General Questions
Winter tires are like any other replaceable component on your car — their lifespan is directly related to the quality of the product that you buy and the type of use that it sees. Rubber softness, UV exposure, tire construction, and vehicle weight all figure into the equation. And because winter tires are usually designed to work best within a narrow temperature window, their durability is often drastically reduced when they’re operated outside that window.
In other words, what you get out of a winter tire has a lot to do with what you put into it. Buy a super-soft Finnish ice tire and drive it year-round? You’ll be lucky to see two winters out if it. Throw your expensive Bridgestone Blizzaks into the back yard for the kids to play with and the sun to bake all summer? Ditto. But if you store your winter tires properly (indoors, away from light and heat) and limit them to winter use only, then several seasons of safe driving isn’t unheard of.
That said, there is one caveat: Unlike most summer tires, which actually become grippier in the dry as they wear, winter tires require tread depth to work. The average snow tire produces its maximum traction on snow and ice when it’s brand-new. There’s no hard and fast rule, but once a tire reaches 6/32″ of tread depth, it’s probably due to be replaced. You can still benefit from the tire’s softer compound and winter-oriented construction — in other words, a snow tire at 4/32″ is better than an all-season or summer tire at 4/32″ — but there’s no sense in purposely handicapping yourself. Remember, too, that most tire manufacturers design their winter tires so that the rubber gets harder as the tire wears down; this feature helps dry-road longevity but ultimately hampers winter traction as the tire ages.