In the world of ¾- and 1-ton trucks, there are four main tire categories, which range from extreme off-road to exclusively highway use: mud-terrain, all-terrain, performance, and highway. Mud-terrain tires are designed for rugged adventures through the wilderness, navigating across all types of terrain—mud, snow, rock, and desert. All-terrain tires are engineered for solid on-road performance with added grip for dirt, snow, and wet surfaces, making them an appealing choice for occasional light-duty, off-pavement excursions. Performance tires are engineered to help trucks and SUVs achieve near-sport-car-like pavement traction, enabling maximum acceleration, braking, and handling. Highway tires are designed to provide all-season performance to balance comfort, handling, and a quiet ride and are installed on vehicles that may never encounter off-pavement driving or be pushed to their mechanical limits. Toyo Tires has an improved design for the all-terrain tire category: the Open Country A/T II.
| toyo Open Country A T Ii Review tire
Gathering input from resellers, installers, and consumers, the engineers and designers at Toyo Tires set out to improve the all-terrain tire, thereby creating the new Open Country A/T II tire. Creating a tire to perform equally well off-road as it does on-road is not an easy task. The typical characteristics required for a great performing off-road tire have a negative effect for a well-mannered, on-road performance tire. Consider the tire requirements for the given off-road terrains and the adverse effect to street performance.
Rock: Tires for rockcrawling require both sidewall flexibility and puncture resistance, while also providing numerous biting edges per square inch.
Street effect: Loose cornering and noisy
Snow: Soft and flexible winter tires are able to grip the terrain surface better and provide traction. The second most important element of a good snow tire is siping. Sipes are the little cuts in the tread blocks, and they provide additional biting edges for grip in wet and icy conditions.
Street effect: Reduced longevity
Mud: Good mud tires typically have a high void ratio and an aggressively tapered lug design that allows the tread to eject mud as the tire rotates. This cleaning effect keeps the lugs from becoming clogged, allowing them to maintain a solid grip with the loose surface.
Street effect: Noisy and prone to hydroplaning
Understanding these tradeoffs, the engineers at Toyo Tires had a difficult task ahead of them: design a capable off-road tire without compromising on-road performance. They began by identifying the important attributes and then setting design goals.
| Top: Polygonal blocks and zigzag sipes provide increased contact area for improved traction, benefiting wet\icy\snow-driving conditions.
Middle: Deep grooves with stone-ejecting blocks help prevent the tire from collecting rocks, mud, and snow.
Bottom: Tie bars between blocks improve dry braking and provide added rigidity for even tire wear. All of these design characteristics work in concert to make the Open Country A/T II tire a sound choice for an all-terrain tire.
Best in class on wear performance:
Optimum footprint and state-of-the-art compound helps boost wear performance over competitors.
The Open Country A/T II has a significantly longer expected mileage performance than the Bridgestone Dueler, BFG A/T T/A KO, and others. (A copy of the third party test report may be requested by contacting Toyo Tires).
Noise:
Be as quiet as possible throughout the entire life of the tire.
Collaborated with Japanese OEM to develop state-of-the-art technology to produce an extremely quiet tire.
*Wear-out indicators, side blocks, and channels are designed for outstanding performance through the life of the tire.
On- and off-road performance: The Open Country A/T II offers excellent off-road performance while maintaining excellent ride quality.
Winter performance was one of the critical performance attributes.
They also wanted a more aggressive-looking tire—after all, aesthetics are important, too.
To accomplish these objectives, major emphasis on design uniformity and tire roundness were paramount. Balance and uniformity of roundness of the tire is maintained throughout the fabrication process, unlike the traditional drum assembly used by competitors. Achieving improved levels of uniformity and balance means better ride/lower vibration, and the tire requires less weight to balance. The proprietary manufacturing technology developed by Toyo Tires gives the company an edge over the competition.
We mounted a set of the Open Country A/T II tires on our ’07 Chevy 2500HD and put a few thousand miles on them. In addition to highway and city driving, our testing included towing in excess of 12,000 pounds and desert off-roading. Although we performed most of the testing in the arid southwest, we were able to evaluate the tire in wet and dry conditions. Did the folks at Toyo accomplish the design objectives? Absolutely! Admittedly, our test of 3,000 miles is far short of the advertised 50,000-mile treadwear warranty, so we asked for a copy of the third-party projected mileage test results. The report indicates the new tire should have a longer tread life. For a tire that performs so well off-road, it is exceptionally quiet.
| Lowering the tire pressure to increase the contact surface between the ground and tire is a common practice in rockcrawling and traversing deep sand. Notice how the tread on the sidewall is now employed as a traction aid. This works just as well in mud and sand. WARNING: This technique of reduced tire pressure is only approved for slow speeds. The tires must be inflated to proper pressure before normal driving is resumed.
We tested the Sound Pressure Level in decibels (dB) from 50 mph at 725 rpm to 75 mph at 1,425 rpm, and there was only a difference of 5dB—or 1.5 times louder. However, there was a 10dB or 2 times increase from 725 rpm to 1,425 rpm. Therefore, some of the increase in sound level is directly attributed to the engine noise. The on-road manners of the Open Country A/T II are quite impressive, too. The advanced manufacturing process and high-quality control process are appreciated in the overall ride and comfort of this tire. The tires do not shake or vibrate at high speeds, and the under-steer (front tires lose traction or “push”) is significantly improved from the M\T tires we replaced.
Although 2500HD trucks are not known for great cornering, we were able to hold a tighter line with less scrub, or chatter, during skid testing. We believe this to be a benefit of the polygonal (many sided) blocks, tie bars between the blocks, and plethora of zigzag sipes. Towing, braking, and wet driving also benefited from the improved traction. The deep tread grooves with stone-ejecting blocks do an adequate job while not creating the annoying hum of mud-terrain tires. The open tread blocks carry onto the sidewall of the tire to provide the bite we needed to back our 12,000-pound trailer in the mud at the landfill. While others were spinning their wheels, the Open Country A/T II slung the mud and bit into terra firma to get the traction we needed to back into place.
The saying “beauty is in the eye of the beholder” applies to tires, too. To be perfectly honest, we prefer the look of the Toyo Open Country M/T tire. However, the Open Country A/T II is a far more aggressive and better looking tire than the competitors’ all-terrain tire.
| Heavy towing on gravel roads or asphalt is no problem for the Open Country A/T IIs. The design of the tire improves braking and handling by maintaining constant contact with the ground. With a load rating of “E” at 3,195 pounds, it is an adequate replacement. Better yet, lower inflation pressure at the specified load rating translates to a softer ride, and tire noise levels are kept to a minimum, too.
The all-terrain tire category has a lengthy list of objectives to meet. As the name infers, the tire is expected to perform in a multitude of environments under various road conditions. Toyo Tires developed a proprietary manufacturing process, which enables it to produce high-quality, tightly controlled, performance products. The Open Country A/T II is a symmetrical design for superior handling, superior wear, and lower rolling resistance, while also having an aggressive, attractive tread design.
Tire as Tested
Tire Type: Radial
Tire Size: 35x12.50x17LT
Overall Diameter: 34.5 inches
Overall Width: 12.58 inches
Tread Depth: 17⁄32 inch
Weight (per tire): 69.9 pounds
Approved Rim Width: 8.5 to 11 in.
Load Index: 121R
Maximum Load (tire): 3,195 pounds
Load Range Rating: E 10-ply
Maximum PSI: 65 psi
Sidewall: 3-ply
Tread: 3-ply polyester + 2-ply steel + 2-ply nylon
Available Sizes: Nearly 100 different SKUs are available to fit 15-, 16-, 17-, 18-, 20-, and 22-inch rim diameters. Metric widths range from 215 to 325mm with 85- down to 50-series profiles. Fitments also include 30X9.5R15 up to 35X12.5R20.
Warranty: The Open Country A/T II includes up to a 65,000-mile warranty and qualifies for the Toyo Tires No Regrets 45-day, 500-mile trial offer. Tires are available for OE upgrades on pickups and SUVs, from midsize to 1-ton capacity—for that custom, plus-size appearance, and for high-torque diesel pickups.
