuck to them.

Tread blocks on a winter tire need to be designed with one eye on grip and another on the evacuation of water or slush. They are often packed with little zig-zag cuts called sipes, mentioned earlier, whose job it is to open ever so slightly when pressed into a driving surface and bite into the snow or ice. As an example, take a piece of Styrofoam from the next Amazon package which arrives at your door and slide it across yer kitchen table. Moved pretty easily, right? Now, take a blade and carefully make a series of shallow cuts in the Styrofoam and try sliding it across the table again. Different, hey? That’s sipes at work, or the basic concept behind them.

A good tread pattern with effective blocks will also contribute to lateral grip, meaning the tire won’t lay over and die the first time it is shown a corner. This is no small puzzle since cornering forces can act very differently on a tire compared to braking and acceleration forces. Experienced winter drivers generally accept that while all-wheel drive certainly helps with acceleration, winter tires help tremendously with turning and stopping. Such a belief certainly explains why, time and time again, tow truck drivers can be found hauling SUVs shod with all-season tires out of snowbanks in northern parts of our country.

Glad you stuck around for the lesson? As are we. Choosing the right tire for winter conditions can make the difference between making it to hockey practice and making a call to the insurance company.

[Lead image: Everyonephoto Studio/Shutterstock.com. Product image: Manufacturer]

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