The Wizardry Behind Toyo's Open Country A/T III All-Terrain Tires
It has everything to do with that little snowflake you see on the sidewall.
By Matt Crisara
Courtesy Toyo Tires
While most all-terrain tires are capable of going off-piste, they struggle in the winter months when temperatures, and therefore grip levels, begin to plummet. We're increasingly aware of this eventuality as we stare down the prospect of driving in snow. But if you see a snowflake symbol on your tires, you're in good shape, as it means that they meet the Three-Peak Mountain Snowflake (3PMSF) traction rating. Toyo's latest Open Country A/T III—which we've been driving in southern Pennsylvania conditions—is a good example of how 3PMSF has incentivized manufacturers to design their tires to preserve all-terrain performance while eking out more winter usability. On the surface it sounds like an easy job, but cold-weather convenience comes at the detriment of year-round performance and tread life, which is what engineers need to balance when gunning for 3PMSF.
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Before we get into the specifics, some background. In helping drivers gauge the snow-​worthiness of a tire, the U.S. Tire Manufacturers Association and the Rubber Association of Canada agreed in 1999 to a performance-based traction rating for truck and car tires. Denoted with a Three-Peak Mountain Snowflake symbol (which appears on the tire sidewall as a snowflake inside a mountain), the designation requires that tires pass a series of tests in snow. This is measured through an acceleration test through hard-packed snow designed by the American Society for Testing Materials.
Open Country A/T III
Toyo Tire walmart.com
Ahead of the test, the tires are cooled down to match the air temperature. During the evaluation, the road surface must have at least .75 inch of medium-packed snow on top of 1.2 inches of hard-packed snow—with ambient temperatures around 5 to 25 degrees Fahrenheit. The test will then measure the distance it takes the vehicle to reach 6 mph and then how fast it can go from 6 mph to 15 mph. Shorter distances equate to better traction. Any tire that does 110 percent better than an all-season control tire gets the 3PMSF label.
We chatted with Jonathan Benson, an independent tire testing expert and founder of Tyre Reviews, and he stressed the importance of the jack-of-all-trades nature of these types of tires. "The 3PMSF marking doesn't mean it's an exceptional tire in winter conditions, but it does mean it has some tested winter capabilities, which is a step above a non-3PMSF-marked all-terrain tire," says Benson. An American-market all-terrain tire, 3PMSF-marked or not, will never match the grip of a dedicated winter tire.
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While the Three-Peak Mountain Snowflake rating isn't supremely difficult to achieve, it still requires some clever engineering where the rubber meets the road. Material properties of the tire compound can have a profound effect on handling. Snow tires use a compound that remains pliable at lower temperatures to extract more grip. However, this decreases tread life considerably, which is why a 3PMSF–rated tire like the A/T III has to compromise. This is where engineers earn their paycheck, adding materials like silica, bamboo powder, and sometimes even crushed walnut shells for added bite in winter—allowing the rubber to keep the same firmness.
Another useful tool for adding winter performance is siping. These are small slits inside the tread blocks that increase the number of biting edges in the tread. Sipes provide a cavity that pulls away the small layer of water on top of the ice to provide more grip. Contrary to popular belief, stud-less tires can produce plenty of traction on ice after dispersing this layer of water. While the added grip through winter conditions is invaluable, sipes also add traction in wet conditions and promote even tread wear throughout the life span of the tire.
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The tread pattern is also paramount when it comes to extracting maximum all-weather performance. Compared to the previous-generation Open Country A/T II, the A/T III has added lateral grooves to enhance overall traction, along with stone-ejecting blocks and staggered shoulder lugs to enhance traction in soft terrain. Toyo also optimized the acoustics of the tire, which becomes especially useful in the summer months on the highway. As each size of tread block produces a different frequency of sound, the A/T III has various sizes and shapes of tread block, specifically tuned to produce a lower frequency that's less noticeable.
As the only interface between you and the road, a good set of tires can make or break the drivability of your vehicle—which sits on a contact patch of only a few square inches at each wheel. This is why tires are one of the most engineered parts of your vehicle. Toyo's Open Country A/T III, and other 3PMSF-rated all-terrain rubber, is great for cold-weather climates with plowed roads and limited snowfall. However, swapping to a dedicated winter tire will always be the way to go for drivers in alpine climates where snow accumulates.
Anatomy of the Toyo​ Open Country A/T III
To the untrained eye, the Open Country A/T III tires are nearly identical to any other all-terrain rubber that you'd see rolling down the road. However, Toyo has optimized the rubber compound, sipe design, and tread pattern to produce a tire that meets the Three-Peak Mountain Snowflake rating.
Winter Driving Best Practices
With winter months on the horizon, it's time to think about getting your vehicle ready for the conditions. We reached out to Team O'Neil Rally School in Dalton, New Hampshire, for some tips to keep you pointed in the right direction.
While winter tires are essential when snow begins to accumulate, you're not totally dead in the water if you're running all-season rubber. If you have no other option, it's important to at least ensure that your tires are properly inflated and have an adequate amount of tread left over. With at least 50 percent tread depth, you'll be fine in cold and wet weather, but driving in deep snow with all-seasons still isn't advisable.
Look where you want to go
Despite this phrase being repeated ad nauseam when you were learning how to ski or snowboard, your instructor was right. Humans have a natural tendency to move in the direction they're looking. However, target fixation is a real problem that can put you at risk when things start to go south. Therefore, when you lose traction, don't stare at what you're going to run into; shift your focus to where you want to end up.
Limit your inputs
While your first inclination in an emergency situation will most likely involve slamming on the brakes or aggressively swerving around an oncoming obstacle, these are easily the worst things you can do in the winter. Any sudden movements like these will lead to a loss of traction. Gradual inputs will help you maintain control.
Focus on one thing at a time
It doesn't take a racing driver to realize that there are three stages to every corner: braking, turning, and accelerating. Despite the colossal investment that manufacturers incur on research and development, your tires are only good at doing one of those things at a time. When approaching a corner, it's important to brake in a straight line, turn the car, and accelerate out of the corner in a straight line.
Test the conditions
Grip levels are subject to change in the winter. This is why it's a good idea to start out slow to get a feel for things in a safe area—not the public road—before you approach other traffic. This can be as simple as tapping the brakes to see how far you can go before locking up, or jiggling the steering wheel to find where your front wheels will bite. We repeat: Don't do this on the main roads or in any location that could create an incident.
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