We just completed the second part of our winter tire testing program, which included measuring stopping distances on ice. In January, we performed tire snow traction testing, aided by the good fortune of having plenty of the white stuff at our Connecticut test track to evaluate the all-season, all-terrain, and winter tire models. (See our previous truck tire testing update.)
Our tests for braking on ice are conducted on an indoor ice skating rink at speeds just over 10 mph, and the process requires a panic stop before hitting the boards at the end of the rink. You might not think that 10 mph is very fast until you find yourself sliding into a wall--that's when the grip between a good and poor set of tires can make the difference of being in accident or avoiding one.
The graph shows the average stopping distances of the 23 all-season, 13 all-terrain, and 12 winter tires fitted to our Chevrolet Tahoe. The bracket within each category bar shows the range of stopping distances among the best and worst models. On average, winter tires make good on their claim, stopping shorter than all-season and all-terrain models that promise to have similar performance. But as the range shows, some winter tires stop no better than some better-gripping all-season and all-terrain tires. Incidentally, the longest stopping all-season tire was also the one with least snow traction grip. Overall, the best gripping winter tire stopped near an impressive 25 feet; the worst performer took over 47 feet. That's a 22-foot difference or well more than a car length. We can only imagine what that difference would be at higher speeds.
Bottom line: if icy conditions are common in your region, a good set of winter tires might just make the difference in getting to your destination safely. Regardless, icy roads are a challenge for any car and tire, so it's important to slow down and to drive carefully.