Centre Diff Lock

[Drew90]

Hey Everyone,

Had read some conflicting opinions about when to use and when not to use the central diff locks. Currently I only use them when I need to, but have heard people talking about having them on all the time over slippery terrains. What's the proper story?

Cheers

[isuzurover]

Hey Everyone,

Had read some conflicting opinions about when to use and when not to use the central diff locks. Currently I only use them when I need to, but have heard people talking about having them on all the time over slippery terrains. What's the proper story?

Cheers

It is largely a matter of personal opinion/preference.

My view is that engaging the CDL as soon as you leave a hard packed surface will reduce wear and heat buildup in the T-case and centre diff.

Spinning one wheel offroad will rapidly wear the centre diff and/or degrade the t-case oil.

If I am driving along hard packed dirt roads I won't bother - or if I am going on and off bitumen repeatedly then I won't bother.

[Grizzly_Adams]

Hi Drew,

Land Rover's advice is to engage the Central Diff-lock as soon as you are no longer on a fixed/hard surface (eg. bitumen).

The logic behind this is because it improves the vehicle grip and hence safety - however these days the advantage has been negated somewhat by the advent of traction control.

[disco2hse]

It is largely a matter of personal opinion/preference.

My view is that engaging the CDL as soon as you leave a hard packed surface will reduce wear and heat buildup in the T-case and centre diff.

Spinning one wheel offroad will rapidly wear the centre diff and/or degrade the t-case oil.

If I am driving along hard packed dirt roads I won't bother - or if I am going on and off bitumen repeatedly then I won't bother.

wot he said, except that I also turn it of when I am going down a steep incline and I am letting the wheels find their own traction in first gear Lo, and when I am going along a sidling because I find that sometimes the rear wheels can screw themselves down the slope.

[isuzurover]

...except that I also turn it of when I am going down a steep incline and I am letting the wheels find their own traction in first gear Lo, and when I am going along a sidling because I find that sometimes the rear wheels can screw themselves down the slope.

Conversely, I (and many others) engage my rear locker (as well as CDL) when going down steep slopes or traversing sidslopes offroad.

With the CDL engaged, if you get crossaxled while going downhill then the vehicle will race forward. With no CDL, only one wheel has to lift for the same to happen.

With CDL+rear locker, as long as at least 1 rear wheel is on the ground, you will have an even rate of descent and the vehicle will track straighter.

(n.b. This is on a vehicle without HDC/ETC - however the same should still apply).

[disco2hse]

:)

That's if you have a rear locker ;)


Conversely, I (and many others) engage my rear locker (as well as CDL) when going down steep slopes or traversing sidslopes offroad.

With the CDL engaged, if you get crossaxled while going downhill then the vehicle will race forward. With no CDL, only one wheel has to lift for the same to happen.

With CDL+rear locker, as long as at least 1 rear wheel is on the ground, you will have an even rate of descent and the vehicle will track straighter.

(n.b. This is on a vehicle without HDC/ETC - however the same should still apply).

[isuzurover]

:)

That's if you have a rear locker ;)

True, however HDC/ETC should perform a similar function???

I also have tried CDL vs no CDL down steep (cross axley) hills, and CDL engaged is much safer and more controlled IME.

[disco2hse]

That's if you have HDC/ETC :)


True, however HDC/ETC should perform a similar function???

I also have tried CDL vs no CDL down steep (cross axley) hills, and CDL engaged is much safer and more controlled IME.

Well, these things are related to the vehicle and many other factors like how rocky, muddy, slippery, etc. For most places where I need to use first lo CDL and going down an incline it is too risky because I have found the wheels tend to lock up (front and rear) and I prefer to keep them turning. That means if they are all turning at different speeds then no problem, at least they are turning and I am not skating. But I accept that others will have different experiences :)

I guess in answer to the OP, you need to know your vehicle and make your choices accordingly. There is no one rule.

[isuzurover]

That's if you have HDC/ETC :)



Well, these things are related to the vehicle and many other factors like how rocky, muddy, slippery, etc. For most places where I need to use first lo CDL and going down an incline it is too risky because I have found the wheels tend to lock up (front and rear) and I prefer to keep them turning. That means if they are all turning at different speeds then no problem, at least they are turning and I am not skating. But I accept that others will have different experiences :)

I guess in answer to the OP, you need to know your vehicle and make your choices accordingly. There is no one rule.

You are talking about muddy/greasy hills mainly? Certainly a different kettle of fish to rocky/rutted (but dry) hills.

For greasy hills I have always selected 1st low +CDL and then accelerated if the wheels start to lock up.

Don't you find that the vehicle tries to pivot around if one front wheel locks up with CDL disengaged?

[disco2hse]

You are talking about muddy/greasy hills mainly? Certainly a different kettle of fish to rocky/rutted (but dry) hills.

Yes. We don't so many rocky dry slopes here. Too much rain.


For greasy hills I have always selected 1st low +CDL and then accelerated if the wheels start to lock up.

Don't you find that the vehicle tries to pivot around if one front wheel locks up with CDL disengaged?

Certainly if they do lock up one must gun it. But I have found that the bum swings around more if I have CDL engaged. Of course things may not be perfectly straight under there :D

[Naks]

Currently I only use them when I need to, but have heard people talking about having them on all the time over slippery terrains. What's the proper story?

As soon as you leave tar, engage CDL and reduce tyre pressures.

[Beckford]

I always engage the centre diff lock (CDL) when on technical tracks.

Please correct me if this wrong; Worst case:

CDL not engaged: 1 wheel turns
CDL engaged: 1 wheel turns at front, 1 wheel turns at back
Rear Diff Locker engaged: Both wheels turn at back (if you have one)
Front Diff Locker engaged: Both wheels turn at front (if you have one)

[portafilter]

As soon as you leave tar, engage CDL and reduce tyre pressures.

X2 I just had my trans case rebuilt as a consequence of previous owner not locking ctr diff enough on gravel, or basically anything that wasnt sealed. Flogged out ctr diff bearing and thrust washers as its not designed to be loaded with uneven drive while off road. Was told its better to use it too much than not enough. Rebuild also made huge improvement to drivetrain backlash and hard gear changes.

[isuzurover]

I always engage the centre diff lock (CDL) when on technical tracks.

Please correct me if this wrong; Worst case:

CDL not engaged: 1 wheel turns
CDL engaged: 1 wheel turns at front, 1 wheel turns at back
Rear Diff Locker engaged: Both wheels turn at back (if you have one)
Front Diff Locker engaged: Both wheels turn at front (if you have one)

Yes,
Yes,
If you have CDL disengaged, but a front OR rear locker engaged, then one of the wheels on the unlocked axle will turn and you will be no better of than having no locker.

one Locker + CDL engaged, then you will aways have at least 3 wheels turning.

F+R locker but CDL disengaged, then only 2 wheels on one of the axles turning (again worst case - e.g. when climbing a steep hill, drive will go to the front as it will have less load).

[stig0000]

iv tryed with and without on dirt rds,, if i feel it sliding about and that,, i just slow down:angel:

i only put cdl in if i recon theres gona be a chance of wheel lift, and if it looks hectic enof then the locker gose on,

[camel_landy]

Conversely, I (and many others) engage my rear locker (as well as CDL) when going down steep slopes or traversing sidslopes offroad.

With the CDL engaged, if you get crossaxled while going downhill then the vehicle will race forward. With no CDL, only one wheel has to lift for the same to happen.

With CDL+rear locker, as long as at least 1 rear wheel is on the ground, you will have an even rate of descent and the vehicle will track straighter.

(n.b. This is on a vehicle without HDC/ETC - however the same should still apply).

The Defender doesn't have HDC anyway... ;)

Without the locker, lifting a wheel will cause the wheel to rotate backwards, the vehicle will surge forwards and when the wheel comes back in contact with the ground it has the potential to damage the axle.

In this type of scenario, you are taught to feather the brake slightly as that will help prevent the wheel from rotating backwards.

...and FWIW - I'll engage CDL when I'm on any loose surface. The important bit is to make sure you disengage before you hit the black stuff!!

M

[rick130]

Oh well, I'm the odd one out (again) as I only use the CDL when i need it. ie. real 4WDing where one may lift a wheel or spin a tyre.

portafilter, I drive loose gravel all the time and never bother with the CDL and the car has 280,000km ATM.
The t/case is still holding up and drives ok (which I'm surprised at as it had different tyre sizes front/rear when I bought it with 76,000km on the clock. The t/case fluid was black from being overheated)

I can imagine burning up the centre diff if the CDL isn't used in really loose/muddy conditions or lifting wheels and the driver just keeps the right foot into the firewall but on a normal gravel/dirt/shale road ?

[vnx205]

That makes two of us Rick.

I had been led to believe that what destroyed the centre diff was either the front prop shaft and rear prop shaft turning at significantly different speeds for a considerable time (eg one wheel allowed to spin a lot) or the two prop shafts turning at slightly different speeds and suddenly being made to turn at the same speed (eg a spinning wheel suddenly getting grip).

Neither of those things happens if you drive sensibly on dirt roads.

[isuzurover]

Rick and vnx205

I suppose the consensus is that - it can't do any harm to lock the CDL whenever you drive on loose surfaces...

[camel_landy]

Rick and vnx205

I suppose the consensus is that - it can't do any harm to lock the CDL whenever you drive on loose surfaces...

Exactly... The harm comes if you use CDL on high grip surfaces.

M

[rick130]

Rick and vnx205

I suppose the consensus is that - it can't do any harm to lock the CDL whenever you drive on loose surfaces...

I agree, but usually the advocates of engaging the CDL espouse gloom, doom and disaster if you don't engage it, at least going off previous threads.

[rovercare]

I agree, but usually the advocates of engaging the CDL espouse gloom, doom and disaster if you don't engage it, at least going off previous threads.

I think it's more of a reference in regards to heading bush, I lock on most anything that isn't high speed dirt, or if pushing I'll lock it then too, far better balance and braking, but left open on general bland dirt roads

[Beckford]

The t/case is still holding up and drives ok (which I'm surprised at as it had different tyre sizes front/rear when I bought it with 76,000km on the clock. The t/case fluid was black from being overheated)

When you engage the CDL I thought the 4 tyres should be the same pressure and the SAME SIZE!

How much off road work with the CDL engaged did it do before you bought it?

[bee utey]

When you engage the CDL I thought the 4 tyres should be the same pressure and the SAME SIZE!

That myth again. Tyre pressure within limits doesn't change the effective distance travelled per revolution of tyre. The invariant length is the tyre's steel belt.

As for engaging the CDL, I would only do it on a surface where significant slip is possible, like ball-bearing gravel or sand. The act of turning the steering makes the front axle travel a different distance to the rear axle, a much bigger effect than any minor variation in rolling diameter.

[vnx205]

Rick and vnx205

I suppose the consensus is that - it can't do any harm to lock the CDL whenever you drive on loose surfaces...


Exactly... The harm comes if you use CDL on high grip surfaces.

M


I agree, but usually the advocates of engaging the CDL espouse gloom, doom and disaster if you don't engage it, at least going off previous threads.


I think it's more of a reference in regards to heading bush, I lock on most anything that isn't high speed dirt, or if pushing I'll lock it then too, far better balance and braking, but left open on general bland dirt roads

Yes, I guess there are places where it is definitely necessary to engage, places where it is definitely wrong to engage and a lot of territory in between where it is an option and no harm will be done either way.

I think I was getting the same impression as Rick130. There seemed to be a body of opinion developing that you were courting disaster unless you engaged the moment you left the bitumen.

I think the fact is that those who engage on dirt roads will probably enjoy the same centre diff reliability as those who don't.

[Drew90]

haha thanks guys clear as mud. Just Kidding

[Loubrey]

The old Land Rover chant comes to mind (and yes, first used in Land Rover training for the Camel Trophy) - "As slow as possible, as fast as necessary”.

I’ve personally based CDL selection on the speed you are planning to do. Under 50km/h I always lock the diff. The reason you are going that slow would most probably be terrain dependant and when you decide definitely need it, it would usually be too late.

Above 50kmh on gravel roads I allow the differential to decide where the power needs to be.

These were military guidelines (SADF) for driving Defenders in the late 80’s and I’ve sort of stuck to the concept.

[camel_landy]

The old Land Rover chant comes to mind (and yes, first used in Land Rover training for the Camel Trophy) - "As slow as possible, as fast as necessary”.
Shouldn't that be "As fast as possible, as slow as necessary..." :p


Above 50kmh on gravel roads I allow the differential to decide where the power needs to be.


...it don't work like that. In fact, it's the complete opposite.

A differential is a mechanical device and it will ONLY transmit the power to the path of least resistance... i.e. the wheel with NO traction. If you don't believe me, just jack up one of your wheels and see what happens when you start to drive. ;)

M

[Loubrey]

A differential is a mechanical device and it will ONLY transmit the power to the path of least resistance... i.e. the wheel with NO traction. If you don't believe me, just jack up one of your wheels and see what happens when you start to drive. ;)

M

I don't disagree at all regarding the workings of the centre diff. The fact remains that on roads as encountered in rural West Australia and to a large extent the gravel roads of South Africa (where I learned to drive) you travel great distances where you need to travel between 70km/h and 80km/h or you'll never get there. To a large extent 2WD is sufficient if you have enough driver ability to keep it on the road. Very seldom, if ever do you encounter "high speed" single wheel traction loss and the best thing remain allowing the Defender's natural configuration permanent 4WD to operate as designed.

I currently drive a Puma 90 and we have roads here known as "rail access roads" with a speed limit of 80km/h which everybody including the road trains travel at. I never engage the diff lock for these journeys and I never hear a peep out of the TC, which to me indicates I do not at any point suffer traction loss on any individual wheel.

There is many schools of thought on the matter including the Mine's requirement for Hilux's to permanently remain in high range 4WD which I personally don't agree with either. As I said in my previous e-mail that's the way I've been taught and after close on a million km's travelling in Land Rovers building roads all over the world I'm still to loose a Land Rover transfer case or gearbox.

[portafilter]

Oh well, I'm the odd one out (again) as I only use the CDL when i need it. ie. real 4WDing where one may lift a wheel or spin a tyre.

portafilter, I drive loose gravel all the time and never bother with the CDL and the car has 280,000km ATM.
The t/case is still holding up and drives ok (which I'm surprised at as it had different tyre sizes front/rear when I bought it with 76,000km on the clock. The t/case fluid was black from being overheated)

I can imagine burning up the centre diff if the CDL isn't used in really loose/muddy conditions or lifting wheels and the driver just keeps the right foot into the firewall but on a normal gravel/dirt/shale road ?

Yeah. I'm not sure what happened with last owner. Maybe they just drove it like they stole it? May also have been tough on the trans case if the TC is kicking in all the time.

[camel_landy]

I currently drive a Puma 90 and we have roads here known as "rail access roads" with a speed limit of 80km/h which everybody including the road trains travel at. I never engage the diff lock for these journeys and I never hear a peep out of the TC, which to me indicates I do not at any point suffer traction loss on any individual wheel.

You generally won't get a 'peep' out of TC in those scenarios. (Otherwise known as "Talent Control" - When you run out of driving talent, the car takes control... ;))

Wheelspin is caused by excessive torque. If you're cruising at 80km/h, you're generally not giving it bootfulls of torque.

On top of that, together with the "As slow as possible, as fast as necessary" you are also taught the there is a balance between "Traction vs Momentum". At 80km/h you have plenty of momentum, so therefore you don't need much traction...

However, if you dropped it a cog or two and gunned the throttle on a bend... ;)

Yes, you can argue that you don't need to engage diff-lock until you need it but it's one of those things where it's easier to have it engaged for those times when you don't expect that you need it. It doesn't do any harm and it could make your life easier!

It's like HDC on the other cars, although you don't need it climbing a hill, it's good to have it pre-engaged as it is one less thing to have to fiddle with, if you fail the climb and are now coming down the hill backwards!!

...or turning off DSC...

etc...

M

[camel_landy]

As I said in my previous e-mail that's the way I've been taught and after close on a million km's travelling in Land Rovers building roads all over the world I'm still to loose a Land Rover transfer case or gearbox.

You & me both darlin'...

In this thread, I've not been talking about mechanical sympathy, just purely about technique.

M

[isuzurover]

I currently drive a Puma 90 and we have roads here known as "rail access roads" with a speed limit of 80km/h which everybody including the road trains travel at. I never engage the diff lock for these journeys and I never hear a peep out of the TC, which to me indicates I do not at any point suffer traction loss on any individual wheel.



Conversely, down in the south west while driving on "pea gravel" at high speeds, the 110 handles much nicer and feels much safer with the CDL engaged.

[Loubrey]

Conversely, down in the south west while driving on "pea gravel" at high speeds, the 110 handles much nicer and feels much safer with the CDL engaged.

Agree 100% with you about the pea gravel. Even with the CDL engaged the stuff is likely to give you the odd bout of sweats! I've only travelled that area on holidays and never in a rush. I take my hat off to you guys travelling any sort of speed on it...

[isuzurover]

Agree 100% with you about the pea gravel. Even with the CDL engaged the stuff is likely to give you the odd bout of sweats! I've only travelled that area on holidays and never in a rush. I take my hat off to you guys travelling any sort of speed on it...

My first experience of driving on it was just after moving to WA - driving a hired hyundai accent (not allowed to go offroad) - out to watch the WRC on freshly graded roads (heaps of loose pea gravel). A slight blip of the accelerator and the front end would slide all over the place.

I take my hats off to the WRC drivers!!!

[defrover]

You generally won't get a 'peep' out of TC in those scenarios. (Otherwise known as "Talent Control" - When you run out of driving talent, the car takes control... )

Wheelspin is caused by excessive torque. If you're cruising at 80km/h, you're generally not giving it bootfulls of torque.

On top of that, together with the "As slow as possible, as fast as necessary" you are also taught the there is a balance between "Traction vs Momentum". At 80km/h you have plenty of momentum, so therefore you don't need much traction...

However, if you dropped it a cog or two and gunned the throttle on a bend...

Yes, you can argue that you don't need to engage diff-lock until you need it but it's one of those things where it's easier to have it engaged for those times when you don't expect that you need it. It doesn't do any harm and it could make your life easier!



Sorry For the late reply but in my Quick Start Guide it clearly states "Do not use CDL if travelling above 60km/h.

I would probably leave cdl open until you cant maintain forward movement effortlessly.

[Loubrey]

Safe off-road driving technique is to ALWAYS have centre diff locked in high range and stick to 90km/h or as close to as you safely can.

Quick start is just that... how not to damage your car and cause warranty issues when you start out driving Defenders. To wait until you can't maintain forward movement would be way to late on rough terrain or on you roof having slid off on a pea gravel bend.

My first 90 did around 320,000km before it was sold on and at least a third of that would have been at cruising speed in high range with the diff locked.

I don't like changing the transfer box on the move, but some guys on here has got the technique down pat. Again, stopping and selecting CDL only once you've lost momentum and traction is definitely not the way its done...

IMO not having Land Rover Experience in Australia is a serious drawback to the safe and effective operation of Defenders.

Cheers,

Lou

[2stroke]

I'm surprised how many people drive around with their centre diff locked. I'd be worried I'd hit a piece of high traction surface and wind it up (more likely with me, forget to unlock it when I get on bitumin). I treat it like the rear Maxidrive, only lock it before I need it, then unlock again after we're through the soft or broken patch. Both lock and unlock on the move, just lift off throttle, flick lever, the spring pushes the locking dog clutch into engagement when the teeth lign up and unlocks when the load is off the teeth. I don't drive around on dirt roads with the maxidrive locked for fear I might spin a wheel.:D

[ozscott]

Traction control does not assist in high speed dirt...anti slew would but deefers and d2 etc dont have that. Locking the CD on high speed dirt makes handling more positive...feels much better.

Cheers

[ozscott]

Both my d1 a d d2 manuals dont say anything about not traveling with cd engaged above a certain spees...in fact they say you can lock on the move at any speed. I have shifted to lock many times at 90 plus.

Cheers

[isuzurover]

I'm surprised how many people drive around with their centre diff locked. I'd be worried I'd hit a piece of high traction surface and wind it up (more likely with me, forget to unlock it when I get on bitumin). I treat it like the rear Maxidrive, only lock it before I need it, then unlock again after we're through the soft or broken patch. Both lock and unlock on the move, just lift off throttle, flick lever, the spring pushes the locking dog clutch into engagement when the teeth lign up and unlocks when the load is off the teeth. I don't drive around on dirt roads with the maxidrive locked for fear I might spin a wheel.:D

Sorry but this shows a lack of understanding.

A cross axle diff lock is different to a front-rear diff lock.

With the CDL unlocked you can spin one front OR rear wheel and lose all drive. With the CDL locked you need to spin one front AND one rear wheel.

With the CDL locked the cross axle differentials still work fine...

If you are driving in a (mainly) straight line there will be no CDL windup.

The new Ashcroft centre (lockable) LSD is of course the best option. The fact that those who have fitted the LSD have reported greatly improved dirt road driving with the LSD (over an open diff) is evidence that those with an open diff should lock it when driving on high speed dirt/gravel roads.

[2stroke]

Sorry but this shows a lack of understanding.

A cross axle diff lock is different to a front-rear diff lock.

With the CDL unlocked you can spin one front OR rear wheel and lose all drive. With the CDL locked you need to spin one front AND one rear wheel.

With the CDL locked the cross axle differentials still work fine...

If you are driving in a (mainly) straight line there will be no CDL windup.

The new Ashcroft centre (lockable) LSD is of course the best option. The fact that those who have fitted the LSD have reported greatly improved dirt road driving with the LSD (over an open diff) is evidence that those with an open diff should lock it when driving on high speed dirt/gravel roads.
Oh I understand exactly how diffs and difflocks work. I also understand that if turning corners is part of your driving, the inside and outside AS WELL as the front and rear need to travel a different distance. Instead of this difference being accounted for in the differentials (that's what they're designed for after all) it must be taken care of by tyre slip in a locked situation, that's the point I was trying to make. I don't think wheels slip enough on a gravel road to wear out centre diff thrust washers, more likely they'll become hammered by windup pressure.

[Dougal]

As soon as you leave tar, engage CDL and reduce tyre pressures.

That's a bit extreme. My driveway isn't tar.

I much prefer the wording in the plate in my rangie. "Engage Diff Lock when traction is likely to be lost"
Or something like that.

Drifting gravel roads counts as losing traction.

[Loubrey]

The point being that all Land Rover operated and endorsed driving instruction teaches that "high speed" (generally less than 90km/h) driving on gravel roads are safer with the CDL engaged.

The CDL makes a significant difference to the longitudinal stability of the car and assists in negating over steer. There is little or no chance to encounter wind up on any short piece of hard surface, especially if you're not turning the vehicle. It's also good habit to have your own mini check list for entering and exiting any loose surface, which in turn will prompt you not to forget your CDL engaged.

As Dougal said, any surface likely to cause loss of traction very much includes "high speed" dirt road driving. Realising that you've lost traction at 90km/h (touch of the brakes, tightening turn, patch of pea gravel etc) doesn't give you much opportunity to then assess the situation and decide to engage your diff lock...

Cheers,

Lou

[Lagerfan]

Being new to 4x4 I'm just ploughing through Robert Pepper's 4WD Handbook (http://www.4wdhandbook.com/) in which he says having the centre locked is fine on pretty much anything other than bitumen (http://www.4wdhandbook.com/rmp/blog/should-you-lock-centre-diff-offroad) (or similar high traction surfaces). Certainly my (limited) experience is the 90 handles much better in the dirt with it on.

Maybe the debate is really about semantics, when is a dirt road not dirt? I tried looking it up but my head spun with all the different types: dirt, gravel, macadam, murram & laterite, aggregate, combo's of all ...

[Dougal]

There are situations though where there is very little traction and you are best without the diff lock in as the extra scrubbing will cause you to break traction.

Ice is one of the few and even then, whether to lock or not depends more on what's at the edge of the ice than the ice itself.

[OffTrack]

Tom Sheppards "The Land Rover Experience" book which accompanied the training courses of the same name in the early 90's says:


When to use diff lock. A simple rule-of-thumb is to use diff lock when you use the low range transfer gears on any loose or slippery surface. Use of low range generally means that you are on difficult or uneven ground and wanting a high tractive effort. Such ground usually has uneven traction characteristics as well as an uneven surface and you will need all the traction (grip) you can get. Locking the centre differential will precluded loss of traction resulting from potential front/rear differences in grip.

High range diff lock? It is possible to engage diff lock in high range too. When, if ever, is this desirable? It will be useful to engage diff lock in high range when driving on potentially difficult surfaces such as wet grass, mud, loose or packed snow, or lose sand on tracks or in open desert.

When to de-select diff lock? It is important to de-select diff lock when on any hard grippy surfaces such as tarmac or concrete (wet or dry) whether you are in high or low range.


Which is roughly what Robert Pepper is advising. You can safely lock on anything that isn't a hard grippy surface.

I seem to recall being taught to engage Low Range and Lock CDL when doing the LROCV 4wd basics course. I usually will lock the CDL in high if the track/road has a loose surface or slippery surface.

cheers
Paul

[FeatherWeightDriver]

Ice is one of the few and even then, whether to lock or not depends more on what's at the edge of the ice than the ice itself.

At the risk of going off topic - ice is the edge case to just about all driving techniques and driving aids.

I have had the unfortunate pleasure (admittedly a many years ago now, with likely less advanced ABS tech) of finding out how ABS and ice play together - hint: it does not end well for the car.

In my instance the ABS gave a few kicks, decided there was no traction and let the car free wheel in to the nearest solid object in front of me. Once I realised what was going on the handbrake only slowed me a bit, but certainly did a better job than freewheeling. Then again by that stage steering was only useful as something to keep me (the driver) busy on the way to the inevitable.

Has anyone tested a Puma ABS on ice? :eek:

[Loubrey]

Back in 2004 I did a double pirouette in a brand new Discovery 2 on a country lane in Worcestershire. :eek: Luckily it was before the farmer's annual hedge trim and there was a lot of foliage and a silted up shallow ditch to break the momentum...

Safe to say slightly primitive TC and ABS is just about useless on black ice.

Disco 3 and 4 is a completely different kettle of fish though...

Cheers,

Lou

[Dougal]

At the risk of going off topic - ice is the edge case to just about all driving techniques and driving aids.

I have had the unfortunate pleasure (admittedly a many years ago now, with likely less advanced ABS tech) of finding out how ABS and ice play together - hint: it does not end well for the car.

In my instance the ABS gave a few kicks, decided there was no traction and let the car free wheel in to the nearest solid object in front of me. Once I realised what was going on the handbrake only slowed me a bit, but certainly did a better job than freewheeling. Then again by that stage steering was only useful as something to keep me (the driver) busy on the way to the inevitable.

Has anyone tested a Puma ABS on ice? :eek:

I can attest that the ABS in a 2000 year 100 series cruiser is absolutely useless on ice.
Driving down a skifield road, one pair of wheels on frozen gravel, one pair on ice. ABS keeps releasing the brakes on all four, leaving you driving a 2.8t toboggan.

I tested the abs brakes on a 98 nissan road car on the same hill in the same situation. No problem, it just pulsed the wheel that needed it.