Tires are round and black-what else do you really need to know? That depends on what you want from your tires. If your only concern is to roll down the road, you're pretty much done. But we're betting you'd like to have more traction in the loose stuff, perhaps some sidewall protection from trail debris, and some insight into why there are hundreds of supposed off-road tires. Most importantly, you'd probably like some help figuring out which tire is right for you and the way you use your vehicle.
Tires are often the first thing to get changed on a 4x4. That's because tires can completely change the performance of your vehicle, and the appearance too. Larger tires give your ride more ground clearance for better four-wheeling, and the tread and construction of the tire can make a night-and-day difference in motoring through soft sand, driving through sloppy mud and traction on wet pavement. The next few pages will act as a primer on tire technology and selection. Next month, we'll address wheels, since they are often upgraded at the same time.
Tread Pattern
This is what most people judge off-road tires by, and rightfully so. A super-aggressive tread pattern delivers the promise that this tire will fling mud and sand, and grab rocks like a skilled rock-climber. It's also one of the key visuals that sets your 4x4 apart from a stocker in the parking lot. To give you a quick comparative look at some of the most common treads on the market today, we have grouped 10 treads, side by side. (See "Footprints" on page 62 for these images and a bit of information about each of the tires.)
For our purposes, there are five basic groups of tread design: Street, all-terrain, extreme all-terrain, mud-terrain and rockcrawler. You'll sometimes hear about mud and snow tires (or M&S), but that just means it meets the Rubber Manufacturers Association guideline for this designation. And while these guidelines might have meaning for snow and the type of mud that oozes across the road once in awhile, it's not a good measurement of what we're looking for in a mud-terrain.
 Siping is the process of cutting...  Siping is the process of cutting very small grooves, or "sipes," into the tread blocks. This gives the each block of tread additional gripping surfaces, which is noticeable on wet and icy pavement, the ability to channel water on a micro level and an additional way to dissipate heat. Siping can give tires such as this Goodyear DuraTrac better on-road performance without losing any off-road performance that larger tire lugs and tread-block spacing provides. |  Some tires have tread patterns...  Some tires have tread patterns that were engineered to work really well in a specific direction. This is typical of very high-performance street performance tires and extreme off-road tires. Directional tires often give you the best grip on pavement, water channeling and mud/dirt/sand traction, but you can generally expect a bit shorter life because these tires can only be rotated front to rear. Directional tires, such as this Pro Comp Xterrain, will be clearly marked on the sidewall. | |
Street tread is designed for maximum traction on pavement and good tread life, period. These are the tires you might choose for your wife's Tahoe, but they don't offer advantages for any off-pavement use. Because of that, we have not included any of them in this article.
All-terrain tires cover a broad range of tread types, and are a great compromise for general-purpose use. These perform well on pavement and deliver moderate performance off-road as well. The tread is generally an interlocking design with more voids than a street tread. All-terrain tires also almost always feature siping, or very small grooves cut into each tread block, for better grip on smooth surfaces and ice. This type of 4x4 tire offers good tread life, a quiet ride and very good on-road handling characteristics. These are a great choice for a vehicle that you use primarily on road, but want a bit more capability for occasional use off-road. The BFGoodrich All-Terrain T/AKO is the iconic tire in this segment, being introduced in 1976 and enjoying a healthy market share over its life. Other current examples include the Goodyear Wrangler SilentArmor, General Grabber AT2 and Pro Comp Radial All-Terrain.
The rules for all-terrain...
The rules for all-terrain tires are changing dramatically, and companies are pushing the limits of off-pavement capabilities while retaining the on-road manners that most all-terrain customers really want. A little more spacing in the tread blocks and more aggressive shoulder lugs give this new breed of all-terrain tires much better performance in mud, rock and sand, but the basic tread design and layout provide good on-road traction. In addition to the Pro Comp Xterrain A/T shown, this new in-between style of tire also includes Goodyear DuraTrac and Mickey Thompson Baja ATZ Radial.
There is also a new category of hybrid tires-offering on-road manners and handling closer to an all-terrain tire and providing more grip than a typical all-terrain with more aggressive side lugs and larger voids between these side lugs. Examples of these tires are the Mickey Thompson Baja ATZ Radial, Goodyear Wrangler DuraTrac, and Pro Comp Xtreme All Terrain Radial. These tires are perfect when you really want more off-pavement performance than a traditional all-terrain can offer, but you want as much on-road traction and minimal road noise. They also look cooler than an all-terrain tire. This might be the perfect choice for a 4x4 tow vehicle.
Mud-terrain tires have been the standard tire for off-road performance for decades. And they still provide the best all-around performance off-pavement with larger lugs and more space between tread blocks to grab a lot of terrain. The larger voids let the tires clean out easily with a little bit of wheel spin. Generally, they don't perform as well on-road compared to a street tread or all-terrain, and the tread life is isn't as long, but you're running these tires for what they do for you in the dirty stuff. Examples of tires with this tread design are the BFGoodrich Mud-Terrain T/AKM2, Goodyear Wrangler MT/R with Kevlar, Mickey Thompson Baja MTZ Radial, Toyo Open Country MT and Pro Comp Xtreme Mud Terrain Radial.
Rockcrawling tires have evolved in less than 10 years as the rockcrawling sport has grown. The BFGoodrich Krawler T/AKX was the first tire on the market for this group of extreme wheelers who only cared about traction for rock crawling. So the attributes of this segment are massive lugs with extreme spacing, puncture-resistant sidewalls, and very soft rubber compound. The Krawler continues to focus on rockcrawling performance, while the Mickey Thompson Baja Claw Radial and Pro Comp Xterrain Radial also have aggressive tread patterns, but offer good performance in mud and on pavement as well.
Footprints
 BFGoodrich All-Terrain T/AKO... BFGoodrich All-Terrain T/AKO
* 30 years recognized as a true on- and off-pavement tire
* ShoulderLock technology, upper sidewall traction bars
* High-void all-terrain tread design
* Siping and a stabilized tread center
|  BFGoodrich Mud-Terrain T/AKM2...  BFGoodrich Mud-Terrain T/AKM2
* Krawler-inspired tread design
* Linear flex zones for conformity when aired down
* Large and thick sidewall lugs
* TriGard sidewall construction
|  BFGoodrich Krawler T/AKX ...  BFGoodrich Krawler T/AKX
* Deep lugs
* Soft rubber compound
* 4-ply sidewall construction
* Large sidewall lugs
* Wheel protection
|
 Goodyear Wrangler SilentArmor...  Goodyear Wrangler SilentArmor
* 50,000-mile tread life warranty
* Kevlar layer for toughness
* Reduced road noise
* Durawall sidewall technology
* Wheel protection
|  Goodyear Wrangler DuraTrac...  Goodyear Wrangler DuraTrac
* TractiveGroove technology for better traction in mud and snow
* Self-cleaning shoulder blocks
* Highly angled center tread blocks for better on-road traction
* Wheel protection
|  Goodyear Wrangler MT/R with...  Goodyear Wrangler MT/R with Kevlar
* DuPont Kevlar reinforced sidewalls
* Wraparound tread for added sidewall traction off-pavement
* Aggressive, asymmetrical tread patter for off-pavement traction and on-road handling
* Advanced silica rubber for better off-road and wet traction
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