When you look closely at any road surface it is really not that smooth as represented by the model in this picture
The engineers who design those high grip summer performance tires we love so much, also know this and use it to their advantage.
They incorporate high grip rubber compounds that conform to the irregular surface of the road. That much surface contact can generate tremendous amounts of traction for cornering, accelerating and braking.
but, what if the road in snow covered?
That brings us to the question, what makes a tire a good winter tire? The answer is a three part puzzle and without all three parts traction will be compromised.
- let's look at the first part of the puzzle; tread design
this winter tire utilizes a large number of sipes which is a typical feature found in winter tire tread designs
when the road gets snow covered the tire is no longer able to conform to the surface.
The siping in the tread design allows the tread elements to flex under stress which creates aggressive "biting edges" when braking, cornering or accelerating
- part two of our three piece traction puzzle is tread depth
In most parts of the world, tires are considered to be legally worn out when they reach 2/32" (approximately 1.6mm) of remaining tread depth. U.S. law requires tires to have easy-to-see Tread Wear Indicator bars running from one side of their tread design to the other when the tire's tread has worn down to the minimum legal limit of 2/32 inch.
We here at The Tire Rack recommend that drivers expecting to encounter snow-covered roads consider replacing their tires when they reach approximately 6/32" of remaining tread depth to maintain good mobility. Tires need more tread depth in wintry conditions to compress snow in their grooves and release it as they roll. If there isn't sufficient tread depth, the "bites" of snow that can be processed on each tire revolution will be reduced to "nibbles," and the vehicle's traction and mobility in snow will be reduced.
- The third and final part of the puzzle is the rubber compound
Rubber compounds vary widely from manufacturer to manufacturer but, the task is the same so, you will see some similarities between the products. They all typically use compounds which utilize materials designed to remain flexible at cold temps in addition to traction enhancements from silica, fibers and other materials which add more bite on ice.
My name is Luke Pavlick and I am a Car Guy