[tsk1979]

Yes, on dirt tracks no issue as there is enough slippage.
but remember, not to exceed 60kmph in 4WD on any surface. The hubs can get damaged.
I think the manual lists 80kmph as top speed in 4WD advised, but to be on the safe side, stick to below 60.

[SS-Traveller]

Originally Posted by tsk1979

SS, I suggest you attempt rohtang pass, and get caught behind a slow moving truck etc., you will find rpms dropping to 1200(as the truck lumbers on at 10kmph)

The routine I use in such situations (so do truckers) is to back off a bit, wait till some space opens up, and then go up at a higher rpm. In any case, even at Rohtang, I don't think there are hard-tarmac steep-slope sharp-hairpin sections (most parts are at least gravelly, if not dirt track on these routes - enough for wheel spin and windup release).

Originally Posted by suman

...I can't figure why anyone would half clutch in a 4wd vehicle - what's the purpose of engaging the 4wd then? You engage, you release the clutch & then you go. It defeats the entire purpose if you half clutch, doesn't it?
EDIT: In your Rohtang example, you can engage 4H & go along without stalling.

Errr... why would anyone half-clutch in any vehicle at all?? If I had to keep my foot on the clutch for more than say, 30 sec, I'd say I'm doing something wrong.

Originally Posted by vardhan.harsh

So i take it from the conversation that it's NOT advisable to do U-turns with 4H/4L engaged on tarmac.
However it is ok to do U-turn in 4H/4L modes on dirt-tracks. Correct?

On gravelly or sandy tarmac, why not? If you're really paranoid, carry some KY Jelly, apply it to the tyres, then do a U-turn on hard tarmac.

[suman]

Originally Posted by tsk1979

At rohtang some stretches are so steep that if you let rpm come below 1200 or so, vehicle can't pick up.
It stalls.
So either you rev to 2000rpm with clutch pressed, start releasing clutch, and start climbing or engage 4L and then easily climb. I do the latter.

Luckily, I have not faced a stalling situation in Rohtang. Where I've felt its steep, I have engaged 4H on the fly & blasted up at higher rpm. As I mentioned, at particularly nasty patches, I have engaged 4L. Now, talking about traffic jams, trucks etc is a different scenario.

Remember, the entire discussion (which has now been incorrectly moved to this "Off Road Driving Techniques" thread IMHO) started off with Harsh asking if it was OK to engage 4H for steep tarmac slopes over a short distance. He gave an example where there were no trucks, no dirt, nothing - just a steep tarmac slope. I reiterate that it is OK.

Originally Posted by SS-Traveller

Errr... why would anyone half-clutch in any vehicle at all??

I agree but up in the mountains, quite a few of the 2wd Sumos, Taveras & Scorpios rely on half clutching, building up the revs & the momentum to get them through some of the water crossings etc

[Jaggu]

4H on tramac is ok if its for brief period and slow speeds, but unless its slippery i dont think it will really make a hell lot of difference wrt climbing. On the other hand 4L would really help to climb out of tricky situation on tarmac, but use it at very low speeds only, but that would be the case if you are crawling like Tsk faces. IMHO.

[suman]

Originally Posted by Jaggu

On the other hand 4L would really help to climb out of tricky situation on (al;thoughtarmac, but use it at very low speeds only, but that would be the case if you are crawling like Tsk faces. IMHO.

I'm sure it would be. But I would be wary of using 4L only if I'm going uphill behind truck traffic on Rohtang with hairpins all the way.

Mind you, I'm an absolute newbie as far as hardcore off-roading is concerned. I'm sure you have statistics in terms of what difference 4H does or doesn't make climbing uphill so I'll bow to your experience (even though I felt an actual difference myself & put it down to additional traction & that's more or less what Arka also confirmed).

As far as 4L getting one out of tricky situations, no one is disputing that. As I mentioned somewhere, I have used 4L myself at tricky places in Rohtang....and Zoji La. Mentioned here & in my travelogue.

[Jaggu]

I think we both talking same thing, yes 4H in slippery surface helps. But if its non slippery but steep incline it might not really help, it will rather zap power due to transmission loss to all 4 wheels. But as soon as a slip happens 4H will score away.

[gunnerbala]

Well having Driven Jeeps, Gypsies, 4WD 7Tonners and 8x8 TATRAs in both Heavy Snow and Loose Sand Dunes totally x-country,,, for quite some time,, the one thing I follow is - Never Lose Momentum. The only rider that goes along with that is - Dont Overspeed,, you'll have hell to pay later!! LOL! Keep up the good work guys!

[Velmurugan]

Quite agree with the last post.Momentum is your friend & Speed is your enemy. Both go hand in hand.The trick is the right balance between thw two & apply it. This will come by experience, involvement, driving with awareness!

[Sudarshan]

^^^ I remember some Land Rover training documentary ( produced in 60s may be , looked much older ) , they suggested -- as Fast as necessary & as slow as possible .

The vehicle shown were ordinary ( non modded ) Land Rovers , but those were doing quite well .

Sudarshan

[binu balan]

Few techniques I have learnt and practiced during my Army days:

Whether you are new to the sport or an old trail hand, remember that driver experience wins out over vehicular modifications in most situations . An experienced driver will recognize what terrain is beyond the limits of his vehicle and know when to call it quits (this is the reason we used to have the experienced drivers do the rekki and guide the rest). Knowing how to use throttle, gravity and inertia is also important and often makes the difference between getting through a bad section or getting stuck and needing a tow. The key is not to overdo it, but to use these variables to your advantage. Different types of terrain often require somewhat different techniques, so we've separated this Story into sections that deal with what you may come up against and where. And just for good Measure, we've included a section to cover the basics that apply to most off-road adventures, and what you need to safely overcome even the roughest obstacles.
The Basics:
Seatbelts - Put on your seatbelt, and instruct passengers to put them on as well. A good belt will help restrain you when driving difficult terrain, and can save your life in case of a rollover or other accident. Some people want to jump clear if a vehicle rolls, but it usually rolls on you and kills you. Don't try it. (Seatbelts will help you stay in position in your seat and help you stay in control)
Locking Hubs/Transfer Case - The first thing to do when you get in the dirt is to put the transfer case in Four-Wheel drive and lock the hubs - if your vehicle is so equipped. With all four wheels hooked together, your control is increased, braking is improved, and you won't get stuck as fast when you make a mistake. This also spreads the tractive force over four tires instead of two, minimizing breakage of drivetrain parts. However, with practice, flipping back and forth between 2wd and 4wd can be advantageous for turning, sliding, and other advanced maneuvers, but it's best to learn while in four-wheel drive. Using low range in the transfer case is an asset that many beginners forget. In low range the available power is greater, and the speed with which you can drive is diminished. By driving slowly over obstacles rather than pretending you're in a SUV commercial and flying over them, you're more likely to make it to the other side instead of breaking your rig or yourself. Going downhill is also easier in low range, as compression braking from the engine is increased. This allows you to stay off the brake more often for optimum control.
Watch - Watch the driver in front of you and see how he/she makes it through. You can learn allot on what to do and what not to do. Get out and walk the trail or examine the obstacles before you drive through. This allows to get a mental picture of where you will place your tires before you go. Walk ahead and look back; the view is different from the other direction, and other features of the terrain become apparent.
Thumps Up! - Make sure that your thumbs are not wrapped around it. If the wheel should suddenly whip around from a tire hitting a rock, your thumbs won't get broken or mangled. With power steering fitted to most 4Wdrives these days, this technique is not as critical as the power steering unit dampens out sudden steering wheel movements. Owners of non-power steering vehicles will have undoubtedly experienced at some time the force at which the steering wheel turns when hitting an obstruction.
Diff Position
It is important to know the position of your front and rear differentials as they are usually the lowest ground clearance point of your vehicle. Similarly, any other low ground clearance points should be noted e.g. exhaust, spare tyre etc. When a large rock or other obstacle is on a track that you must drive over, you should ensure you avoid driving directly over it with the lowest ground clearance point of your vehicle.
Braking
When using the vehicle’s brakes hard, your vehicle’s front suspension compresses and you 'use up' most of its suspension travel, When braking sharply to avoid an obstacle e.g. pot hole or rut, and you cannot stop in time, release the brake pedal just prior to hitting the obstacle. This will allow the front suspension to return to its normal height and give more suspension travel when hitting the obstacle.
Vehicle Limitations
A four wheel drive vehicle cannot be treated like a normal car when cornering. The 4WD will roll over much easier than a car while cornering if they are taken too fast, because it has a higher centre of gravity. This applies to gravel and bitumen roads equally. Although a four wheel drive vehicle generally has better traction on gravel than a car, when safe cornering speeds are exceeded the four wheel drive will tend to roll earlier than a car
Keep silent - Turn the stereo off so you can hear what your vehicle is telling you. The sounds of slipping tires, scraping metal, and engine RPM can all help you be a better driver, but not if you can't hear them. Distractions from what is happening from our vehicle can distract you at the wrong time.
Know Your Vehicle - Know where all your controls are in the cab and what hangs down underneath.
Clutch - Staying off the clutch unless you need it is important in many situations. While automatic-equipped 4x4s can have an easier time crawling over things, a manual transmission rig is capable of outdoing an auto as long as the clutch isn't always used. Try driving with your feet on the floor for practice, and see what your rig can do. Once you push in the clutch you've unhooked the drivetrain, and only your brakes will be holding you on a hill.
Tire Pressure - Consider lowering your tire pressure according to the terrain and speed. Tire pressure lower than the manufacturer's recommendations can provide greater tire traction, flexibility, flotation, and smoother ride. Because the tire will tend to spread out at lower pressures, a bigger footprint is formed, but the tire is susceptible to sidewall damage. Never air down farther than what you are comfortable with, and remember to air back up to specs when you hit the pavement.
Spotting - If you're unsure of what you're doing while driving an obstacle, ask someone to spot you over the tough areas. An experienced spotter can be your best ally and can make you look like a pro. Remember, though, that you as the driver are the one in command, and it's your decision to trust the spotter or not.

(I had got most these info from a web site about 8years ago)

The Basic Guide to Winching Techniques

http://www.pirate4x4.com/tech/billav...o_winching.pdf

[SPIKE ARRESTOR]

^^ Binu, during your army days, which vehicles did you use? Jeep or Gypsy, curious to know.

Spike

[binu balan]

Spike- For daily use it was the King. Jonga and the 550. How ever I have had the privilege to drive vivid vehicles, like the Shaktiman, Nissan 1tonner, Kraz 6X6 a Russian giant truck, Czech Tatra 8X8, the Swedish Scania and Tank Schilka.

[binu balan]

Few off road videos:

v=ioLwXHfF6ys&feature=related"]

YouTube - ‪Hard off road Bins.3GP‬‏

YouTube - ‪Off road non diff lock.3GP‬‏

YouTube - ‪off road Babs.3GP‬‏

YouTube - ‪Off road 90 deg climb.3GP‬‏

[Baburajs]

This was real fun off roading using only one jeep. I will do a write up on this when I have time. This is a great track very close to Bangalore for may be for 5 to 7 vehicles.

Babu

[smsrini]

Mods: I could not find a thread on this topic, and hence have started a new one. please merge if one already exists.

I found a very good write up on the topic of Offroad driving techniques and thought I'd share with the rest of the community.

Source: A Guide to Off-Road Driving

1) Read your owners manual thoroughly before going off-road, or on road for that matter. Learn your vehicle.

2) Never go out alone. A short venture could be costly. One thing we try to stress during our Off-Road Training classes is that you should never venture
off the highway alone, even more so in the cars of today. With all that electrical fun and games bolts on here and there, you’d have a very slim chance of
driving out should a major problem occur. Remember the western bound pioneers? Do you have any idea as to how long it took them to cover ten miles?
How about the hardships involved? Lack of water? Lack of shelter? Poor clothing? Have you thought of these things? NO?
Just think, what if... You are ten miles off the main paved road, your 4WD quits, possibly you have an accident, now what? Your cel-phone doesn’t work,
no one in sight, do you sit tight? Walk out? Something to consider, isn’t it? Okay, so you walk, do you have the right shoes? Clothing for when it gets
cold at night? Water? Well? Lots of questions, but few answers. One can’t foresee everything that could go wrong, and shouldn’t try either.
Being prepared yourself and having your vehicle prepared and maintained to a reasonable degree will help counter some problems. Taking along another car
is a smart thing to do, chances are both cars won’t quit while out. The second car could surely tow out the first, or go for help if necessary.


3) Always make sure your vehicle is prepared before departing.

4) Adopt a relaxed and upright driving position with a loose grip on the steering wheel, taking note to keep your thumbs out of the center section of the
wheel, thus avoiding broken thumbs from steering wheel kick-back. This is a common problem on vehicles not equipped with power assisted steering.

5) Contact between your right foot and the gearbox tunnel will help increase throttle control. The use of a "dead-pedal" on the left is also helpful.
DO NOT use the clutch pedal as a "dead -pedal". Once the clutch is engaged (out), keep your foot clear.

6) Know your minimum ground clearance. On vehicles equipped with liveot; axles (fixed), the minimum ground clearance is the lowest point of the axle housing, normally the differential. This minimum clearance always remains the same as the axle goes up/down with the wheels. To obtain your minimum clearance, measure from the differential housing (its lowest point) to the ground, there it is, your minimum ground clearance. The minimum won’t change, though maximum can when a wheel climbs up.

Attachment 579491

The Live axle always maintains its minimum ground clearance (arrows left).

6A) On vehicles fitted with independent suspension however, the front wheels are attached to the A-arms which go up/down independently from each other, at the same time the center portion of the chassis/suspension goes up/down as well, though the exact opposite of the wheels. Type of terrain, as well as braking can effect your ground clearance dramatically; when the front wheels are bottomed on their suspension points (up in the fenders as far as they can go), your chassis and front suspension pivot points are now very vulnerable to damage as they come closer to the obstacle. It is a proven fact, that for heavy duty off-road work vehicles fitted with live axles are preferred.

Attachment 579492 Attachment 579493

As you can see from above, the ground clearance varies as the suspension moves up/down. Left: In its unloaded position you could have 8 (example), while Right: In its bottomed position it could reduce to half. Always be aware of vehicle ground clearance and obstacles.

7) Suspension & Wheel Travel. Since the time man first developed wheeled vehicles his thought must have been on smoothing the ride. Leaf springs have been
around since what must be the beginning of time. Horse drawn wagons, buggies and the famed stage coaches had leaf springs. The leaf spring has two advantages
over any other form of suspension, in that a) it’s cheap to produce, and b) they will carry heavy loads. A number of today’s 4wds are still built with leaf
springs (on a HD pickup its understandable), while others have gone the Coil spring route. Coil springs do allow heavy carrying capacities to an extent
while offering a smoother ride and better wheel travel/articulation (movement up/down & angle of axle). Other manufactures have sought to create car like
rides on their 4WD vehicles by fitting independent front suspension, either torsion bar or coil sprung, though neither of which is in its element when
off-road. The best set up? Coil sprung/Live axles; this set up offers smooth ride with extreme rates of wheel travel (wheel movement up/down) and is still
cost effective to build. Independent front suspension, as described in #6A, is expensive, car like, and offers little to the off-roader, as it can be
damaged easier than a live axle, has more pieces to maintain/damage, and can not offer the wheel travel and stability when off-road.


8) Know your Approach angle, Break-over and Departure angle (Below). Knowing these figures (i.e.: Clearance), you’ll be able to negotiate obstacles much easier without damage to your vehicle.

Attachment 579494

Interested in learning what these figures are on your vehicle? Try a long broom stick. Placing it under the edge of the tire, then lifting up until it makes contact with the body, you now have some idea of your angles. When off-road, drive up to your obstacle lowly, then stop get out and look to check clearances upon approach. When clearing the obstacle, be careful to walk the rear wheels off, remembering always that most 4WD vehicles have some sort of overhang beyond the rear axle (when walking your 4x4, the use of brakes, a spotter and your own sight
will enable you to creep the rear wheels off the obstacle). Damage will result if care is not taken. As far as break-over is concerned, also know as
high-centered, this too will take a keen eye, the assistance of a spotter, and practice.



9) Know your vehicles height and width. Think about parking garages and parking spaces, will your 4WD clear the obstructions within the structure?
Now apply the same to overhanging trees, narrow washes and rocks. Easy really.

10) Check the area(s) in which you plan to travel off-road. Ask locals about conditions. Purchase and review local maps. And... When in doubt, get out and take a brief walk to review the terrain ahead. This walk could save hours of digging and/or winching, or the anguish of having your new 4WD damaged.

11) Be aware of changing weather conditions, the last thing you want is to get caught on the desert floor. When in doubt head for high ground (when heavy rains come in), and get out of the washes or off the desert floors. Beware of fast running water... if you can’t swim it, don’t drive into it.
Many vehicles have been lost in rough weather and water. Beware!

12) Know your Four-wheel-drive system. Unlike days gone by, the systems of today vary in their modes of operations and capabilities. Review your owners manual or talk with an expert concerning your vehicle make. Don’t assume anything.

13) Engage Low-Range before you need it. Choose the correct gear for the situation, see #12. Note: On vehicles fitted with a manual center Diff-Lock,
this should be disengaged once traction has been regained. However, Low-Range should be kept engaged until clear of the hazardous area(s). FYI: This center
differential-lock is just that, a lock, locking the front & rear drive outputs of the transfercase together. When unlocked (disengaged) it will prevent
"axle windup" with in the drivetrain. Vehicles fitted with a standard High-Low/2wd-4wd system have no center-differential, and when engaged in 4WD for long periods they will induce axle windup. You may notice that in tight turns while in 4WD that the front wheels will seem to hop and buck, this is the windup trying to escape from the system. Don’t be alarmed.

14) Before entering a difficult section, make your choice of gear selection. Remember that you should ALWAYS use lst gear (First, Low-Range) on down-hills for maximum engine braking effect, and keep the use of brakes to an absolute minimum, the use of which could cause sliding and loss of control. To correct a sliding vehicle, turn into the slide and apply some throttle, you will now have to straighten the steering wheel and let off the throttle. Gear selection for up-hill use depends on the make of vehicle, though 2nd or 3rd would be a good place to start. Choosing too high a gear can lug or stall an engine, keep you eye on the tach. Using steady rev’s of 1800-2200 rpm is a good starting point.

15) If conditions are soft (marshy ground, sand, etc.) it may be advisable to lower tire pressures. This helps improve traction, and will reduce sinking.
Tires will have to be re-inflated for road use.