Normally at this time of the year I would not wander about on muddy tracks, as I prefer to follow the “Tread Lightly” Policy. Fortunately around my local forest there are numerous sustainable routes. However, with this topic in mind, today I made an exception and so I checked out a normally solid track that I know does rut up when the forestry vehicles use it for access. I wasn’t disappointed!
This content was developed by and owned by Paul Sinkinson, Xplorability owner. Paul is a 4wd Defensive Driver Training Consultant/Trainer and Programme Developer.
Ninety per cent of this particular track was in good condition despite the torrential rain of the past week but three areas had suffered. The first was a relatively long and steep descent, the second the ascent opposite and the third, a flatter area that was the entrance/exit for the track.
This part of the track is sandstone rock/gravel perhaps 800 meters long with the main part elevated above the grass side. After the hot summer months, dust and or dry mud/soil has layered the surface, which, after the recent rain and forestry traffic has now taken on something similar to the consistency of a “Slippery Yogurt!”
With the laws of gravity dictating that water runs downhill, all of the ruts, dips and hollows on the track fill up with it and the rest either runs off the sides to the grass areas or collects at the base of the slope. Descending in these conditions can be tricky and perhaps not for the feint hearted. It is very easy to lose control, slide out of the ruts and finish up sideways to the slope. This is NOT fun and could lead to a rollover in certain circumstances.
It’s now time to remember the training material posted on the Training page that covers the use of Hill Descent Control (HDC) with your Discovery 2 (or other models or makes fitted with a similar system).
Engage LOW RANGE – Engage Centre Diff-Lock if installed – Press the HDC Yellow Button on the Dash Panel and ensure that the GREEN Light is showing on the top left of the instrument panel - Engage a suitable gear, normally 1st gear for descents although because you are using HDC you could engage 2nd Gear as, if you do not touch the throttle or the brake pedal, the HDC will engage at speeds circa 6 to 8 mph. Drive as straight as possible down the hill and preferably stay in the main ruts as they act line Tram or Railway Lines and should keep you from sliding sideways. Don’t get crossed on the ruts.
REMEMBER - Allow the HDC to control the descent DO NOT BRAKE OR ACCELERATE or it will disengage. All you have to do is to steer a straight passage. At times you WILL be tempted to drive out of the ruts and you may even decide to accelerate to do this but IF YOU DO the HDC will Disengage. Your Tyre Treads will by now start to look like this – THEY WILL BE FULL OF MUD! They will slip and you will slide. Without HDC engaged you may lose control.
If you do lose control you are likely to slide off the raised area of the track onto the side banking which are usually sloped to drain water away. These are usually boggy ground and if you slide sideways to the base you may either rollover or become trapped in the mud and require recovery.
This photograph is of the vehicle just off the main track on the edge of the grass drainage slope. For obvious reasons it has not been driven further down it to avoid becoming bogged in
Following the “Basic” Hill descent techniques and using your HDC System should take you safely to the base of these slippery hills and slopes.
Quite often, Forest tracks are undulating following the land contours and so having descended a hill you may find yourself having to make an ascent directly opposite.
In the hollow at the base before the new ascent you usually find that water has drained to that level both from the hill you have driven down and the one you are faced with driving up. The track therefore at that point could be boggy and or if reasonably solid it may have puddles of water.
Leave the HDC Engaged! This is in case you fail the ascent.
You are now about to ascend the hill possibly having to drive through either the mud or standing water at the base. It’s a good idea to get out and just inspect the ground before you start. The reason for that is because IF it is Boggy you may need to accelerate through the mud and continue straight up the hill at a steady pace to maintain traction as your tyre tread will be full of mud which makes it more difficult.
If you are “LUCKY” and the ground is reasonably hard with standing water, you may benefit from driving back and forth in the standing water to clear as much mud from the tyre treads as you can to aid traction for the climb.
Driving back and forth through standing water can clear tyre treads and aid traction – Before and After photos
Once the decision has been made, choose the most suitable gear for the ascent. Usually this is 2nd Gear (although if using an automatic you can select D3 as the vehicle will start in 1st, change into 2nd should the revs be suitable and should you have wheel- spin it may even change to 3rd smoothly which could aid traction although the Traction Control (TC) may do that anyway). With a Manual vehicle, choose the gear and stay in it as if you try and change UP or Down you will lose momentum and fail the climb. On a slippery hill this can be “Exciting!”
You have kept the HDC engaged for this very reason and should you fail the ascent use the Failed Ascent Techniques advised in earlier posts. Here’s a photograph taken on the same track back in 2005 during a training exercise for a newly formed French 4wd Club. The main flat area of the track was dry BUT the side grass areas were still wet and boggy and it was necessary to use my Discovery 2 to extract the “non-believers” who found that out the hard way. They learned their lesson.
Learning the hard way about waterlogged side slopes
Further along the track following this dry area, the next ascent was somewhat different. After only light rain, all the “New” club members, Defenders and Discoveries came to understand the difficulties of ascending long steep greasy slopes. You can see that even the more experienced of these three drivers in the D90 and the D110 were crabbing sideways while the pure “Novice,” new to off-roading that very day followed the theory training given to him a few hours earlier and out drove his colleagues. Knowledge is the KEY!
Standard Discovery with a novice driver still out driving the more experienced drivers in their Defenders
Well, you’ve had the excitement. You’ve driven a steep descent, cleared the base and then driven the ascent and you’ve been successful on both counts. NOW is not the time to get cocky! You still have to exit the track and that too could be messy. Now is the time to remember the information on Traction Control (TC) and Momentum.
As “Slow as possible and as Fast as necessary.”
Time for Home now – REMEMBER, your tyre treads will be mud filled and this could cause loss of control or skids on the Black Top roads. You will also leave mud on the roads so perhaps try driving on flat grass to clear this before you hit the tarmac so you are not causing a hazard to other users.
When the day is finished pressure wash all the mud off your vehicle and get it ready for your next trip out!
When ground conditions are firm and dry, straddling wheel ruts is acceptable to maintain ground clearance.
When ground conditions are soft and slippery put wheels in ruts to avoid excessive ground damage and to aid in directional stability.
Appreciate vehicle ground clearances, especially under differentials.
Use spade to chip centre of track into ruts to aid clearance. If necessary Fill ruts with available material. IE: foliage, rock etc.
Never straddle ruts on a steep ascent or descent as this may result in loss of directional control
When driving a rutted track if the vehicle wheels finish crossed over across the track at an angle to the direction of travel do not stop, try and keep moving forward or you may become blocked
Be aware of where your wheels are as when muddy it is easy to have the wheels locked over
If the tyres get a grip on the rut side the vehicle will immediately move in that direction which may put you in danger
This photograph was during a summer of “Bull Dust” and “Dry Soil” which had turned into an extremely slippery surface and with the steep descent even with front, rear and centre differential locks every vehicle came to slide almost uncontrollably to the extent that some chose the safety of dropping wheels into the side ditch rather than slideoff the track over a 100 metre drop.
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This content was prepared for the Off-Road Discovery Website by Xplorability 4wd Training
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