A ship in harbour is safe, but that is not what ships are built for. 4X4s are adventure machines. From the ground up they’re designed to take us out of our comfort zones, beyond the horizon to places never before seen. Across rocks? Certainly! But let’s do it in a way that doesn’t cause damage to your vehicle.
Unfortunately the vast majority of off-roaders put more stock in the modifications made to their vehicles than working on the skillsets to take on those situations. Rock driving is one of those challenges that can throw a spanner in the works for new and old 4WDers alike. Arming yourself with the figurative tools to take on rock driving ensures your adventures don’t end when the easy trails do.
Know your 4X4
You can make the first step toward ruling the rocks before even leaving the dealership. In rocky terrain the first thing to catch you out will be low-hanging components. Spend 10 minutes lying underneath your vehicle to get acquainted with the driveline. The key areas to look for are driveshafts, transfer case, diff centres, fuel tanks; and suspension components like arms and leaf spring mounts. Imagine you were trying to drive over a basketball-sized boulder and how you’d need to steer your vehicle to miss all the low-hanging components. That’s Step one to line selection.
Get the right gear
That new twin spare tyre carrier you’ve been eyeing off might be just the thing your 4X4 needs, but in the rocks you have to factor in the negative aspects of fitting one up. You’ll never need good approach and departure angles anywhere like you’ll need them in the rocks. A step 500mm off the ground is easily drive-able for most 2-in lifted 4X4s, until you start adding bulbous bar work and low-hanging bash plates that’ll have you punting metal (not tyres) into the rocks. Adding scrub bars, sliders and front and rear bars may be vital to prevent panel damage. However, be careful you’re not making your 4X4 less capable in the process.
Know the terrain
There are two types of rock you’ll encounter in the bush. Either dry rock or slick rock. The actual geological names are impressive, but irrelevant from the driver’s seat.
Dry rock is a high-traction surface. Spinning your wheels isn’t going to find you any more traction, and can only end in tears. Slick, or wet, rock will provide very little traction and will often leave you reaching for the winch. Both types of rock should be taken as fast as necessary and as slow as possible.
Drop your pressures
By now the myth of dropping tyre pressures to widen the footprint should be more or less gone. The tape measure has proved once and for all that lowering pressures drastically increases the length, not the width, of your contact patch.
By increasing the surface area of the tyre we’re able to spread the load of the 4X4 out over a larger area, reducing the likelihood of digging in; and vastly improve the traction available with a sturdier grip on the terrain.
In the rocks, dropping pressures also allows the tyres to conform to the uneven terrain. This allows them to mould themselves around the obstacles you’re driving over. It’s the difference between bumping into a rock, or completely wrapping it in tyre-rubber for maximum traction.
Walk the line
With the vehicle prepared it’s time to face the obstacle itself and perform what we call ‘the aeroplane’. With your arms out to each side, your hands will be roughly the same width apart as your wheels. This allows you to visualise where you want each tyre to go, where you need to steer, and what you need to avoid.
Where possible you’ll want to avoid gnarly side angles, although in some situations they can be required to keep your vulnerable sheet metal away from the rocks. With multiple ledges, now is the time to do a little track building so you’re not trying to climb two ledges at once.
Second pair of eyes
In anything difficult enough to have you walking the line, a second pair of eyes from a spotter will be invaluable. They can ensure you’re staying exactly where you had planned to be; as well as spot any issues that may come up throughout the drive.
Before setting off, agree on a set of simple and easy-to-see hand signals. Then make sure to ignore every other yahoo trying to tell you what to do. One spotter. One line of communication for the driver. No distractions.
Reach for the lockers
In an ideal world, rock driving would be like climbing a set of stairs: Smooth ledge after smooth ledge. In the real world, rock ledges are rarely square with each other. This means you’ll often find yourself either lifting a wheel, or climbing an obstacle with one tyre on it and the other spinning.
On high-traction surfaces, wheel-spin is the devil. Therefore, you’ll want both lockers engaged to keep it to a minimum. And you’ll need to be in low-range first gear for maximum torque and climbing ability. In many situations, traction control is a huge benefit. Although when the going gets really tough it rarely allows the crawling speeds capable with twin lockers (instead functioning like an advanced version of ‘riding the brakes’ when you lift a wheel).
Know what breaks, and how to avoid it
The two major killers of components you’ll find in the rocks come from pushing your vehicle’s drivetrain beyond its comfort zone. CV joints are normally the first to go. You’ll find the further from straight they are, the weaker they become. Front locker on, full lock on the steering and a bootfull of loud pedal will destroy just about any CV joint in an instant. If you’re steering full lock, keep the locker off if possible. Also be sure to go smooth on the throttle.
Drivetrain shock from bouncing and wheel-spin is another sure-fire killer of drivetrain components. The huge shock load can destroy diff gears, uni joints and axles. If you start bouncing, back off the throttle instantly and reassess your line.
Call it quits
You could spend the next 100 years on YouTube and not find one single hilarious video of a driver accepting they’re not making it up a climb and reaching for the winch. Conversely, it only takes about half a second to find a few hundred videos of drivers who didn’t know when to call it quits. You’ll see it resulted in snapped axle shafts, punched-in sheet metal and insulting comments from those who reckon they know better. But let’s face it, they rarely do.
The point is there’s no shame in winching through an obstacle and heading on your way; but there is inevitable remorse in letting bravado get the better of you to the point where your 4X4 is severely damaged. Play stupid games, win stupid prizes.
Instead of turning around and abandoning the track when you see rocks ahead, remember these tips. Keep in mind what we said earlier “A ship in harbour is safe, but that is not what ships are built for.”
