Just How Slick Is Slickrock?
Slickrock is actually sandstone, and it's one of the best surfaces for traction you can find off-road. The term slickrock derives from its smooth surface and rolling curves. Over the course of centuries, ancient sand has been compressed into stone with a surface texture similar to 100- to 120-grit sandpaper. What could offer better traction than that? You'll quickly find that you'll be able to drive on steeper hills than would be possible on almost any other surface.
This will hold true right up until the moment slickrock gets wet. Water is a great lubricant, and once it hits Moab's beautiful red rock, it does a great job of greasing your wheels. So, when it rains, use caution and stay off the steep slopes. Rain and snow will not only greatly reduce traction, but will also wash all the loose dirt and sand off the face of the slickrock. When driving after it rains, even weeks after in some cases, watch the terrain ahead of you. Try to avoid the pools of water and mud. If the trail forces you to get your tires wet, remember to drive a while and dry your tires before attempting anything steep.
All-Terrains Or Mud-Terrains?
The simple answer to this question lies in the fact that on slickrock, the keys to traction are more rubber and softer compounds. All things being equal, a softer tire will grip better than a hard one. The same is true when comparing the treads on mud-terrain and all-terrain tires. All-terrain tires put more rubber in contact with the slickrock. While the massive lugs of a mud-terrain are a big plus in mud and can even claw their way over sharp rocks, the thick tread blocks don't flex as much on slickrock as the smaller tread blocks of an all-terrain tire, and as a result, can slip more easily.
How Low Should You Go?
For most rigs coming to Moab, tire pressure should fall somewhere in the 16- to 18-pound range. This will provide plenty of sidewall flex and should keep the tires seated on the beads. With bead-lock wheels, of course, you can run your tires at pressures as low as 8 pounds. Naturally, these pressures are only recommendations, and your actual needs will depend on your vehicle's weight, the type of trail you're going to be running, and your driving style. Weight is an important factor when airing down because heavy rigs require more tire pressure than light ones.
Another consideration when airing down is your tire's sidewall aspect ratio. A 37-inch tire on a 15-inch wheel has more sidewall than one on a 17-inch wheel. The greater amount of sidewall provides more flex and wobble, especially at lower pressures. Also, a tall sidewall has more leverage to pop the bead than a short one. If you have tall tires on small-diameter wheels, you'll want to run higher tire pressures.
Because of the traction you get when driving on slickrock, you'll find that it affects your steering. It can feel similar to driving on pavement with four-wheel drive still engaged. Hard steering is more of a problem when you're running lower tire pressures, have a front locker, or are driving down a steep hill and need to turn. Stock 4x4s will allow you to run in 2WD, 4-Hi, and 4-Lo. If you find that steering is particularly difficult at a tight point in the trail, you can disengage your locker (if it's air or electric), or try turning the wheel slightly forward or backward while moving. If you're not in a particularly steep area, you can try driving the trail in 2WD.
The phenomenal traction can also give you a false sense of security when it comes to side hills or steep ascents and descents. If you're unfamiliar with where you're headed, take it easy and don't let the thrill of the trail lure you into trouble. Look ahead and make sure you know where the trail is taking you.
Rules Of The Road
Every year, four-wheelers lose a few more roads and trails in the Moab area. It's not always fair, but that's the way it is. One of the best things you can do to help prevent this is to four-wheel responsibly. Stay on the trail. Many of the trails are now clearly marked with signs. Don't be tempted to try new routes or obstacles. Go over bumps, not around them. After all, that's what you're here for. Just as important, pack out what you pack in. If you see litter on the trail, stop and pick it up. If you spill any fluids - coolant, oil, and so on - take a minute to mop it up.
Just as important as taking care of the land is taking care of yourself. Try not to travel alone. Bring plenty of water, and remember that even during Easter Jeep Safari week, you're a long way from help if something goes wrong.
Trail Ratings Deciphered
2 Unimproved or rarely graded road; four-wheel-drive or extra clearance needed at times, with no special driving skills required
2+ Road seldom graded; four-wheel drive, good clearance, and low gears often needed, with some extra care and a bit of driving experience useful
3 Road in difficult terrain; expect some erosion damage, repaired barely enough for passage; four-wheel drive, good clearance, and low gears essential
3+ Road in difficult terrain; expect to drag front, rear, or middle occasionally; excellent stock truck or utility vehicle required, with considerable driving skill needed
3++ Not quite a Category 4, but the trail is too challenging for stock vehicles
4 Road in difficult terrain with considerable erosion damage that is repaired only enough to get well-equipped vehicles through; modifications for improved off-highway performance and top driving skills needed
4+ Like a Category 4, but more so; low gears, tall tires, and limber suspensions required, with limited-slip or locking differentials strongly recommended; common to have as many as 10 percent of the vehicles experience major mechanical failures (gears, axles, driveshafts) on these trails
5 Locking differentials and toe hooks, front and rear, necessary; winch highly recommended, unless you have a really good buddy who is sure to be in position to help you with his winch