4WD: Rock and roll a bad combination
Rock crawling isn't just for comp trucks performing impossible contortions at extreme angles as suspension systems, tyres and drivelines are pushed to the limits.
There's a huge array of aftermarket equipment to improve your vehicle's rock-crawling ability on tougher tracks. But remember, manufacturers spend millions compromising between off-road capability and on-road drivability. Generally speaking, a brilliant rock crawler doesn't have great on-road manners or may put you offside with the law or your insurance company, so think twice before heavily modifying the family transport.
Mechanical modifications to drivelines and suspensions, or running larger-diameter tyres improves your vehicle's ability to deal with bigger obstacles. You also need appropriate skills to read the terrain, pick the right line keeping the vehicle level for the best clearance and traction.
Surveying an unknown pathway through rocks and boulders via the windscreen is the quickest way to come undone. Hidden obstacles, sudden drop-offs or sharper-than-expected ledges can quickly catch the ill-prepared driver. Stop. Get out and walk difficult tracks first, even if you do have someone spotting the line ahead. If necessary, move some rocks and do some road building to minimise the risk of damage to your vehicle, add traction and give yourself a better line.
Check your vehicle's ground clearance - note the diff location, spring and shocky mounts and any vulnerable areas you need to avoid scraping.
Follow the simple approach of as fast as necessary but as slow as possible. As a guide, use second gear low range for climbing, and first gear low range for descents (locking your foot away from the clutch if a manual). Don't change gears during the descent. Allow the engine to do the majority of the braking with the occasional gentle feathering of the brake pedal if needed. Always engage hill descent control, if fitted.
Lowering tyre pressure improves traction and can reduce potential punctures by allowing the rubber to mould itself to the terrain. How low depends on the vehicle and the size and type of tyre fitted. Remember, for every psi you let out, the overall volume remaining in the tyre reduces exponentially. Lower pressures require lower speeds, trying to avoid any sudden swerves.
No matter how tempting a short cut, never drive on a slope sideways as the potential for vehicle rollover is extreme. Keep your thumbs outside the steering wheel (more critical on older vehicles) and push your accelerator foot against the kick panel to avoid rapid throttle movement over obstacles thereby reducing wheel spin and the vehicle surging.
If your first attempt fails, stop re-evaluate and try a slightly different line. Simply adding more speed and aggression will almost always end in tears. If you're not comfortable, don't do it.
But with the right techniques, rock crawling can be a challenging and rewarding test of vehicle and driver.
