First off-roading with Grand Vitara

[Alfa_Kilo]

Originally Posted by tsk1979

your limited knowledge is correct. Just one doubt. So when central diff is locked, the front right will rotate at same speed as rear right and ditto for left, right?
Suppose you get stuck where the front left is free and rear right is free.
So when the front left wants to freewheel, it is locked with rear left, hence you retain traction....?
Little confused.

No.
With the central diff locked, the vehicle is configured like a traditional 4x4 with a transfer case engaged. This means that the front and rear drive shafts are locked together, the wheels at the axles are still free to exchange speed between them. One will require locks at each diff to ensure that all wheels move in unison. LSDs help somewhat, but they are not the answer for proper off-roaders.

[tsk1979]

Originally Posted by Alfa_Kilo

No.
With the central diff locked, the vehicle is configured like a traditional 4x4 with a transfer case engaged. This means that the front and rear drive shafts are locked together, the wheels at the axles are still free to exchange speed between them. One will require locks at each diff to ensure that all wheels move in unison. LSDs help somewhat, but they are not the answer for proper off-roaders.

Ok, now I understand. In the video posted, they guy engages 4L and still you have 2 wheels spinning madly, and 2 wheels slowly rotating(limited slip working here I guess).

[headers]

Originally Posted by tsk1979

Considering the slope and lack of slush, a 2WD can make do if the driver is experienced. AWD definitely.
The real test of off road is slush where the wheels sink in.
Other test is riverbed with round stones. Thats almost impossible even with 4WD, you definitely need diff locks.
But do not try those stunts while running in.
I think your paddy field adventure was more off road than this one.

You dont need difflocks tsk..What you need to do is to keep the momemtum consistent if in motion already..the start and stop have to be very gentle..No wheelspins.

And nothing happens to these vehicles even while running in..Its only the high rpms that are to be avoided..especially for a long time..Guess he's not doing 5000 rpm..

Offroading is more on the driver skills if on a difficult terrain..most 4x4 vehicles have the basics i.e a tranfer case with low gear that multiplies the torque!

[Samurai]

Originally Posted by headers

You dont need difflocks tsk..What you need to do is to keep the momemtum consistent if in motion already..the start and stop have to be very gentle..No wheelspins.

Offroading is more on the driver skills if on a difficult terrain..most 4x4 vehicles have the basics i.e a tranfer case with low gear that multiplies the torque!

I fully agree, especially after the 4x4 training experience in Kelambakkam. The Jeep I drove had no diff locks, just 4WD with LSD. The real trick was in keeping the momentum steady, avoid wheel spin, avoid over-revving, listen to the engine, know how to recover when stuck, and constantly plan your path through the terrain. I never felt the need for diff locks although I was driving through very rocky trail with full of boulders. In fact full diff locks would have been a problem here since it would mess with the turnings, I constantly needed to turn the wheel. The diff locks may help in the mud, but in rocky terrain I couldn't see how it helps.

[headers]

Originally Posted by Samurai

I fully agree, especially after the 4x4 training experience in Kelambakkam. The Jeep I drove had no diff locks, just 4WD with LSD. The real trick was in keeping the momentum steady, avoid wheel spin, avoid over-revving, listen to the engine, know how to recover when stuck, and constantly plan your path through the terrain. I never felt the need for diff locks although I was driving through very rocky trail with full of boulders. In fact full diff locks would have been a problem here since it would mess with the turnings, I constantly needed to turn the wheel. The diff locks may help in the mud, but in rocky terrain I couldn't see how it helps.

The diff locks help when 1 wheel is in the air and the other wheel is on ground.. Normally with vehicles without difflock, even when one of the driving wheels is in the air, the vehicle becomes powerless / useless as the wheel with the least resistance, i.e the one in the air keeps spinning and the stuck wheel stuck for good.. The axle Diff locks help in such cases..

What we do without difflocks is to ensure momemtum to cross the hurdle especially if we think that one of the wheels will be airborne. The momemtum and the brute force will transport the jeep across the obstacle..

Hope am clear.

[tsk1979]

but won't a Limited slip Diff take care of this problem. Even if one wheel is spinning free the LSD will ensure that the other tire is spinning(albeit slowly).
So you will always have 4 tires rotating, but the speeds at which they will rotate will be different.

[headers]

Originally Posted by tsk1979

but won't a Limited slip Diff take care of this problem. Even if one wheel is spinning free the LSD will ensure that the other tire is spinning(albeit slowly).
So you will always have 4 tires rotating, but the speeds at which they will rotate will be different.

Yeah the LSD can do this but they are not suited for hardcore off roading..meaning..if 1 wheel is stuck deep and you require full power to the other wheel..LSD may not be able to help..and the full power will not be transmitted in LSD as a difflock.. In simple words a difflock is like a rigid axle..

[StarScream]

engaging story and a great testimonial for the GV

[Alfa_Kilo]

Originally Posted by tsk1979

but won't a Limited slip Diff take care of this problem. Even if one wheel is spinning free the LSD will ensure that the other tire is spinning(albeit slowly).
So you will always have 4 tires rotating, but the speeds at which they will rotate will be different.

Apart from diff locks, only the torque biased Torsen diff can help in this sitiuation. With some left foot braking and internal preload, a Torsen can transfer torque to the slower wheel. Torsens generally work much better than conventional LSDs, but require more frequent oil changes.

[Samurai]

The GV does have the torque sensing LSD. Check this: GLOBAL SUZUKI >>> GLOBAL COMMUNICATION MAGAZINE

During normal 4H, the centre LSD absorbs differences between front and rear wheel speeds and keeps the front/rear torque split at 47:53. This is the normal driving mode.

However, since front and rear diffs are open, any wheel up in air or without traction will take away the torque from the other wheel, won't it? In other words, even when center diff lock is applied in GV, if I don't have traction in one wheel in front and one in rear, I am sitting duck. Is this correct?

Since there is no LSD in front or rear diffs, the center lock mode won't be of too much help in very slippery conditions. Is my understaning correct? Some say only if the diagonally opposite wheels are spinning, it will be stuck. How is that?

[Alfa_Kilo]

@Samurai

With the centre diff locked, one can still get stuck if either wheel at each axle looses grip. The same thing will happen in a traditional transfer case equipped vehicle like the Gypsy.

There is no direct mechanical connection between the front and rear wheels, but there is a solid connection between the front and rear diffs.

Have you decided on the tyres yet?
OT: snow chains also help in soft mud, if used on H/T or A/T tyres. They provide the same traction as M/T tyres.

[Samurai]

Originally Posted by Alfa_Kilo

With the centre diff locked, one can still get stuck if either wheel at each axle looses grip. The same thing will happen in a traditional transfer case equipped vehicle like the Gypsy.

That could be any wheel right, not just diagonally opposite wheels? If both the left wheels loose traction, GV will get stuck.

This is where Gurkha excells I think. Usually it is a 2WD drive. When 4WD is applied in Gurkha, it is equal to 4WD Lock mode in GV. However, Gurkha can further go ahead and selectively lock front, rear or both diffs. In such a case even if 3 wheels loose traction, the remaining one wheel can pull it out. That's what makes Gurkha such a superior off-roader.

Originally Posted by Alfa_Kilo

OT: snow chains also help in soft mud, if used on H/T or A/T tyres. They provide the same traction as M/T tyres.

Damn, that is a very good idea. But that may not work that well in rocky conditions, I suppose. Never the less, it is a good idea to have snow chains in muddy offroading situations. Any idea where I can buy snow chains in India?

[Alfa_Kilo]

Originally Posted by Samurai

That could be any wheel right, not just diagonally opposite wheels? If both the left wheels loose traction, GV will get stuck.

Thats right

Originally Posted by Samurai

This is where Gurkha excells I think. Usually it is a 2WD drive. When 4WD is applied in Gurkha, it is equal to 4WD Lock mode in GV. However, Gurkha can further go ahead and selectively lock front, rear or both diffs. In such a case even if 3 wheels loose traction, the remaining one wheel can pull it out. That's what makes Gurkha such a superior off-roader.

Only if it was not made by Force...

Originally Posted by Samurai

Damn, that is a very good idea. But that may not work that well in rocky conditions, I suppose. Never the less, it is a good idea to have snow chains in muddy offroading situations. Any idea where I can buy snow chains in India?

No idea, but you try to get them fabricated somewhere, shouldn't be too difficult. Snow chains will damage tyres over hard ground, and also reduce traction.

[McLaren Rulez]

Samurai,
Can you tell me how the GV rides on normal potholed roads especially when unloaded? Read reports that its bumpy if not fully loaded and wanted to clarify..

[Samurai]

I normally ride alone and I don't find it harsh at all over pot holes.