Driving Skill: Master Terrain in your 4WD
Backcountry exploring can be a rewarding venture. Your 4WD can get you to remote places to access that secluded camping spot, that secret fishing hole, or your favorite trail to wheel down. Knowing the abilities and limitations of your vehicle, along with your driving skills will make those outings more enjoyable. In most cases, driver skill can be your most important tool, regardless of what you drive.
Every vehicle may best tackle an obstacle differently based on its wheelbase, tire size, tire track, ground clearance, overall weight, and other factors. Learn the lines on which your vehicle works well and don’t always expect to tackle an obstacle in the same way as a different vehicle in front of you. Short-wheelbase vehicles are typically less stable, but can turn in tight spaces. By contrast, a long-wheelbase vehicle usually offers increased stability, but you have to plan further ahead and tackle tight turns differently than you would in a short-wheelbase 4WD.
If you drive a manual transmission, do your best to keep your foot off the clutch. Use low gears to creep forward, saving yourself from slipping the clutch in a higher gear. Learn the two-foot technique where you operate the gas pedal with your right foot while simultaneously feathering the brake with your left foot as needed. With an auto transmission, this can help engage the torque converter to move your rig forward, without attaining excessive speed in a spot where you want to crawl slower.
A larger tire footprint generally translates to greater traction. We’re surprised by how many drivers take their 4WDs in the backcountry yet never adjust their tire pressure. Most tires on standard wheels can easily handle pressures of 15-18 psi (or lower) off-road without a tire coming off the wheel bead. Tires vary and you can experiment with what pressures work best with your vehicle weight and terrain. With beadlock wheels, you can dip to single digit inflation pressures for maximum traction.
Here we’ll discuss techniques to tackle a variety of terrain and offer tips for each scenario to help improve your driving skills.
Ascents
Hill climbing is generally a big part of off-road ventures, and the nature of the trail surface can add to the challenge of getting to the top. Short hills can be less of an obstacle, and you may use momentum as needed. It’s generally the long hills that can be the most challenging and sometimes no amount of momentum or speed going into the hill is going to sustain you until you reach the top if you don’t pick your lines skillfully.
On those long hills, first ask yourself what you’ll do if you don’t make it all the way. Can you back down safely? A little forethought here can be prudent. Carry momentum and use steady throttle for the most part. Sometimes backing off the throttle to reduce tire spin will afford you greater traction when climbing really loose hills. Once you do make it to the top, take care to know where you’re headed next or what’s over the blind crest at the top.
Descents
If you get in trouble bouncing up a hill, you can often stop forward motion and sit on the slope to rethink your attempt. However, when making steep descents, sometimes gravity wants to keep pulling you to the bottom even though you’d like to stop and reassess the situation.
Learn to use the compression braking of your engine. By placing the transfer case in low range and/or placing the transmission in a low gear, you can better control your descent down hills without using the brakes heavily and locking them up. Learning to counter-steer can be a useful driving skill when you find yourself loosing traction and sliding down a steep hill. Look to the bottom of the hill to see that the area is clear and you have a planned route down.
Off-Camber
Driving off-camber is probably the most daunting position for most wheelers when it comes to the point of feeling like you’ll tip right over. Traversing deep ruts or side-hilling can place a lot of weight on the downhill side of the vehicle, leaving the uphill side light. Bouncing around in this position can exaggerate weight transfer, so resist jerky movements if you’re in this situation.
When dropping a tire in a hole or ravine that causes the vehicle to tilt off-camber, the natural tendency is to want to steer back away from that low spot. However, knowing the proper driving skill of turning the lowside tire back uphill tucks it more under the vehicle providing less tire base for stability. Steering the face of the tire downhill presents more rubber to the ground to the downhill side, often increasing stability. This is especially true when you’re straddling a ditch and have a firm bank on the downhill side to steer into.
Sand
Once you start to dig into sand, it’s often best to stop right there. Most places where you encounter soft sand are washes, dunes, or beaches, and the sand is essentially bottomless. At that dig point, you often can’t accelerate your way out, but instead further dig your tires deeper into the grains. Sand is the perfect place to run with aired-down tires.
Be especially weary of beaches where the water level changes. Sand patches exposed during low tide can be deceiving, and you don’t want to be caught stuck there when the tide rolls back in. Damp sand usually packs well and provides solid traction, but mixed with a little more water it starts to get slushy and unstable. Desert wash sand can often be decomposed granite or similar material. Even with it dry, you can dig in quickly with excessive tire spin.
Mud
Ah, mud! Fun to play in, but a chore to clean. Mud comes in many flavors and consistency. Soupy water with dirt and sand stirred is much different than thick brown fluid. Aggressive mud tires are designed to shed mud as the tires rotate to gain a fresh bite as they turn back into the goo. Know that if you’re running all-terrain tires, and you’re following your buddy with mud-terrains, you’ll most likely need more speed and momentum to cross the same patch he does.
There are two realities when dealing with mud. With mud of limited depth, the technique may be to claw through the gooey stuff to firmer ground, assuming you have a tall enough tire. When mud is essentially bottomless, or too deep for your tires to reach bottom, you’ll need momentum and speed to skate across the muddy surface before you sink too deep in any one spot. This may only work for short distances, as you lose speed and need to find drier ground again. In either situation, careful modulation of the throttle will help you find that sweet spot between moving too slow and spinning and digging too fast.
Snow
Like mud, snow comes in many consistencies from dry, fluffy flakes to cold slush. Obviously, icy surfaces offer little or no traction. In contrast, untouched snow can offer good traction as it crunches under your front tires. Lowered tire pressure and throttle variation will help you decide the wheel speed that affords you the best traction forward.
When busting new tracks into fresh deep snow, it may be necessary to push forward by backing up and following your tracks forward aggressively into the snow, making a little movement further each time. Somewhat like mud, progress in snow can depend on depth. In deep snow, you’re pushing a bank with the front of your vehicle and the leading edge of your tires.
Rocks
When running trails, traversing rocks is best done at a slow, steady pace. Too much throttle can throw you off your line or possibly destroy parts. When presented with a boulder field, a lot of beginners tend to want to snake through large rocks or put them between their tires hoping to prevent high-centering on the axles. However, many times it’s best to simply drive the tires on one side of the vehicle over rocks, despite pitching the vehicle off-camber. Wet rocks can increase the challenge and may require a bit more wheelspeed to traverse.
It’s inevitable when playing in rocks that you’ll bump your differential from time to time. Many factory differential covers are relatively weak and may dent if pounded too hard on a rock. This can result in the cover rubbing on the spinning ring gear and may eventually lead to a hole worn in the cover. Bump boulders gently or consider armoring these areas for greater protection. Lowered tire pressure increases traction in rocks as the tires flex to conform to the surface. Utilizing driving skill and knowhow over boulders and in rocky terrain can make the difference between getting to the campsite or having a major repair on your hands.
Water Crossings
Splashing through the wet stuff on the trail is often fun, but water can be deceptive and quickly disastrous to your vehicle. Learn where and at what height your engine air intake lies to ensure water does not enter there. When you cross water of considerable depth, you start pushing a wake of water in front of you. It’s usually best to keep moving consistently to the dry ground on the other side. Cross downstream rather than upstream to minimize the wake pushing into the front of your rig. When in doubt, stop and check water depth before crossing.
It’s best to make crossings as quick as reasonably possible. Stopping in deep water for an extended period allows water a greater chance of finding its way past your axle oil seals and into lubricated areas where it shouldn’t be. Also, stirred up water can hold sand and tiny pebbles in suspension that can work their way into your brake components, especially inside brake drums. If you haven’t already done so, consider adding extended axle vent lines that terminate higher than the deepest water you expect to encounter.
[divider]Ten Things to Avoid[/divider]
- Surprises – Don’t drive too fast or move forward blindly. Use a spotter when needed.
- Overloading your vehicle – Reduce the chance of parts breakage and improve stability.
- Going out unprepared – Carry some basic tools, spares and fluids. Learn to use them.
- Digging your vehicle deeper – Know when more throttle is futile and it’s time to reassess.
- Locking up brakes going downhill – Learn to maintain feathering control on steep descents.
- Mounting gear too high – Tires or heavy gear on roof racks raises your center-of-gravity.
- Flash floods – Watch for rainfall dangers when exploring washes or other low areas.
- Getting completely lost – Carry maps, communication gear, and have a backup plan.
- Hammering the throttle too hard – Parts can and will break leaving you to field repair.
- Thinking lots of cool hardware can replace driver technique – Practice and learn.
Editor’s Note: A version of this article first appeared in the Winter 2015 print issue of Tread Magazine.
