| gmal:
Part of the problem is summer-performance tires are just that; tires with hard rubber compound designed to take the punishment of spirited driving under hotter conditions. When the hard "summer" rubber compound is exposed to colder (or freezing) temperatures the compound stiffens, reducing roadsurface traction, AND accelerating tread wear.
Interesting comments; If this is true then how do they get away with it when they sell/market the ALL SEASONS tires? are they made of different rubber compounds? or the whole issue revolves around the tread design of tires. i.e. grooves, smooth, rough, water channels etc etc. | 
