Make Sure Your Tires Have Enough Tread for a Snowy Winter
CR testing shows that tires can lose their winter grip at half-tread depth
In wet and wintry weather, all-season tires begin losing traction long before they appear worn-out, according to Consumer Reports’ testing. Tread depth is essential to disperse rainwater and slush and claw at snow. As tires wear, this ability to hold the road confidently fades.
In CR’s tire tests, we started to see a decline in the performance of tires with half their tread depth still left—well before most drivers would consider replacement.
Photo: John Powers/Consumer Reports Photo: John Powers/Consumer Reports
How CR Tested Winter Traction
To assess the impact of tread depth on winter traction, we compared the performance of three popular all-season tires—one set with a full tread and one with only half the tread left.
Tests Show How Tread Depth Impacts Winter Traction
A tire with a half-tread depth usually has 5/32 to 6/32 of an inch remaining. Tires are worn out when they reach 2/32 of an inch, but you don’t need to go that low to see a substantial decline in performance on slick (wet, snowy, or icy) surfaces.
On average, with the half-tread tires, there was:
- A 14 percent decline in snow traction (based on the measured distance that it takes a vehicle to get up to speed).
- An 8 percent loss in hydroplaning resistance (based on the observed speed at which hydroplaning first occurred while driving through standing water at our test track in Connecticut).
- A 7 percent loss in wet braking (based on the stopping distance from 60 mph on a wet surface, measured at our test track).
- A small loss in braking ability on ice (based on the stopping distance from 10 mph on the surface of a Connecticut ice rink).
Photo: John Powers/Consumer Reports Photo: John Powers/Consumer Reports
When to Replace Tires
To monitor your tire’s tread depth, buy a tread-depth gauge from an auto parts store or simply use a quarter to judge whether the tires need replacing. If the top of George Washington’s head is just visible when placed head first in a tread groove, the tread has about 4/32 of an inch depth. That’s enough to offer some all-weather grip, but you’ll want to start shopping for replacements. When any tire groove is at 2/32 of an inch, it’s worn out and needs immediate replacement. You can check by using a penny; the distance from the top of Abraham Lincoln’s head to the bottom of the penny is 2/32 of an inch.
Bottom Line
All-season tires perform well for more modest snow conditions. But as the test results show, if the tires are more than half-worn, you may want to wait out the snowstorm until the roads have been cleared.
Knowing that winter is coming, even if the tires are at 5/32 in the fall, you should start shopping because winter-friendly tires tend to get harder to find as the year winds down. This means that a tire store may need to order the tires for you, and deals may be harder to come by.
See our picks for the best all-season tires.
Shopping for Tires?
See our tire ratings and buying guide.
