Cooper Tire Discoverer AT/W Tire Review

I’m a firm believer that there’s no such thing as an all-season or all-weather tire.

For those who live in regions with four proper seasons, the temperature swing from mid-summer to mid-winter is so dramatic that a tire needs to compromise in one season to perform well in another. But Cooper Tire wants to change all that and claims to have created a proper, all-year capable tire.

Called the Discoverer A/TW, the new tire is designed for pickup trucks and large SUVs. Cooper chose the truck and SUV segment to release the new tire as the company felt it was the best fit to allow a proper, twelve-month tire to be created. Many have tried this idea before, especially with passenger car tires and failed. With trucks and SUVs, Cooper very well may have succeeded.

Despite being an all-season tire, the new Discover A/TW is actually certified to be run in regions that require dedicated winter tires like Quebec, Canada. Appropriately, Cooper Tire brought me to Mecaglisse Motorsports Park in Quebec during the middle of winter to test the new AT/W out. Located over an hour north of Montreal, Mecaglisse is a winter motorsports wonderland full of snow and ice tracks that twist and turn up and down the hillsides of central Quebec.

To earn winter certification, a tire needs to be adorned with the snowflake symbol on its sidewall. Cooper warned us that this doesn’t mean much. The company is actively campaigning for the process to earn winter certification to be stricter. Currently, the test is too simple. Basically, to earn certification a new tire needs only to marginally out accelerate a twenty-five year old all-season tire on snow. There’s no braking, handling, ice or extreme cold temperature testing to achieve that snowflake on the tire’s sidewall. What’s more, the Tiger Paw that is used is not the new one, but a version designed twenty-five years ago.

The reason Cooper Tire is looking to increase the winter certification difficulty is that the company believes the Discoverer A/TW far exceeds the relatively easy certification process and matches the ability of a true winter tire. For starters, unlike most all-season tires, the A/TW features full tread sipes. Thinner than the company’s regular winter tire sipes, the A/TW’s still work to provide extra grip in ice and snow.

SEE ALSO: Cooper Tires Weather-Master S/T 2 Winter Tire Review

The tire’s glassification point is really what makes it so impressive. Glassification is the point where a rubber tire becomes hard like glass. When this happens, its ability to provide traction and grip greatly decreases. A normal all-season tire has a glassification point usually around 45F. With generous use of silica, the A/TW has a much lower glassification point; one not far off of most winter tires.

Silica is more than just the secret sauce that keeps tires flexible at low temperatures. It also allows increases tread life, reduces rolling resistance and adds traction, all at the same time. So why doesn’t every tire come crammed full of silica? Well, it’s expensive to cure into the rubber and it’s highly abrasive to the manufacturing equipment.

But enough about the tire’s design; I was in Quebec to put it to the test. For evaluation, Cooper brought along the Discoverer A/TW and it’s Canadian-market X/T4 sibling. Equipped to Chevrolet Tahoes, the tires were being compared to the Firestone Winterforce UV, a dedicated winter tire. The test included slow speed slaloms, incline braking, incline acceleration, emergency lane changes, downhill cornering and panic braking.

Although this was all closed course testing on a snow encrusted track surface, some clear observations could be made. First and foremost, the Discoverer A/TW and X/T4 couldn’t quite match the abilities of the Winterforce in terms of cornering and agility. But the gap in performance is small. In back-and-forth maneuvering, the Firestone is more willing to grip during sudden directional changes. All three tires performed similarly on the downhill cornering though and were very predictable at the edge of traction.

SEE ALSO: Cooper Tire CS5 Touring Tire Review

Braking is a draw between the tires as all offered the same level of grip and stability. When it came to acceleration, especially during the uphill portion, the Discoverer tires actually outperformed the Winterforce. The overall performance gap to this dedicated winter tire is the closest I’ve ever experienced in an all-season tire. If I were to rate the Firestone as a 9 out of 10 in winter ability, the A/TW and X/T4 would have to be at least an 8.5 out of 10.

Remember though, the AT/W is as much of a summer all-terrain tire as a winter tire. With chevron grooves, stone ejector ribs and cut & chip compounds designed into the AT/W, Cooper assures me the tire still has good off-road capabilities. The actual performance should fall just short of Cooper’s true winter Mud & Snow tire, but the AT/W’s tread life is also much longer.

And since the tire is meant to handle hot temperatures, warm wet performance should be better than dedicated winter tires that get too soft and stops performing properly. Plus, winter tires can wear-out up to 40 percent faster when driven all year around as their rubber compound is not meant for hot temperatures. There’s only one way to really find out if the AT/W performs as well in warm weather as it does cold weather and that’s a proper test in the heat. Luckily Cooper Tire has a giant proving grounds near San Antonio, Texas, with on- and off-road courses that I plan to evaluate the AT/W on later this spring.

Fast Facts:

With over 1.9 million miles of testing, Cooper Tire is confident the new AT/W and XT/4 siblings are ready for all year around abuse. For now, the tire is only designed for larger SUVs and pick-up trucks available in 16- to 20-inch wheel sizes. Besides adding more wheel sizes, the company did hint that it may expand the range in the future to include the booming small crossover market. Impressive in the snow, if the AT/W can live up to its claimed abilities in the summer as well, this could very well be one of the first, true, all-weather tires.