Originally Posted by Forum Rules and FAQ - READ BEFORE POSTING

<FONT SIZE="4">Tires FAQ</FONT>


Winter tires are designed for use on snow and ice, and in frigid temperatures. They grip better than all-season tires in such conditions, even when the roads are dry. On warmer days, their handling is sloppier than all-season tires. For this reason, they are recommended for winter use, not year-round use.

There are several types of winter tires:

a. Tires that have the very best traction on snow and ice, but have so-so ride and handling on days when it's not so cold. Recommended examples include the Bridgestone Blizzak REVO1 and WS-60, Dunlop Graspic DS-2, and Michelin X-Ice. (The Tire Rack calls these tires "studless ice and snow tires".)

b. Tires that have good traction on snow and ice and in cold, although not quite as good as the previous group, but they also have very good ride and handling characteristics on days when it's not so cold. Recommended examples include the Bridgestone Blizzak LM-25, Dunlop Winter Sport M3, and the Michelin Pilot Alpin PA2. (The Tire Rack calls these tires "performance winter tires".)

The choice between these two categories depends on the climate in your area, how much highway driving you do in the winter, how much you care about ultimate snow/ice grip versus ride comfort, whether you have another vehicle to use in the worst of winter, etc. Oh, and the tires in category (a) are usually significantly less expensive than category (b), which may be important. For example, if you live in an area with harsh winters and you want want the best snow/ice traction during the winter and don't mind sacrificing some ride comfort and handling for those few months a year, you may prefer category (a) tires. If you care more about ride comfort or if you live in an area with somewhat mild winters, you might be better off getting the category (b) tires.

All-season tires are the most flexible in terms of ambient temperatures, as they are designed to be used in frigid winter cold and on snow, as well as in moderate to warm temperatures. The downside of this flexibility is that their performance in most conditions is not as good as tires designed specifically for those conditions. In winter conditions, all-seasons perform better than summer tires but not as well as winter tires; in moderate to warm temperatures, they perform better than winter tires but not as well as summer tires. If you need to use the same tires all year round, in winter conditions (frigid cold, snow, ice) as in moderate to warm temperatures the rest of the year, then all-season tires are a good choice. Recommended all-season tires include the Kumho Ecsta ASX, Pirelli PZero Nero M+S, and Bridgestone Potenza RE960AS Pole Position.

One additional advantage of all-season tires is that they tend to last longer (more miles) than summer tires or winter tires. For this reason, if performance is not a priority, all-seasons may be fine for your family car or commuter car.

Some people mistakenly believe that all-season tires are needed for rain performance. This is not true; good all-around summer tires like the Goodyear F1 GS-D3 and Kumho SPT are outstanding in rain, better than all-seasons.

Originally Posted by AN OVERVIEW OF STUDDED AND STUDLESS TIRE TRACTION AND SAFETY

1. Studded tires produce their best traction on snow or ice near the freezing mark and lose proportionately more of their tractive ability at lower temperatures than do studless or all-season tires.

2. The traction of studded tires is slightly superior to studless tires only under an ever-narrowing set of circumstances. With less aggressive (lightweight) studs being mandated, and with the advent of the new “studless” tire, such as the Blizzak, since the early 1990s, the traction benefit for studded tires is primarily evident on clear ice near the freezing mark, a condition whose occurrence is limited. For the majority of test results reviewed for snow, and for ice at lower temperatures, studded tires performed as well as or worse than the Blizzak tire. For those conditions in which studded tires provided better traction than studless tires, the increment usually was small.

3. The precise environmental conditions under which studded tires provide a traction benefit are relatively rare. The maximum frictional gain (in comparison to nonstudded (not studless) tires) is found for new studded tires on smooth ice, where they have been shown to provide up to 100 percent gain in certain tests. However, the relative frictional gain of studded tires diminishes or becomes negative on roughened ice, as the temperature drops, as the studs wear, or if the comparison is made with studless tires.