Wednesday November 28, 2012

Do I really need snow tires? This time of year I get a lot of tire related questions. In this column, I will explain the differences between snow tires and all season tires and how you might benefit by putting snow tires on your vehicle.

Snow or winter tires vary in several areas from all season and summer tires. The most obvious is usually the appearance of the tread. Snow tires have a much more open tread and larger tread blocks and lugs so as to cut through the snow and allow it to clean out of the tire where it meets the road. Tread depth is usually deeper to allow more slush and snow to pack in the tread while still allowing the lugs to maintain traction. Probably the most important feature of winter tires is the "tread compound." The tread compound is the formulation of the tire’s tread rubber. In order for a tire to achieve traction in cold temperatures, the tread has to remain soft and flexible in temperatures down to zero degrees or below. Summer and all season tires begin to get too stiff in temperatures of 25 degrees and below. As the temperature gets colder, the tire’s tread gets harder and less flexible and you get the effect of, for instance, your hard rubber lawn mower wheel. If you commute or travel a lot in the winter, keep that in mind when driving at high speeds when the temperature is around zero or below. Your all season or summer tires will not stick to the road like in warm weather, which will hamper not only cornering, but also braking.

What about studded snow tires? Studded snow tires provide the ultimate traction on ice and extremely hard pack conditions by incorporating tiny metal studs embedded in the tread. Driving with studded tires does create considerable noise and they don’t handle or stop as well on dry roads.

Years ago when most cars were rear wheel drive, it was common to put the snow tires only on the rear wheels. Today, the majority of the cars we drive are front or all wheel drive. The recommendation now is to put snow tires on all four wheels. By fitting four snow tires on your vehicle, the cornering and braking will be even, hopefully preventing fish tailing, wheel lock up and general unbalanced handling. Even though putting four snow tires on is a considerable investment, you now have eight tires to alternate and will get good even wear out of all of them.

Let’s take it a step further: four snow tires mounted on their own wheels. This practice has become more and more popular. By doing this you don’t have to go through the mounting and balancing twice a year. It’s much faster and less costly to swap your summer wheels out with the premounted winter ones. Stack them up out of the sun and weather and they will be good for the next season.

If you are inclined to keep all season tires on year round, just be sure you have adequate tread depth. Tread depth of below 5 or 6/32 becomes ineffective in snow. Some vehicles are just better than others in winter conditions. Many four wheel and all wheel drive cars and trucks do quite well with all season tires on them. A lot depends on where you have to travel. Commuting from Bennington to Mount Snow? You probably will need some good tires.

For safe winter driving it’s good to not only have your car checked over, but also to give your tires a good close look. It’s better to be safe than sorry.