Winter tires aren’t just for getting around snow-covered race tracks with the quickest lap time or drifting around icy back roads like a seasoned rally pro. Their real purpose is to make treacherous winter roads and conditions safer for the average driver. It’s easy to cast winter tires off as something only die-hard enthusiasts drool over and shop for, but there’s a reason parts of Europe, the U.S. and Canada have laws establishing dates on when winter tires are either mandatory or highly recommended. Knowing how and why cold-weather tires work is a useful nugget of knowledge when you do go shopping for a set.
The grip that high-quality winter tires can provide doesn’t just allow your car to handle better; in fact, it’s proven that that same grip cuts stopping distances by a considerable margin. When ice and snow enter into the picture, grip and handling become paramount — and elusive. Winter tires of old attempted to claw back performance in snowy conditions with just chunky, heavy-tread rubber that paddled through the snow. The key to cold-weather performance is actually more subtle than that. Tread pattern does play its part (more on that in a moment), but it’s the tire’s rubber compound that plays the biggest role.
The rubber that makes up summer tires and all-season tires is designed to work in higher temperatures. So to avoid complete self-destruction during a spirited jaunt through Malibu Creek State Park in mid-July, the rubber is inherently harder, allowing it to work better as it softens thanks to higher temperatures. Conversely, winter tires are made with softer material, right out of the gate, so that when temperatures dip, they’re still pliable and can still grip cold pavement and packed snow and ice.
Tread-pattern design has evolved from the idea of bluntly shoving snow and water out of the way to actually channeling it — and using both to get even more grip. A soft rubber compound may grip the ground better when a cold fronts roll in, but nothing grips snow like — well, snow. If you look closely at a modern winter tire like the Pirelli Sottozero 3 (pictured), each larger tread block has smaller sipes and channels that purposefully hold on to snow so that it can hold traction in the worst possible conditions (say, a snow-blanketed golf course in Switzerland, like the one at the Pirelli Winter Experience). It’s the same sort of physics that allows you to pack snowballs and build snowmen: snow sticks to snow very well.
Don’t think of winter tires as a “performance extra” that you could actually do without, like a superficial spoiler or carbon fiber cosmetic bits. Winter tires return control, stopping power and handling to you; so, when forecasts start to call for progressively lower temperatures, you should consider winter tires just as helpful and important as power steering, ABS and traction control. You wouldn’t want to drive through a blizzard without those, would you?