Basic Off Road Driving Techniques
Many people are under the misapprehension that the 4X4 is a rough and tough vehicle which is indestructible and will take them anywhere, and irrespective of the terrain they will never get stuck, this is so far removed from reality as 4X4’s are just another vehicle which requires driving skills. This section is dedicated to those looking to learn these skills or those contemplating doing some form of off road driving; before proceeding with this section I would advocate any beginner reads the section on how four wheel drive works. 4X4’s can be vulnerable vehicles if a basic understanding of four wheel driving systems is not understood and how and when they should be deployed as considerable and very expensive damage can be done to a vehicle’s transmission, and those of us who have driven 4X4’s have all seen this.
Let us begin with a simple question, what is the slipperiest surface a normal 4X4 would drive on? Is it ice? Snow? Wet mud? No it’s none of these it’s actually wet grass, ask any farmers or an experienced caravanner who has tried to get their car and caravan out of a wet field.
Before we commence an owner needs to fully understand their vehicle and its four wheel drive operation and how everything is selected, many may have switch on the fly, and some may have permanent four wheel drive and a centre diff lock. You have to know how to select them in order to drive your vehicle effectively as once again you may do considerable damage to your vehicle if you select them incorrectly. You will need to understand the specifications of your vehicle and these will be explained:
Ground Clearance – this is the amount of underbody clearance your vehicle has, or in simple terms the largest height of rock your vehicle will pass over without damaging it.
Approach Angle – this is the maximum angle from flat ground that the front of your vehicle will approach and climb without the front of the vehicle hitting the ground and damaging it. If you move from flat ground and try to climb an uphill slope exceeding this angle you will hit the front of the vehicle on the ground and damage your vehicle, or lift your front wheels off the ground.
Departure Angle – this is the maximum angle of hill you can descend back onto flat ground without hitting the back end on the ground and damaging your vehicle.
Ramp Breakover Angle – this is the maximum angle your vehicle can travel over when leaving flat ground and moving into a descent of a hill, without hitting the underside of your vehicle. This is measured from the ground in the centre of each wheel to the underside of the vehicles lowest point exactly in the centre of both wheels.
Sideslope Angle – this is the maximum lean sideways the vehicle has before it topples, or the angle of a sideslope you can travel across.
Maximum Wading Depth – this is the maximum depth of water the vehicle manufacturer advises you wade through so you don’t flood the air intake and essentially damage your engine beyond repair.
Maximum Ascent And Descent Angles – while sounding impressive these are merely the maximum angles of hill a vehicle is designed to ascend or descend.
Many factors affect the highlighted specifications, if the suspension is compressed by weight or a vehicle travelling downhill it will reduce the ground clearance, approach angle, departure angle, and ramp Breakover angle. If the vehicle is carrying a lot of weight high inside the vehicle or on a roof rack it will reduce the sideslope angle of the vehicle due to this weight being high up, so you need to allow for these factors when off road driving and consider them at all times.
Many different terrains require different skills and it is the basics of these skills I hope people will learn, I would always advocate starting slowly in easy off road terrain and progressively working through more difficult terrain as you learn to feel your vehicle and your skills grow. You cannot buy experience, but you can learn it, so never go off road to learn without an experienced off road driver in another off road vehicle who has the kit and experience to recover you; you will get it wrong at some time, so learn from this and don’t repeat the mistakes. Many newcomers to off roading make a common mistake, they assume because others use land that they can do the same, always ensure you are on public land with vehicular rights of way, are on a private site with full permission, and are not churning up a local farmer’s field of crops. 4X4 owners are already under attack from various factions and any illegal actions such as these merely give them more ammunition and us bad press.
Before undertaking any off road driving always fully check your vehicle, ensure it is fit for off road driving and you have the basic tools and kit you may need.
Our first technique to learn is terrain reading and is something every off road driver needs to learn as if you cannot read the terrain you can end up in serious trouble and with considerable vehicle damage. Reading terrain also goes hand in hand with driving your vehicle correctly, so actually begins with road driving and requires you to have a little more knowledge of your vehicle before you begin. Two things you need to know is where your vehicles engine produces its maximum torque and where it produces its maximum brake horse power as both are needed in a range of varying terrain your vehicle can operate in. Torque is the pulling power which the vehicle will need when traversing terrain such as mud, clay, or when hill climbing as the loads on the vehicle massively increase, horse power is needed when driving on moving surfaces such as sand which you cannot stop on without sinking so need to keep moving.
Our first technique is to move up and down the gearbox smoothly by matching the changing points up or down to the engine speed without the change being jerky and the engine speed falling or rising excessively. If you don’t master this technique you can suddenly find your vehicle swapping ends on ice or snow and you’re heading backwards very rapidly into a ditch or crash barrier; to make this harder you are not allowed to use your brakes as many off road driving scenario’s do not require any braking and braking is an instinctive thing. In many off road driving scenario’s any form of braking by the driver can be disastrous and cause considerable damage to the vehicle and its occupants. Not using your brakes means reading the terrain and understanding how your vehicle can be slowed down without using its brakes comes to the fore as you need to look much further up the road or terrain than you would in normal road driving. This is where your anticipation and understanding of how your vehicle handles and reacts, and reading the terrain comes together as you will only use a controlled slowing using only your gearbox to slow down to an appropriate speed for the obstacle you are encountering. Practise this technique on a quiet road with a bend which has good visibility so you can see anything coming, or preferably, on a private road or track, then if you can, try the same thing in different terrain as different surfaces slow vehicles at different rates. One thing you will find is that you will approach an obstacle far too fast and have to use the brakes as you have to learn to balance approach speeds against distance to an obstacle and many drivers cannot do this so don’t feel badly about it. This technique means you will, with practise, look a lot further along the road and develop your anticipation, distances more accurately, and learn to feel what your vehicle is doing; it is a technique which is invaluable on or off road, particularly when driving on road on ice or snow. Basically you are learning to control yourself and your vehicle as one coherent unit. Many forms of terrain are easily read, but people don’t read them; how about as you approach a hill on a motorway? You know lorries will slow down and faster more powerful lorries will overtake them, meaning you can anticipate a lot of lorries close together in lanes 1 and 2 of the motorway. Likewise, white van man is struggling to maintain 70 MPH but you are, and you approach a downhill section, he will use this to gain speed and may overtake you, so you can anticipate this and be prepared to be overtaken and let him in, then overtake him as the road levels and his speed drops. These are all basic forms of anticipation and reading the terrain; and you will find most drivers cannot or will not do this although its common sense.
If we translate this understanding of our vehicles handling and terrain reading from road to off road terrain we find one thing will happen, you will see a problem or potential problem in plenty of time and have time to correctly react, even if this means stopping. If there is any doubt about any terrain you ALWAYS GET OUT AND WALK THE TERRAIN before driving through it, that puddle you thought was very shallow may be much deeper, or that mud patch which seems to be short may be much longer and deeper than you think, so get out and walk it first. As your skills improve you will learn to understand the look of different types of mud, clay, sand, or other loose off road surfaces.
Rutted Surfaces – if we begin with these surfaces we would normally engage 4H with the option to lock a centre diff lock if you have one fitted, this would normally apply to a loose or rutted surface which is mild, and if it worsens you can switch to 4L so you have the option. I would suggest locking your centre diff on more severe rutted tracks and you will develop the feel of when to lock the centre diff as you gain experience. Rutted tracks can cause lots of problems even though they seem easy to drive, you have to assess the depth of the ruts and ensure they won’t bottom out your vehicle and damage it, many fall victim to this issue and often it’s because the depth of the ruts vary due to many factors. You have a decision to make; do you drive in the ruts or out of the ruts? Generally I would say drive out of the ruts if you are inexperienced and the track is wide enough to do so as ruts have a propensity to make a vehicle track. Tracking is basically where a vehicle follows ruts and you cannot drive out of them irrespective of how hard you try, in many circumstances ruts can be deepened by water draining off wet land and this constantly draining water erodes and deepens them. Ruts may hold water which means decreased traction and if they suddenly deepen a combination of reduced traction and bottoming your vehicle will bring you to a sudden stop, and they can suddenly throw your vehicle to one side or the other so you lose control. Waterlogged ruts mean you cannot read them as it’s impossible to see through muddy water, so you may hit something unseen which can damage a tyre, wheel, or anything attached to them such as a front driveshaft in a vehicle with independent front suspension. Wet mud and sludge will fill your brakes so the first time you need them they will be ineffective until they have been cleaned by dabbing them a couple of times to clean and dry them.
Rutted Surface Tips – there are a few techniques for driving in runs, and more specifically getting out of them when you have slipped into them, are forced into driving in them because the track narrows, or the ground has sunk. This technique is a little disconcerting for beginners and takes practise as it throws the vehicle violently. If you have room to reverse up and get out of ruts by normal driving, then you need to, if not move forwards at speed with throttle applied, suddenly lift off the throttle and swing the steering wheel to one side quickly and violently, as its turned you hit the throttle hard, as the vehicle climbs out of the ruts you release the throttle. Another technique is called shuffling which is easily undertaken, you engage forwards or reverse gears and move in that direction until your wheels spin, when the wheels spin you dip your clutch and roll back to where you started, you then repeat this several times. Each time you move you lengthen the rut a little more and eventually it will be long enough to drive out; you need to avoid wheel spinning as this will form a series of depressions instead of lengthening the rut to the point where you can drive out of it.
Reading the terrain will give many clues as to the state of the ruts, if a section of land adjacent to the ruts is waterlogged, the ruts will be, this means the mud is deeper and it may be deeper than your ground clearance so will belly your vehicle and your wheels will be in the air spinning wildly. If the track suddenly changes it will signify a change in the ruts, if the track suddenly becomes stony or rocky it may mean any soil or other material has been washed away by natural erosion and the possibility of large vehicle damaging rocks sticking up arises, so exercise caution. Ascertaining how the ruts have formed is another skill, if it’s because of use by other 4X4’s you know they will be a similar width to your vehicle, but if it’s because of the use by agricultural vehicles they will be wider and much deeper. Tractors have wide tyres and much more underbody clearance than a 4X4 so we can reasonably conclude you will get stuck if you drive in them.
What do I do if I get stuck and cannot get out and I do not have the room to use the previously mentioned methods of driving out? You have two choices; you can be towed out by your accompanying vehicle or get out your shovel. I would advocate getting out your shovel and you basically reduce the angle of the ruts by filling them in on a gradual slope over a long length, you can use small rocks or stones, but ensure you fill in between them with something soft such as soil as this gives more traction than wet stones alone. A little physical exercise sharpens the mind and you quickly learn to read the terrain and not get stuck in the same way again, and you are leaving the track in a better condition for other users, if everyone did this many routes would not be closed so often for repairs. Much the same rules apply if you have read the terrain and found a soft of eroded spot you don’t think you can drive through, fill with rocks and stones as this lets it drain, then cover with softer soil for traction.
Snow And Ice – snow and ice are the conditions which catch the most people out as most accidents occur on the road, and as we know, most people cannot drive in such conditions and not just in 4X4’s, and we also know the roads are full of idiots. The basic rules are read the terrain ahead, but note all other road users ahead, behind, and alongside you and be prepared for anything one of these idiots may do. You have learned the skill of reading the terrain so use it!!!!! Always anticipate and judge any obstacles and avoid using your brakes, match your engine speed and change gears to slow down, and if an idiot drives too close behind you then slow down even more than necessary. If he/she rear ends you, you will be going slow enough to control the impact because it will be at a slow speed which will also minimise damage to your vehicle; he/she may overtake you which is a better option. If any idiot is in front of you he/she is in your view, and undoubtedly you will overtake them when they go into the ditch and have written off their vehicle. In ice and snow you will engage 4H and the centre diff lock if you have one, this will allow you to travel at normal road speeds, but be aware of any speed limit on your vehicle in four wheel drive as many have lower top speeds in 4H than they do in 2H, some do not. Now you have the vehicle moving as your vehicle is four wheel drive, how do you stop it? Again there are a few simple rules, you never use the brakes unless you have to, if you have correctly judged your speed and distance and slowed the vehicle right down with the gearbox it will roll to a stop. If you have to use your brakes then do so with the same gentle touch you would have with a new born baby, very gently; only apply them until you feel them begin to bite and no more, but why. With a four wheel drive you have a gearbox to brake the vehicle or just slow it down and the braking effect is evenly distributed across all four wheels; the normal braking system has a brake bias which is usually to the front wheels and biasing the braking towards the front wheels in snow and ice can easily induce a spin. This is why using the gearbox is so much better because it’s all down to balance. What about my ABS or Traction Control (if fitted) it should deal with these situations; the simple answer is that it doesn’t because ABS needs a solid surface for the wheels to grip and work properly, in snow and ice it can over brake one wheel which gives us an imbalance and a spin. Traction control works like a reverse ABS as it brakes a wheel which is spinning and puts a sudden surge of power to the opposite wheel on the same axle and forces it to virtually spin, the traction control then applies the brake to this wheel and we end up with virtually no drive on that axle due to it being braked. Contrary to what a vehicle manufacturer may tell you any ABS or Traction Control system is ineffective in snow and ice because their reaction times are too slow and their actions are often too jerky to be effective, so they are a hindrance and the best style of driving is to switch them off if possible. ABS and Traction Control is generally set for road conditions with some grip, basically they are biased towards road conditions and not mud, ice and snow, and some vehicles deactivate their ABS and Traction Control systems when the centre diff lock or low range is engaged so check your manual to confirm this. When you apply the brake in these conditions always remember it’s not a car, an average car may weigh around 1 tonne, you can easily weigh twice that, or more, and this momentum takes a lot more stopping; many people forget this and it’s the biggest cause of accidents in 4X4’s in snow and icy conditions. Never forget your weight, it quadruples (or even more) your stopping distances in these conditions.
Snow And Ice Driving Tips – always make slow and steady steering wheel movements and never make a sudden steering wheel movement as it can throw you into a skid. Read the road and anticipate, make sure you avoid using your brakes and your gear changes are smooth. If you encounter a hill you need momentum to carry you up, accelerate slowly and gently to build speed as you APPROACH the hill, never accelerate when you are on it as the wheels will lose grip and you will possibly end up sliding backwards, uncontrolled down it. Always use medium engine revs with a diesel engine vehicle and low to medium engine speeds with a petrol engine vehicle, never use high engine revs as power can come in suddenly and break your traction and throw you sideways or into a slide. Approach corners very slowly and as you turn into them you apply very gentle throttle as you reach the crown or centre of a corner and the front wheels will literally drag you out of the corner.
If you get into a skid you have options; never hit the brakes as sliding wheels have no grip, even though it’s your first instinct, turn the steering wheel so you are driving into the skid, while you lift off the throttle, then apply a little gentle throttle and turn the steering wheel slowly to turn.
Mud Driving – mud driving is one of the most varying type of off road driving there is, there is often very little steering wheel feel and in many cases turning the steering wheel actually does nothing as the vehicle keeps going forwards and does not turn, so how do we change direction. Before driving across any forms of mud we must always get out and check a few things, how deep is it, how long is the section of mud, how slippery is the mud, and is there anything such as large rocks which can damage our vehicle embedded in the mud. With mud there is always one golden rule, ALWAYS GET OUT AND WALK IT, many fall foul of this rule and get themselves stuck unnecessarily. There’s one easy way to check this, use a stick and probe the mud and see if is deep, uneven, and if there are any solid projections you have probed, if not you can proceed. You need to select 4L, centre diff lock, and the rear diff lock if you have one.
Two distinct styles of driving exist for mud; the easiest for the beginner is the constant speed method which uses a constant throttle across the mud, you never vary the throttle position even if you are slowing down. If you look like getting stuck you rock the steering wheel from side to side by a few degrees, rapidly; this ensures the front differential is working by constantly shuffling the power from side to side and actually gives traction.
Method two takes more experience and practise, this is the momentum method which means you approach at a higher speed on a higher throttle, when you hit the mud you ease off on the throttle slightly so the wheels don’t spin, then maintain a gentle throttle throughout.
Steering on mud takes a little practice as you often find you turn the steering wheel and carry on in a straight line, to change direction you simultaneously turn the wheel and give a blip of throttle, once you have changed direction you straighten the steering wheel. You will often find you cannot turn the steering wheel enough in one go to change direction; if you find yourself in this situation you turn and blip several times, basically you change direction with a series of manoeuvres instead of one manoeuvre. Very soft mud can be treated like water in many respects and all you do is drive slowly and in a controlled manner through it, never apply excessive throttle inputs at any time as your wheels will spin and you will stop. When you drive through most types of mud you will find the vehicle will drag badly, this is often you will be pushing a lot of mud out of the way with your front wheels and this is normal. For crossing most forms of mud i would suggest low range, third or second gear, never change gear when traversing muddy terrain as you can bog your vehicle down if you change up, or wheel spin and come to a stop if you change down.
Never underestimate mud as it catches out so many inexperienced drivers and a lot of experienced drivers also.
Rocky Terrain – driving rocky terrain is a skill which takes time to master the considerable variations and learn how your vehicle copes with such terrain, basically it is a very slow and totally controlled driving skill you need to master. Dry rocks can have as much grip as tarmac while wet rocks can be as slippery as ice, rocks can move and easily throw your vehicle for or aft, or side to side very easily, and any longer rocks can tip up under our vehicle and do severe damage to it, so always remember, slow and steady.
Rocky terrain always demands low range and the centre diff lock to be engaged, and first gear to be engaged to give the lowest possible speed and the highest amount of engine braking at all times, rocks can do considerable damage to tyres as many have sharp edges. Once again the golden rule is ALWAYS WALK THE TERRAIN so you can check the rocks and plan a route through. With rocky terrain the suspension always works hard, this means it is compressed on one or more wheels, and on the others it’s not, so taking suspension compression into account is a must. If our vehicle has 8.5” (215mm) of ground clearance and you drive over a rock which it would clear, but the other wheels are on other rocks and have the vehicle as an obscure angle, and one front wheel leaves a rock, that corner will have its suspension severely compressed. Often the first time you will know about it is when you hear a crunch as your vehicle’s underside hits the rock and this can do considerable damage to major components such as the engines sump, gearbox/transfer case, exhaust, or even flatten brake or fuel lines.
Rocky Terrain Driving Tips – when climbing a rock or boulder you need power, but only use as much as possible and no more, as your wheel descends you apply the brakes fairly hard, then release them just to the point where the vehicle moves forwards. Gravity is used in your favour, and you literally inch your way down off the rock or boulder, having such control means you do not hit the ground hard and compress your suspension any more than you need to, this saves your vehicle considerable damage. Road building is a skill you use with rocky terrain, if rocks and boulders are too large for your vehicle to cross, simply fill in areas between them with large rocks, then in between them with smaller stones, and then dirt, this will give you a nicer and smoother terrain to cross and reduces the likelihood of vehicle damage. If rocks and boulders are not solidly attached in the ground you can simply move them.
Ruts, Gullies And Ditches – most off road driving will involve crossing ruts, gullies, or ditches at some time, and this is where a full understanding of how your four wheel drive system works as you will always have one wheel off the ground at sometime if you cross them properly. With one wheel in the air it means that axle loses drive, so becomes ineffective and you become reliant on the other axle to continue driving you forwards, as the first axle regains grip you then rely on this axle to drive you as the former driving axle loses grip as it has a wheel out of contact with the ground. More people get this wrong as they often try to drive normally across a ditch, their front end enters the ditch and the approach/departure, and ramp Breakover angles are exceeded and the wheels become stuck in the ditch as well as the vehicles underside becoming stuck on the ground. Now you are well and truly stuck and have nowhere enough traction to get yourself out by normal driving.
Crossing ruts, gullies, and ditches requires 4L, the centre diff lock engaged if applicable, and if you have one, the rear diff lock engaged; you always use first gear and approach the ditch, rut, or gully from an angle of 45 degrees. Using this angle of approach means you only ever have one wheel flailing over the gully and the other three wheels are in contact with the ground, while you may only have one axle driving you have more vehicle stability with three wheels in contact with the ground. Slow, forward continual motion is the key to using this method, if you stop you lose momentum so the best option is to use reverse and begin again.
Ruts, Gullies And Ditch Driving Techniques – many tracks become rutted, but conditions may vary from deep mud to very soft, dry sand, so what do you do if you become stuck in a rut or ditch at an acute angle. In shallower ruts you can drive forwards (if conditions permit) and see if there is a slight ramped section where you can drive out, or the rut turns and you can build momentum and drive straight on and out of the ditch. You can shovel some debris into the ditch to form a ramp if you have a shovel, or you can make a ramp from anything handy such as small branches, and drive out. If conditions are sandy or dry dusty type conditions you can employ the same technique listed in the rutted track section. Employ 4L and lock your centre diff lock if applicable, use second or third gear and accelerate forwards at speed, suddenly release the throttle while rapidly turning the steering wheel, then apply a reasonably heavy throttle. This works by throwing the vehicle into an understeer situation as you release the throttle, when you turn your wheel this gives extra bite to the front wheel, and acceleration gives power to a biting wheel, this takes practise but is worth doing.
Hill Climbing/Descending – climbing and descending hills is one of the easiest things to do, but it goes against all the natural laws of a drivers instinct, to do this requires practise and overcoming these natural instincts. This is much more about faith in your vehicle and your ability to select the right gear to climb a hill, get it wrong and select too low a gear and you will get wheel spin, select too high a gear and you will stall the vehicle and overload the crankshaft, transmission, and the clutch. Never try to change gear while ascending or descending a hill as this involves engaging the clutch, and engaging the clutch is a definite no, no when ascending or descending any hill and you will lose control of your vehicle, hill ascending or descending relies totally on control.
To climb a hill you need to walk it first, are the approach and departure angles within the capabilities of your vehicle? What’s at the top of the hill? Is there room at the top of the hill for your vehicle, and what the ground conditions are like? It has been known for vehicles to climb a hill that has not been walked first, and it’s been a cliff edge and people have been killed by driving off them.
To begin your climb you need to go straight up the hill, never go at an angle across it, select 4L and lock your centre diff if applicable, and your rear diff lock if you have one fitted, select second or third gear and drive up with a constant throttle, don’t accelerate or decelerate while climbing. Sand dunes require a different technique, their surface is loose and moves considerably so you use 4H and gain as much speed and momentum as possible before you begin to climb, with sand you have to continually adjust your throttle as you climb to prevent wheel spin. As you crest any hill you merely reduce your throttle to stop. Never change gear while climbing, never apply excessive throttle as this induces wheel spin, and never back right off your throttle as you will lose all power and NEVER ENGAGE YOUR CLUTCH as you will suddenly roll uncontrollably backwards down a hill.
Descents are totally different to climbing a hill, always engage 4L and engage the centre diff lock if applicable, and diff lock if you have one fitted. Engage FIRST GEAR and release the clutch with NO THROTTLE applied to enter the hill and never touch either the brakes or clutch, you rely totally on engine braking for a controlled descent. If you hit the clutch you will lurch forwards totally uncontrollably, if you hit the brakes you will induce a skid which can easily throw you sideways and possibly roll your vehicle and cause considerable damage to your vehicle and any occupants.
Hill Climbing/Descents Driving Tips – if you get it wrong when climbing a hill one of two things will happen, one is you will be in too high a gear for the climb and you will stop or stall the engine, or you will be in too low a gear and you will get wheel spin and you lose momentum and stop. In both circumstances you have one option, apply the footbrake and the clutch, restart the engine and allow it a few seconds to steady its idling speed, engage reverse and release the clutch and footbrake simultaneously. This will allow the vehicle to descend the hill safely and under total control using engine braking to get you safely to the bottom so you can restart the manoeuvre using the right gear. Never use the vehicles handbrake on a steep hill as it’s not designed for this, handbrakes only work on two wheels, but the footbrake works on all four wheels, and applies much more braking force which will hold your vehicle safely.
As you descend a hill you may feel the vehicle begin to slide, this is because the combination of the vehicles weight and the angle of descent create momentum, and if the hill is slippery your tyres may not have enough traction and begin to slide because of this momentum. All you do is accelerate very gently until the wheels are moving at the same speed as the vehicle and it has regained traction, gently ease off the throttle and you will descend in a controlled manner.
When descending any hill the natural instinct is to brakes, always place both feet flat on the floor of your vehicle so you resist the urge to apply the brake or clutch. With a petrol engine vehicle you may find that on steep hills the engines revs rise excessively and the engine won’t hold the vehicle; petrol engines lack the torque of diesel engines so you need to use the brakes, only apply them until they just bite and maintain them there so the engine revs drop VERY slowly. One other method to use is cadence braking; cadence braking is a technique where you pump the brakes on and off very quickly, the problem with cadence braking on a hill is that it makes the vehicles wheels slide so is best avoided in preference to a very gentle braking.
Sand Driving – this is a unique surface due to the nature of sand, it moves, offers little traction, and if you stop on dry sand your vehicle will often just sink up to its floor. Unlike all other driving techniques previously mentioned which use low speed, torque, and total control; sand relies purely on speed, momentum, and pure engine power at high engine revs and continual movement so you don’t stop on it and sink. One expert described sand perfectly when he said it was water skiing in a vehicle, you need enough speed to skim across the surface and if you don’t have enough speed you drown, this perfectly sums up sand driving. When you drive on sand you will find it has more drag than any other surface and it will sap engine power quicker than any other surface you will drive and put more strain on your transmission than any other surface, and dry sand is so abrasive that it can cause more wear on a vehicle than any other surface.
Sand comes in two distinct types, these are the dry sand which sap power and cause a vehicle to quickly sink; and the wet sand which is slightly easier to drive on as it is more compact than dry sand and saps less power and offers more traction as it is more compact.
When driving on sand it is preferable to build up speed before you hit the sand so a solid surface is used to build up speed before you hit the sand, as you hit the sand the drag will often mean you must be prepared to quickly drop a gear to maintain high engine speeds. With sand you accelerate extremely gently and change gears to build speed as you drive across it, but you must make smooth and rapid gear changes so you don’t lose speed or momentum. Steering on sand can be difficult, never use large steering movements as turning the front wheels will increase the drag on the vehicle and slow it down as they dig into the sand, always make very wide turns with the minimum steering angles. When driving on sand you always use 4H and lock the centre diff if applicable, and the rear axle diff lock of you have one fitted; maximum traction is the key to moving effectively across sand as there is often so little traction available. Crossing sand is best done with another person so you can walk the proposed route, always ensure you have an entrance and exit and leave the other person at the exit so they can prevent other vehicles blocking it so you have a direct route across the sand and can get off it. Driving on beaches uses a slightly different technique as the wet sand is generally firmer near the sea due to the compacting action of the sea; drive across the dry sand to the wet sand, drive as close to the sea as possible without hitting the water.
Sand Driving Tips – sand driving requires a large amount of kit to be carried and is always best done with at least two people in each vehicle, and more than one vehicle which have the appropriate equipment for the conditions. Always carry a couple of shovels as any stuck vehicle will be sinking, often faster than you can dig it out, four long pieces of carpet are handy to put under the wheels of a stranded vehicle to allow it to get moving, and some string to tie the carpet to the back bumper so you can drag them without stopping. If you get stuck you can use the rocking method to try to get going before the vehicle sinks, alternatively you can dig some long tapering trenches in front of the wheels to allow you to get moving again, but you have to be quick and do this before the vehicle sinks.
Water Driving – driving across water is a technique reserved for the more experienced driver, but the techniques will be listed for the novice, beginner, or less experienced off road driver so they understand the techniques if they encounter any deeper water. Before you even consider driving across water you need to understand your vehicle, you need to locate the engines air inlet as many vehicles have them mounted very low on the vehicle, even the best known off road vehicles, which surprises many people. This knowledge is essential as air compresses and water does not; if you get water into your engine it will become “hydrauliced” and trashed, this will require a replacement engine so should be avoided at all costs, and this will obviously mean the vehicle will be stranded in water which could potentially deepen. Never drive in water deeper than the manufacturers recommended depth and if your air inlet is mounted low down always disconnect it and let the vehicle pick up air from under the bonnet. While you’re under the bonnet and you have electric fans you need to pull the fuses out which control them so they are disabled and will not cut in and spray water all over the engine and drown it.
Before crossing any water you need to gauge its actual depth, water is always deeper than it looks so check its depth all the way across your proposed route, check you have an entry and exit which is suitable, and then get your socks and shoes off as its time to get wet. Walk the proposed crossing route and check the bottom for everything from rocks and depressions and solidity, the bed of the water may hold a 15 stone person but not 2.5 tonnes of off road vehicle; so these checks are vital. Any rocks can throw the vehicle sideways and dip one side into the water, likewise any depression can tip the vehicle sideways and both these can fill the engine with water and “hydraulic” the engine, and a soft bottom will give no traction and you will be stranded.
Basically; there are two types of water and these are static water which would be found in a pond or lake, and moving water such as that found in a stream or river. Moving water exerts massive forces and if you stand in it you will feel the force on the small area of your legs, now imagine what force that will exert on the side of a vehicle with its much larger surface area; water can easily move a vehicle sideways and push it down stream. One simple rule applies, if the water will not pass under the vehicle then do not cross it, discretion is the best course of action so avoid this condition and find a better crossing point where moving water will pass under the vehicles sills and not come up the side of the vehicle.
Crossing water has one simple rule, slowly; always use 4L and first gear, and engage the centre diff lock if applicable and a rear diff lock if you have one. Always use the lowest engine speed possible to prevent engine driven or viscous fans from spraying water everywhere as they would with higher engine speeds and keep moving at all times so water does not enter the exhaust, and never stop the engine. If you stop the engine water can enter the exhaust pipe, as the engine cools down it can suck water up the exhaust and into the engine and destroy it when you try to start the engine again. Engine speeds should be around the 1000-1500 RPM range.
Many people find it entertaining to drive through water as fast as possible and spray it everywhere, this is stupid and should be avoided as if there is more drag on one side of the vehicle it can lurch sideways and out of control, and many have found this out the hard way and written off their vehicles. Such actions can fill the engine compartment with water and this is to be avoided as it can fill components such as the alternator, electrics, electronics, and the air inlet with water; it can also create problems for drive belts and cause them to slip and if you suddenly lose your power steering it’s dangerous. In some circumstances with deeper water the front protection plates can ski, this is where they skim across the water and hold the front steering wheels off the ground and again you’ve lost steering. In many circumstances you can splash pedestrians or others in the vicinity of your spray and this is illegal and the Police have prosecuted many people for doing this. And obviously there are the realities of environmental damage which cast us all in a bad light with numerous anti 4X4 groups. Such actions give the anti’s and local authorities the ammunition to close the few remaining off road routes we have.
Notes For Automatics – while most of this article applies to both types of transmission, automatics sometimes require a little modification to the driving style as many do not work in the same way as a manual transmission, but automatics are often seen as better for off road work.
When ascending or descending hills always lock the transmission in one gear, many auto’s will have the facility to lock it in one or more gears, it might have the positions 1, 2, and D (drive), or it may have the facility for tiptronic functions which hold it in a fixed gear until you change it. If you do not have this function you will have to cadence brake to ensure the auto does not change up a gear while descending a steep hill.
Automatic gearboxes can be poor in snow and ice, so always use four wheel drive when driving in these conditions as they have torque multiplication which can spin a rear wheel drive vehicle which it will have if it’s in 2H and not 4H.
When driving in muddy conditions, always clean the auto box as they run very hot and a build up of debris can cause it to overheat its transmission fluid very quickly, this in turn will wear out the clutches and that is expensive; a simple hosing is all that’s required to remove any mud.
If driving in water always ensure you fully dry your automatic box by driving for around 20 miles with a hot engine, some transmission fluids mix quite well with water and this mixture will ruin your delicate internals of an automatic box. Any tiny amounts of water entering your gearbox will be boiled off with the heat of the transmission fluid and keep it in good condition.
Follow the basic rules, begin slowly and steadily and understand your vehicle, try different driving techniques as vehicles vary from manufacturer to manufacturer, and begin learning the different driving techniques gently and advance as your skills progress.
Assassin
Thu Jan 26, 2012 4:22 am
