Fourby Fundamentals – 4WD Survival Guide

New to the off-road scene? It’s time to initiate yourself with the basics of off road adventures!

If you’re new to the world of off-road travel, things can be a little confusing, right? I mean chances
are you’ve either got yourself a new 4WD and camper trailer, or at the very least you’re entertaining
the idea of purchasing one. The thing is, there’s more to off-road travel then just hitching up and
heading off into the sunset. You’ll need to learn a few basic skills to ensure you can conquer the
offroad scene safely. With that in mind, we thought we’d give you a crash course! Yep, ladies and
gentlemen, boys and girls its time to get stuck into some offroad education!

All Wheel Drive Vs 4WD

First things first, are all four-wheel drives created equally? Well, the short answer is, no. There are
plenty of different options out there that all suit their own style of use off the beaten track. For
example, while most All Wheel Drive (AWD) SUV’s are advertised as go-anywhere touring weapons,
the reality they have their fair share of limitations for heavy offroad work. They’re usually more
acclimated for use on the black top with the occasional gravel road thrown in for good measure. It’s
the lack of ground clearance, choice of tyres and absence of low-range gearing that usually holds
them back, not to mention their lighter overall construction.

Even when you step up into a true 4×4, you’re still faced with a few different 4WD systems and
options. For example, some are part-time 4WD, which usually means they are rear wheel drive with
the option of locking in the front hubs when required. Then of course you have full time 4WD’s,
which delivers power permanently and equally to all four wheels.

When to Engage 4WD?

There’s a lot of debate around when you should lock your vehicle into 4WD. Some people believe
the further you can get up a track in 2WD the better, while the well-informed, sensible folk out there
tend to reach for the 4WD button as soon as they leave the bitumen. Why is this the preferred method? Well, first of all if you’re unable to make it through an obstacle in two-wheel drive you’ll end up digging holes, which only ends up damaging the environment and making it harder for your 4WD. So why not give your vehicle the best chance of success from the start. You’ll also notice a significant increase in handling and traction by switching to 4WD on potentially slippery surfaces early.

Popping it into 4WD could be beneficial in other scenarios too, like pulling a boat up a slippery boat
ramp, or towing a horse float across a wet paddock. It’s not all about rock hopping, eh?

Top Tip – When Not To Use 4WD!

Engaging 4WD on bitumen roads is a massive mistake for vehicles that are not full-time 4WD’s. You
see, because there is so much traction available, the tyres simply aren’t able to spin independently
or at a variable speed to one and other. This results in poor handling and stability, excessive tyre
wear and potential mechanical damage. Vehicles with full-time 4WD are typically fitted with a
differential of some kind in the transfer case to prevent these negative effects, which may need to
be activated or deactivated manually.

Understanding Gradients

Slops are typically measured in gradients. However, understanding how to interpret these figures
can take some getting used to. So, let’s take a look at how to decipher the code.
For example, if you drive forward 30 metres and at the same time rise vertically exactly 30 metres,
the gradient is 30 divided by 30, which equals 1.0, or 100% gradient.
Most 4WD’s are limited to approximately a 60% gradient, which is the equivalent to a vehicle driving
forward 50 metres and rising vertically 30 metres (30 divided by 50 = 0.60 or 60% gradient)

Stalling a 4WD

Having your engine stall mid-way through an offroad obstacle is never a nice feeling. It’s caused by either not enough power being developed by the engine to drive the vehicle through a particular obstacle under a specific circumstance, or by simply letting the clutch out too quickly or without enough engine revs. Steep hills, heavy loads or even incorrect gear selection can all be the culprit of
an engine stalling. But not all stalls are a bad thing. In fact, with a little bit of knowhow, being able to purposely stall an engine can actually be quite a useful tool to have in a four-wheel driver’s arsenal
of skills. You see, stalling your vehicle can be an effective braking method on steep or slippery
terrain. This is because when the vehicle is in gear, the engine is connected via the clutch to the
manual gearbox, differentials, wheels, and to the ground. So, if the engine stops, so does the rest of
the vehicle.
If you want to stall your vehicle while going up a hill, simply take your foot off the accelerator and
apply the brakes until the engine stalls, then turn the ignition off. To stall the engine as you’re going
down a hill, simply stop accelerating and turn the ignition off before applying the brakes until the
vehicle stops.

Hill Climbs

For steep and technical inclines, it’s important to walk the track first and come up with a plan of
attack. This way you can take the time to consider your options and calculate the best line to take. It
sure beats being forced to make rushed calculations on the way up, eh? It’s a smart idea to use
something to mark the path you wish to take, even its just mental notes of certain landmarks such as
a pile of rocks or a funny looking tree. Have a plan-B, just in case your planned line doesn’t work, and
take the time to manually build up any section of track with rocks, sticks, or stones that you think
might cause problems with traction or clearance.

The next thing is to pick a gear that will get you to the top without stalling the engine and stick with
it; changing gears manually on the way up is risky business.

Going Down

Descending a steep hill can be quite confronting to the uninitiated. The effect of gravity pushing your 4WD down can feel as though you are battling to maintain control of your vehicle, especially when it is combined with poor traction on uneven surfaces. But there are quite a few techniques available to help you keep your vehicle’s speed under lock and key, and the first of those is understanding engine braking. You see, when your foot is not on the accelerator, new fuel doesn’t get injected into a diesel engine to burn, and without fuel the engine effectively doesn’t actually run. Instead, it just draws in air, compresses it, and then pushes it out the exhaust, much like a generic air compressor. The effort required to compress this air creates a large amount of resistance inside the engine, which is then transferred through the drivetrain. The end result is the engines resistance helps maintain and control the vehicles speed on the way down. With a bit of practice, we can learn to use this “engine braking” effect to our advantage on steep declines.

Rocky Runs

As challenging as a rocky obstacle can be, they are also a heap of fun to tackle. But be warned,
they’re notorious for damaging unsuspecting vehicles. So, how do you approach a rock obstacle?
Well, for the most case moving slowly and steadily towards the first lot of rocks is the smart move.

You’ll want to be planning a driving line that provides your vehicle with the most amount of traction
and ground clearance as you go. Naturally, keeping all of your wheels on the ground is going to give
you the best chance of maintaining traction, but you also want to think carefully about how much of
an angle your vehicle will end up on when traversing larger boulders.
For scrambly climbs to the top of a rocky hill, often a bit of right footed mumbo is necessary.
However, it’s not all about pedal-to-the-metal power! Often finding a gear that has plenty of room
to move in the rev-range and keeping the engine revs nice and low (almost idling) can work
wonders. This is because the wheels aren’t constantly trying to break traction or spit the rocks out
behind you.

Beating Bull Dust

A good chunk of Australia is absolutely notorious for having bulldust. This layer of fine dust literally
covers parts of a dirt track in thick coat, which effectively hides what lies beneath. Potholes quite
literally the size of your 4WD can be disguised by a silky-smooth layer of bull dust, so it’s wise to pay
attention at all times.

The next concern with bulldust is the reduced visibility caused by a vehicle traversing over the top,
which releases fine particles that create plombs of dust in the air. It’s very nature not only blocks
your vision but has the ability to enter your vehicle through the tiniest of openings. So, it’s important
to prepare as you see an oncoming cloud of dust. This might mean pulling over to the side of the
road, winding your windows up and crossing your fingers for good luck.

Water Crossings 101

When it comes to water crossings, always check things like how deep the water is and how fast it is flowing. As a general rule, if the current is strong enough to unsettle your footing as you walked across, it will most certainly be strong enough to push your vehicle off course as well.
The next thing you will want to check is how much traction is available. For example, a bed of rocks is going to provide more traction than a layer of slop. While you’re making your assessment, pay particular attention to the exit point as well, as this can often be the slipperiest part of the crossing.
Another piece of advice is to choose a gear and stick to it. If you press the clutch mid-way through it
can allow water to get inside the clutch assembly and cause it to slip.

Approach and Departure Angles

Understanding how much clearance your 4WD has is an important part of evaluating an obstacle.
Most of us simply focus on the height of the vehicles underbody as naturally we don’t want this to bottom out. But another limiting factor is your vehicles approach and departure angle. What’s that you ask? Well, the approach angle is the angle measured between the front of the front tyre at ground level and the lowest part at the front of the vehicle. The steeper the angle, the better the clearance.

The departure angle is the same deal but reversed. So, from ground level at the back of the rear tyre
to the lowest point at the rear of the vehicle, which is usually the tow bar.

Parting Words

At the end of the day, the thought of taking your 4WD out for an adventure for the first time is both
exciting and scary, but it doesn’t have to be. If you’re looking to learn a few skills and really get
initiated with the four-wheel drive scene, it’s a good idea to get in touch with your local 4WD club.
That way you’re in the company of experienced like-minded individuals that can guide you through
the day.