"The concept of an all-terrain is to have a tire that works well in all conditions, including rain-soaked highways, where mud-terrains sometimes falter," says Ali Mansour with Four Wheeler magazine. "While the tighter voids prevent most all-terrains from excelling in the mud, for most daily-driven 4x4s, the modern all-terrain tire works extremely well." The increase in traction (versus the street-friendly all-season tire) results in more tread noise, a stiffer ride and lower fuel efficiency. And though the best models can manage deep snow, all-terrain tires tend to be pretty slippery on ice.
That said, there are exceptions. The Cooper Discoverer A/TW (Est. $180) still can't supplant a good winter tire like those profiled in our report on snow tires, but it does represent a good compromise for use in most U.S. climates. Mike Schlee at AutoGuide.com puts the A/TW through tests in summer and winter and comes away very impressed, saying that the it's one of the rare tires that "truly makes me sit up and take notice." He adds that, for winter use, the overall performance gap between it and a dedicated winter tire is the smallest he'd seen in an all-season tire. The results of his summer tests are even more upbeat. He finds nearly nothing to gripe about with performance on wet and dry roads, or when off-roading. "The Cooper Tire Discoverer AT/W may not be the cheapest tire on the market, but in my experience, it's one of the best," he concludes.
One reason that the A/TW is so good in winter is that it's one of the few all-terrain tires to carry the snowflake severe winter rating symbol. That means it has about 10 percent more acceleration grip on the white stuff than a standard tire, reports Ken Brubaker at Four Wheeler Network. He adds that the manufacturer claims that the A/TW far exceeds those standards, though his ability to vet that personally had been limited at the time of his review. However, he does test out the tire in the summer: "We put thousands of road miles on the tire throughout the summer and found it to be a well-wearing, very smooth tire," Brubaker says, adding that performance was good on both wet and dry roads, and that it nicely survived being "purposely mistreated" off road.
The Discoverer A/TW is also put on the test bench in a large, comparative review, and does well enough to rate as one of a handful of Recommended choices. It rates Good or better on every measured parameter, including a Very Good rating for snow traction.
One factor gave us a little hesitation in naming the A/TW our Best Reviewed choice. There are very few user reviews, at least on the U.S. side of the border. But up north, in Canada, where the A/TW was available earlier than in the U.S., it's received a warm reception from drivers used to tackling frosty roads. Customers reporting at Canadian Tire give the A/TW a 4.5 star rating. Two of the nearly 30 that weigh in aren't as impressed as the experts when it comes to winter performance, but every other owner rates the tire at 4 stars or, mostly, 5 stars.
If dealing with icy roads isn't a concern where you live, or a factor in what you are looking for in an all-terrain tire, our former Best Reviewed pick, the Cooper Discoverer A/TW (Est. $155) still qualifies as a good choice. During his test, Josh Burns with Off-Road.com says the Discoverer A/T3 tracks "straight through the deep mud" and delivers great "control and traction" on wet roads. Other Off-Road.com testers say it "resembles a tire more at home on the highway with a five-rib design that can channel water, but the silica-based tread compound grabs dirt and pulls through hard-pack trails." Users say the Cooper's construction is durable and chip-resistant.
In one large test, the AT/3 scores well in many of the attributes off-roaders most care about, including braking on dry surfaces, resistance to hydroplaning, handling and ride comfort. It's traction in snow is also fairly decent, however braking performance on ice is fair at best. That leads that reviewer to conclude that the AT/3 is "A very good choice for areas where icy roads are rare."
If you spend most of your time on the highway, but want a tire that can go off road on occasion, the Michelin LTX A/T2 (Est. $190) doesn't exhibit quite the same level of four-wheeling grip as the Coopers, but it gets very good scores for ride quality and performance under a variety of conditions, including in snow. It's on the list of recommended tires provided by one expert reviewer, with tread life a high point, and that's backed by a six-year, 60,000-mile coverage on treadwear.