I am no tire expert, but I can tell you all this: When I put my Firestone Blizzak's on the Chrysler minivan it is like day and night difference between them and the Michelin highway tires that they replace. They offer much more traction to get going and to stop in both ice and snow conditions. Of course they are not worth a darn in hot weather, and need to come off in April at the latest around here. And of course they wear much faster than the Michelins also as they are much softer. Believe it or not, they offer better traction going up my steep gravel covered hill in dry conditions at low speeds also. I can go up it without tire spin going very slowly, which I cannot do with the Michelin's. With the Michelin's on, I must alway hit the hill with some speed or risk spinout. So that is my 2 cents, that winter tires with the little mountain/snowflake on them make a huge difference. That's all I know.