GUIDELINES TO SPECIFIC OFF-ROAD DRIVING SITUATIONS
As mentioned before, driving off-road can be a lot of fun but it needs experience and care. Often damage is done to new 4x4's or to the environment because drivers don't follow the basic rules for off-road driving. In order to enjoy off-road driving it is important to learn the basic rules. Once you've learned them, all it takes is practice.
STEEP SLOPES
DECENDING A SLEEP SLOPE
- Engine braking is the best tool for descents. By using the compression of the engine to slow your M-Class down, all wheels are braked simultaneously which eliminates the risk of the wheels locking.
- Engage Low Range (at standstill) and first gear.
- Always descend in a straight line to avoid slipping sideways.
- Braking on a steep slope may lock the wheels and result in sliding out of control. If engine braking is not sufficient, apply the brakes gently. Do so in short jabs to avoid locking the wheels. Only brake when the M-Class is moving in a straight line.
- If the M-Class starts sliding, steer towards the direction of the slide and apply a gentle, careful acceleration and then steer out of the side.
SLEEP ASCENT OR HILL
- Never drive up an ascent a slant angle as this could cause your M-Class to roll over. Always climb along the line of the gradient.
- Don't stop in front of the slope. Stabilise your speed before you start to climb.
- If your attempt to reach the top fails due to lack of power, select a lower gear and try again, alternatively select to drive up in reverse. If your attempt failed due to lack of power start your ascent at a safe higher speed.
- To prevent your M-Class from suddenly driving too fast after cresting the gradient, slightly release the accelerator just before reaching the crest and use only the momentum of the M-Class.
- If the incline is too extreme, never try to turn your M-Class because of the danger of tipping. Instead drive slowly backwards in reverse gear along the line of the gradient.
THE "STALL START"
- If your engine stalls on a steep incline, stay calm.
- Apply the foot operated parking brake firmly while holding your M-Class with the brake pedal.
- Low Range must be selected (if not already selected).
- Select reverse immediately after starting the vehicle.
- Release the foot operated parking brake. Let your M-Class roll back against compression, applying the brakes only if you start descending too fast.
SAND / BEACHES
SAND DRIVING
- Reduce tyre pressure as this increases the flotation area of the tyres. 100 kPa (1 bar) should be sufficient, but in extreme conditions you can go as low as 80 kPa (0.8 bar).Remember to return the tyre pressure to normal after negotiating the sand obstacles.
WARNING: Do not reduce tyre pressure unless you are equipped to inflate the tyres back to normal recommended pressures. Driving with deflated tyres over extended periods will cause tyre damage.- Select Drive.
- If you get stuck, try reversing along the same tracks you came in. On your second attempt, go through with a little more speed.
- When you need to stop, simply slow down and let your M-Class come to a halt. Don't touch the brakes! Applying the brakes will cause a weight shift and a little wall of sand to build up in front of the wheels.
BEACH DRIVING
Recently, regulations have been proposed to prohibit the operation and use of any vehicle in South Africa's coastal zones. The regulations only provide for limited exemptions such as scientific research.
- Where allowed, driving should be done below the high water mark.
- Like for sand driving, reduce the tyre pressure.
- An outgoing tide is the safest time to drive on the beach because it gives you extra time to dig yourself out in case you get in trouble.
- Drive as close as possible to the water's edge, but avoid splashing into it.
CROSSING WATER
Avoid water if possible, at all times, especially salt water because of the corrosive effect. Attempts to go through water is one of most common reason for damage to 4x4's.
- If you are forced to go through deep water, walk the obstacle to check the depth and strength of flow. If the flow is too powerful to walk against, driving through it will be very dangerous.
- Check the vehicle manufacturer's specification data sheet or the M-Class handbook for the maximum wading depth.
- Do not wear a seatbelt in deep water. -Ensure that the engine air intake is kept clear of the water.
- Slow speed is essential and low range second gear is recommended for most wading conditions. Enter the water slowly and avoid creating a splash that could cause a bow wave. Do not brake.
- Never come to a halt in water, and never shut off the engine.
- After negotiating a stream or river crossing, ensure that the brakes are dry. You can dry the brakes by driving a short distance while lightly applying brakes.
MUD DRIVING
Try to avoid driving through deep mud! Rocks and logs often lie hidden under the mud.
- Select the appropriate gear before negotiating the mud. The lower the gear the more likely it is that the wheels will start spinning.
- Try to keep your speed constant.
- A way to aid traction is to swing the steering wheel from side to side while driving. The extra traction is given by the side walls of the tyres as they move through the mud.
- Apply brakes only when absolutely necessary.
V-SHAPED GULLY
- Driving through V-shaped gullies should be done with extreme caution as steering up one or the other of the gully walls, could lead to your M-Class being trapped with it's side against the gully wall.
- When a V-shaped gully is entered, it should be done at an angle so that only one wheel at a time is dropped into it. The same should be done when exiting.
ROCKY TERRAIN
- Evaluate rocky obstacles and terrain before attempting to cross them with your M-Class.
- Know where your M-Class' lowest points are. -Select low range and first gear.
- As slow as possible let your M-Class "walk" over rocks. Gain height placing a wheel on a rock instead of straddling it.
- WARNING: You will damage your M-Class if you drive fast and irresponsible over rocky terrain.
TOWING OFF-ROAD
When pulling a trailer keep in mind, that the forces exerted by a trailer off-road are similar to those on-road but they are amplified! A trailer reduces maneuverability off-road. Instability and control problems can even occur at very low speeds.
- Disconnect the jockey wheel and stow it before the ground gets rough.
- Disengage the over-run brakes (where applicable) by sliding the lock over the towing arm, to prevent it from retracting and engaging the brakes. When driving, allowance rarely needs to be made for the trailer's ground clearance as in most cases it exceeds the vehicle's.
- Make allowances for the additional weight when braking and descending steeps slopes by braking gently and changing to low gears timeously.
- If in the case of lost steering control while descending steep slippery slopes, gentle acceleration fails to pull the trailer straight or if acceleration is too risky in terms of losing control of the vehicle, then the only way out may be to disconnect the trailer. Then manhandle it down the slope or seek alternative solutions.
- We would like to remind you at this point that tow bars are designed and fitted for towing trailer and must not be used for vehicle recovery.
© DaimlerChrysler South Africa, 2001. All rights reserved. Click here to view the disclaimer.
