How we test tires

To evaluate all aspects of a tire, we put it through a number of objective and subjective tests in the most comprehensive tire-test program of any American magazine or Web site.

We test braking and lateral grip on dry and wet surfaces, handling in our emergency-avoidance maneuver, and hydroplaning resistance, which measures how well a tire maintains contact with the road in standing water. We rent a local skating rink to test braking on ice. We have outside labs evaluate tread life and rolling resistance. To ensure consistency, we buy each tire model in the same size and mount them on the same test cars.

You might notice that a tire's rating has changed from previous tests. That's because new models coming onto the market can eclipse the performance of older ones. And continual improvements to our test procedures can affect how some tires score.

Starting with these tests, our tire Ratings are now designed so that you can compare the individual performance of one type of tire with another. For example, you can compare the Ratings of all-season and winter tires to see how much dry and wet grip you give up with winter tires in return for better snow and ice traction. The overall score, however, is still relative to each tire category.

Because tread life can influence driving safety, our tread-life rating is included in each tire's overall score. Tires that wear quickly can more easily become worn beyond safe levels.