Although born in Texas, my stepfather taught me a great deal about winter driving, to include the importance of tires. Back then he changed the tires.. When the trees came back to life in spring, the summers tires were put on. Fall meant pulling the snow tires out of the rafters and having them mounted. That's just the way it was in Colorado.
Tire technology advanced over the years, and decades, and all-season radial tires became the norm. They lasted longer, gave us better gas mileage, better control and could be driven all year round. True snow tires actually became harder and harder to find. Thankfully tire manufacturers have brought back tires made for snowy winter driving; winter tires. What's the difference? Tread design and composition.
Many all season tires qualify for Mud & Snow ratings. The grooves, called sipes, channel water away and provide the ‘bite’. But snow and ice can easily clog the generally thin sipes, which essentially leads to a brand new tire gripping like a worn out bald tire. All-season tires are generally made from a harder, more plastic-like compound. This gives them a longer life, but they become even stiffer in the cold.
Winter tires on the other hand have both narrow sipes for water and large lug-like grooves to bite into the snow. As the tire rotates, snow is flung out. This continual process keeps the tire gripping so you can keep moving. Snow tires are generally made from softer material, designed to remain soft even in the cold. Many tire manufacturers actually use a sponge-like material. Tiny voids in the rubber create a place for the thin surface layer of water a place to go, giving the tire a solid grip on ice.
The Rubber Manufacturers Association (RMA) is the keeper of the ratings tire manufacturers must meet to with regards to this area. Tire ratings for Mud & Snow versus Winter have significant differences.
The requirements for the Mud & Snow rating are based solely on the tread design. They have no requirements for the composition or the tire’s performance. Again, tread design only. Qualifying tires will have the letters “M” and “S” on the sidewall. (M&S, M/S, M+S..etc.)
To qualify as a winter tire, or as the RMA calls it, a Severe Snow Use tire, certain performance standards for traction must be met. Tread design and materials contribute to making winter tires preferable when Old Man Winter comes to town. Testing has shown these tires significantly shorten stopping distances and are less likely to lose their grip when accelerating or cornering. These tire have the mountain and flake logo next to their M & S imprint on the sidewall.
It all comes down to safety. Safety, safety, safety….. Which brings us to Colorado’s Passenger Vehicle Traction Law and its associated Chain Law. Improper tires and violations of Traction and Chain Laws can lead to a $500 fine and a huge tow truck bill.
Winter tires generally cost more. So you may want to read the previous paragraph again before you decide on which tire to buy this year.
Going too fast is what sends most cars off the highway; no tire can save your car when Newton’s Laws of motion take control. But proper tires can get you moving. Combined with safe speed, (I'm talking speeds way below what most people feel comfortable at), winter tires play a critical role in keeping Sir Isaac out of the driver's seat.
Master Sergeant Donald Enloe
Colorado State Patrol District 1