October 16, 2015
Regardless of why you may consider outfitting your truck, SUV or Jeep with On-/Off-Road All-Terrain tires, one look at their deep, aggressive tread pattern tells you what they’re all about.
Beyond the rugged good looks that can enhance the swagger of your off-road machine, On-/Off-Road All-Terrain tires are built from the ground up to dig their way through loose dirt and sand, slog through mud, scramble over rocky terrain, or give you the mobility to get in and out of a tough job site.
When you think about what it takes for the all-terrain tire to cope with the tough environment and endless variety of conditions encountered when driving off-road, dealing with the dry, wet or wintery conditions found on paved roads starts to look like a much easier task. And to that end, typical Highway All-Season tires feature shallower tread depths and mild tread patterns that roll along smoothly and quietly as they grip terra firma. Highway All-Season tires aren’t equipped to handle serious off-roading, beyond navigating a dirt driveway or rolling down the two-track to the local boat ramp.
For most drivers already using all-terrain tires, most of their miles are spent on the paved roads that link periodic off-road adventures or driving needs. To that point we routinely get a common question from vehicle owners considering the switch from road-going Highway All-Season tires to more aggressive all-terrain tires: what are the differences or trade-offs in on-road driving behavior?
To help answer that question, the Tire Rack team conducted a Real World Road Ride and Performance Track Drive comparing the General Grabber AT 2 (On-/Off-Road All-Terrain) with the General Grabber HTS 60 (Highway All-Season). Our evaluation used 2016 Porsche V6 Cayennes fitted with new, full tread depth 255/55R18 tires mounted on 18x8.0 wheels.
It’s a given that an On-/Off-Road All-Terrain tire will outperform its Highway All-Season counterpart when asked to keep moving after the pavement ends, so off-road testing wasn’t included in our evaluation. This test isn’t about picking a winner and loser; it’s about understanding the inherent differences between two vastly different tools for the job.
Our 6.0-mile loop of expressway, state highway and county roads provides a great variety of road conditions that include city and highway speeds, smooth and coarse concrete, as well as new and patched asphalt. This route allows our team to experience noise comfort, ride quality and everyday handling, just as you would during your drive to school or work.
As you might expect, our drivers found the on-road manners of the Highway All-Season General Grabber HTS 60 to be superior. This tire handled well, did a good job controlling the ride by smoothing over the bumps and sharp impacts, while also producing only modest tread noise as it rolled along. If all you do is drive on paved roads, this would be a great choice for many drivers.
Despite the deep and aggressive tread pattern of the Grabber AT 2, some of our drivers found the handling to be better than they expected and quite adequate for the task, with steering inputs taking just a little longer to turn into action. Ride quality for the all-terrain tire was reasonably good, actually feeling a little more supple than the Highway All-Season tire when rolling over smaller single impacts. But when it encountered sections of broken pavement or repetitive high frequency stutter bumps, the compliant all-terrain tire would begin to resonate and jitter a little more than the tight, controlled ride of the Highway All-Season tire. Our test tires were P-metric sizing and load capacity, so be prepared for a potentially larger impact on ride comfort if your vehicle normally comes equipped with P-metric tires, but the tire size and product you choose is heavier duty load range D or E light truck ("LT") tire.
The single biggest difference in normal road driving we found between the two tires was the tread noise. A number of our drivers commented on how the noise level of the Grabber AT 2 was lower than expected, but no one could call it quiet. A steady growl was easily heard at any speed above 20mph, and never went away even at higher speeds when wind noise usually overcomes the minor pattern noise of highway tires.
Our 1/3-mile per lap test track course includes 90-degree street corners, a five-cone slalom and simulated expressway ramps. Run in both dry and wet conditions, the test track allows our team to experience the traction, responsiveness, handling and drivability normally only encountered during abrupt emergency avoidance maneuvers or competition events.
In dry conditions, the Grabber HTS 60 highway tire felt responsive, stable, and delivered good braking and cornering traction. During the abrupt maneuvers of our handling course, the Grabber AT 2 all-terrain tire felt predictable, albeit with a little less precision and somewhat lower overall grip than its Highway All-Season counterpart.
Wet conditions showed a greater difference between the two tire types. Here the Grabber AT 2 all-terrain tire again displayed predictable handling, but its off-road capable tread compound couldn’t hold the wet pavement of our track as well as the Grabber HTS 60 highway tire could, resulting in a slower lap time and longer braking distance. It’s not hard to imagine that the all-terrain tire’s tread rubber chip- and tear-resistant compound blended to withstand thousands of rugged off-road driving miles wouldn’t be as pliable as the tread rubber used on the mild-mannered highway tire like the Grabber HTS 60 in our test.
Winter weather is often unpredictable, and snow-covered roads change with every passing vehicle as they churn snow into slush or pack it down to polished ice. A constantly changing test surface makes side-by-side comparisons difficult, so we use a dedicated winter testing facility in Northern Sweden with acres of groomed snow that provides the consistency we need to get reliable acceleration and braking comparisons. This facility also has a prepared snow-handling course where we evaluate the stability and control of each tire during abrupt maneuvers. To simulate the icy conditions found at intersections or the black ice experienced out on the highway, we use ice at a local hockey rink and measure acceleration and braking traction.
Some drivers gravitate to an all-terrain tire’s aggressive tread pattern as their choice for winter season driving. And to that end a handful of On-/Off-Road All-Terrain tires are marked with the three-peak mountain/snowflake Severe Snow Service symbol that indicates they achieve a higher level of traction (than a standard all-season reference tire) in a packed snow test. Many of the sizes of Grabber AT 2 do have the Severe Snow Service symbol on their sidewall, although some sizes have not been tested and therefore aren’t marked with the symbol. Our test size is one that isn’t marked, but it does feature the same aggressive tread pattern found across the range of sizes, and we expect delivers similar ultimate winter performance.
On the ice we found no significant difference between the two tire types. This underscores the reality of the three-peak mountain snowflake Severe Snow Service test, which does not evaluate ice traction. But on packed snow we found the Highway All-Season tire provided better traction than the all-terrain tire. Acceleration traction was fairly close, but the difference became greater and more obvious when trying to stop or especially turn our test vehicle. We did not have an opportunity to test the deep snow traction differences between these tires, where the digging potential of the more aggressive all-terrain tire may begin to claw back some of its deficit to the Highway All-Season tire.
Our Real World Road Ride features a relatively flat 6.0-mile loop of 65 mph expressway, 55 mph state highway and 40 mph county roads along with two stop signs and one traffic light every lap. Our team drove each tire approximately 500 miles over the course of several days. Since we wanted to compare fuel consumption results that typical drivers would experience, our drivers were instructed to maintain the flow of traffic by running at the posted speed limits and sustain the vehicle’s speed using cruise control whenever possible. They did not use hypermiling techniques to influence vehicle fuel economy.
| Tire | Test MPG* | Gallons/Year @ 15,000 Miles |
% vs. Most Efficient |
|---|---|---|---|
| General Grabber HTS60 | 22.7 | 660.8 | -- |
| General Grabber AT 2 | 22.0 | 681.8 | -3.2% |
| *Our evaluation used Race Technology DL1 data loggers to record true distance travelled. | |||
While none of the tires in this test were designed with low rolling resistance as a high priority, we did find a moderate difference in observed vehicle fuel economy between these two tires. The deeper tread depth and blocky, open tread pattern of the all-terrain tire needed more energy (fuel consumed) to roll than its more efficient Highway All-Season counterpart. Based on our results the 0.7-mile per gallon difference in observed fuel economy would result in an annual difference of about 21 gallons of premium gasoline. At the current cost of $2.00/gallon, it would amount to $42 for drivers driving 15,000 miles per year.
It’s important to note our test’s fuel consumption measurements follow consistent procedures designed to minimize variables that could influence the results; however they do not represent an exhaustive long-range fuel consumption study. While our procedures require the test vehicles in each convoy to run under the same prevailing conditions, the week-to-week differences in ambient temperatures, barometric pressures and wind speeds that we experience over a season of testing can influence vehicle fuel consumption and prevent the absolute mpg values of this test from being compared directly against those of others.
Larger differences in consumption between tires may indicate a difference that might be experienced on the road, while smaller differences should be considered equivalent. As they say, your mileage may vary.
So, which tire type is right for you? On-/Off-Road All-Terrain or Highway All-Season? The answer depends on the most extreme driving conditions you’ll encounter, how important it is to maintain mobility in those situations, and what you have to live with everyday to have that capability when you need it.
For those considering the switch to an all-terrain tire, the advantages in off-road competence and durability trades off when driving on paved roads in the form of more tread noise, a little less responsive handling and a modest reduction in wet traction.
General Grabber AT 2 (On-/Off-Road All-Terrain): The Grabber AT 2 is General Tire’s On-/Off-Road All-Terrain light truck tire developed for pickup truck and sport utility vehicle drivers looking for exceptional traction over all terrains. The Grabber AT 2 is designed to combine long wear and reliability with year-round competence on- and off-road in dry, wet and wintry conditions. Read more.
General Grabber HTS 60 (Highway All-Season): The Grabber HTS 60 is General Tire’s Highway All-Season light truck tire developed for the drivers of crossover and sport utility vehicles, as well as pickup trucks and full-size vans. Designed to combine style, comfort, durability and performance, Grabber HTS 60 tires blend pleasant road manners, a long life and year-round all-season traction, even in light snow. Read more.
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