ABS on corrugations

Submitted: Wednesday, Oct 29, 2014 at 08:04
ThreadID: 109972 Views:4066 Replies:11 FollowUps:40
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Rosco from way back began a great thread about tyre pressures on corrugations.It raised a number of questions about speed , suspensions loads etc but the issue of braking never surfaced so rather than hijack his thread I thought I would begin another.
My 80 series cruiser is as faithful as a mongrel dog but it has ABS which on the black top is fine but on dirt & especially corrugated dirt is a nightmare to the extent that now I have a system of negating it's operation. This allows me to brake much more effectively than with different wheels grabbing & letting go & causing an imbalance of the vehicle & van.
I run my tyre pressures somewhat lower on dirt than highway & drop my speed accordingly . The lower tyre pressures also help markedly in reducing the braking distance required but if the ABS is connected it still causes a headache.
Does anybody have similar issues ?
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Batsy
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Reply By: DmaxQld - Wednesday, Oct 29, 2014 at 08:41

Wednesday, Oct 29, 2014 at 08:41
So what you are saying is that you switch your ABS off when on the dirt? Or did I read that wrong?
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Follow Up By: Member - batsy - Wednesday, Oct 29, 2014 at 08:49

Wednesday, Oct 29, 2014 at 08:49
Correct, the system is rendered inoperative
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Follow Up By: DmaxQld - Wednesday, Oct 29, 2014 at 08:58

Wednesday, Oct 29, 2014 at 08:58
Wow, I was hoping you wouldn't say that. Has incredibly stupid of you.

I have done extensive testing of ABS systems as a professional driver. In fact, our team managed to break the original Holden Commodore ABS system and Holden re-engineered as a result.

Where ABS is truly shines is on broken or wet surfaces and gravel. In a non ABS vehicle I can brake in a shorter distance than an ABS equipped vehicle BUT only on a good, dry surface. In all other scenarios, an ABS equiped vehicle is far superior and will brake to a stop in a shorter distance.

By disabling your ABS you are a danger to yourself, your passengers and other road users. I only wish I had some way of reporting your behaviour to the authorities but being anonymous on here prevents that.
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Follow Up By: Member - Serendipity(WA) - Wednesday, Oct 29, 2014 at 09:56

Wednesday, Oct 29, 2014 at 09:56
I don't get it. My car does not have ABS - does that make me 'a danger to myself, my passengers and other road users'. How can it be applied to one car and not to another.

Some car manufacturers bring out a switch to disable the ABS like when the 4x4 is activated for 'off road' conditions. So again - how does that make it more dangerous when manufacturers are implicitly acknowledging the problems with ABS for off road conditions.




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Follow Up By: Sigmund - Wednesday, Oct 29, 2014 at 09:59

Wednesday, Oct 29, 2014 at 09:59
Older ABS system were a pox on gravel, at least where braking is aided by building up and pushing a mound ahead of the wheels.

Newer systems are sposed to be better but an acquaintance who's a suspension expert disables the ABS on his Impreza when he goes onto dirt.
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Follow Up By: Kris and Kev - Wednesday, Oct 29, 2014 at 10:07

Wednesday, Oct 29, 2014 at 10:07
I have never had a problem with my braking on corrugations, either towing or not. The ABS works like it should. On the hard stuff during driver training I was able to stop better with the ABS turned off, on a straight drive that is, but put one side on some dirt and it was a different thing again. Same when turning, if you need to brake suddenly the ABS does its job. If his ABS are causing such problems I would get the vehicle checked out. Kevin
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Follow Up By: Member - batsy - Wednesday, Oct 29, 2014 at 10:33

Wednesday, Oct 29, 2014 at 10:33
The ABS has been checked as has the entire brake system & has been found to be working in accordance with the original settings.
I have driven current vehicles with ABS on the dirt & they are markedly better than my 1997 vehicle.
I have also driven not so long ago an ABS equipped vehicle on dirt in competition with the ABS disconnected . To the best of my knowledge none of my competitors with ABS in their vehicles had it operative.
Myself & four friends who average nearly fifty years of driving experience ( four of us have had quite considerable competition experience on dirt) with similar aged/type vehicles have all tested & come to the same conclusion that with our vehicles on loose gravel/corrugations ABS is best left inoperative .Hard dirt/highway is fine with ABS.
By the way my vehicle has a switch to turn the ABS system off. I believe it is original.
Cheers
Batsy
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Follow Up By: MEMBER - Darian, SA - Wednesday, Oct 29, 2014 at 10:33

Wednesday, Oct 29, 2014 at 10:33
Ah Dmax...such a silly and thoughtless way of responding to Batsy's topic.....don't 'professional drivers' need to demonstrate common courtesy toward others ? As for Batsy being anonymous...who are you ?
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Follow Up By: pop2jocem - Wednesday, Oct 29, 2014 at 11:23

Wednesday, Oct 29, 2014 at 11:23
Mr Dmax, a question if I may.
Considering that your good self is a professional driver and expert on all things ABS, and going by your statement that you are capable of bringing a non ABS equipped, or if so equipped, disabled, ABS system vehicle to a more controlled stop on a good dry surface than with the ABS enabled, is it your hypothesis that ABS could result in a collision whereas a non ABS could have avoided said collision?
Considering that the far greater part of driving in countries such as Australia is done on bitumen, which in most cases could be classified as a good surface, should we, the non professional drivers have the ABS disabling function connected to the windscreen wiper operating system so that when the road is nice and dry the ABS does not operate.
Further, should a vehicle also have a driver sellectable switch for use on the surface types as well as the windscreen wiper ABS disabling feature?
Batsy, the OP, by his experience states that he is capable of bringing his vehicle to a more controlled stop with ABS disabled than with it in operation, but without having driven his vehicle in any conditions, let alone on the gravel surfaces he is talking about, you want, not only to come onto a public forum and call him stupid, (your word) but indicate that it is your wish to report him to some authority.
Going by the impression your reply has created in my mind is that you just may have to learn the fine art of getting your point across without stabbing someone with it.
It is called tact.

Cheers
Pop
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Follow Up By: The Bantam - Wednesday, Oct 29, 2014 at 11:59

Wednesday, Oct 29, 2014 at 11:59
I think a lot of this comes down to the adequacy of the braking systems and the performance of the ABS.

Some vehicle manufacturers have had difficulty in manufacturing braking systems that behave well.....some of the american derived vehicles have had shocking braking systems....braking systems that simply do not stop straight or without wheels locking up prematurely

These designers of poor braking systems love ABS, because it can make poorly designed brakng systems behave tolerably well in normal driving.......but these vehicles are very much dependent on the ABS to stop at all well.

Then there are some of the early ABS braking systems....often on the vehicles mentioned above......that have fundamentally poorly designed braking systems...some of these ABS systems where very intrusive and behaved poorly indeed on rough surfaces.

In fact there where early ABS equiped vehicles that stopped poorer than competing vehicles that had no ABS....especially on rough surfaces.

Turn the ABS off on a vehicle with a fundamentally poorly ballanced braking system and you could have a real hand full.

Leave it on and it may not stop well at all on rough surfaces.

A vehicle with a fundamentally well designed braking system will rarely be activating the ABS and wont be depending on it to stop in a civilised manner in most situations.

ALSO a modern well designed ABS system will not make its presence felt except in the most extreem of situstions..and may perform a hepp of a lot better on rough surfaces than many of the earlier examples.


So it is not possible to generaise about ABS systems and rough roads.


The other thing that many dont consider...is that braking is significantly effected by the performance of the suspension ( especialy shockabsorbers) and how the vehicle is loaded or the weight is distributed.

ABS like Vehicle stability controll may be badly effected by poor shockabsorbers, suspension and tyre modifications.

and yes many ..or most 4wds disable ABS and VSC in low range.

cheers
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Follow Up By: Member - Tony H (touring oz) - Wednesday, Oct 29, 2014 at 12:24

Wednesday, Oct 29, 2014 at 12:24
I've owned three 80 series all had ABS, all especially the first (early model 80 series) had appalling ABS operation, really really scary at times.
I didn't disable the function.....but gee I really slowed up when I travelled on loose dirt or corrugations.
Currently on my third 200 series, the ABS operation is a LOT better, but you still have to be cautious on loose dirt (as you should)
Insanity doesnt run in my family.... it gallops!

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Follow Up By: gbc - Wednesday, Oct 29, 2014 at 15:24

Wednesday, Oct 29, 2014 at 15:24
Wow dmaxqld, way to make an entrance. I'll also stick my hand up as one who has been incredibly stupid. The 80 and 100 series on loose surfaces (grossly exaggerated when towing) has a mostly inept braking system, and it was considered de rigeur to pull the abs fuse when offroad.
I used to travel for work and also well remember how efficient the first series of commodore abs was on gravel. Opening the door and putting your foot down would have assisted more.
I absolutely adore abs, ebd, eba and anything else, but if you were a professional driver back when this stuff had teething problems -and missed it !- then it is for those whom share the road with you that I weep.
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Reply By: Ron N - Wednesday, Oct 29, 2014 at 12:18

Wednesday, Oct 29, 2014 at 12:18
I don't recall a sillier and more "officious" reply to any post than Dmax's reply to Batsy.
Us older blokes have survived for 50 yrs or more, driving ancient chariots (from factory new) that no doubt rate as "total death traps" in Dmax's superior opinion.

We had to cope with Holden drum brakes that were always known as "go-faster" brakes.
Younger people would probably be appalled and unable to cope with ancient drum brakes that pulled you off line, more often than pulled you up, when braking hard.
We had to cope with crossply tyres that constantly "tramlined" without warning on gravel roads, enough to make a racing car driver blanch.

We learnt to cope, and we learnt to handle vehicles that got out of line when braking, or got out of line, when we suddenly hit severe corrugations on one side at speed.
I've had my '77 F100 go sideways in half a second when I suddenly hit deep corrugations on one side at 110kmh.

I possessed the handling skills to swiftly bring it back into line and keep it upright without putting it on its roof - learnt over many years of driving on less-than-satisfactory roads and owning many sub-standard performance vehicles.

Those skills are sadly lacking in the younger generations, because of the constant inroads of exceptionally high technology that are reducing basic driving skills to barely being able to find the ignition key hole.

Much of the new technology is an advance on older technology - but to become totally reliant on extremely complex systems to perform perfectly in every single situation ever ecountered, is foolhardiness.

Adding reduced driving skills to the mix only makes the situation worse. AFAIC, all drivers should be trained on old drum-braked Holdens with dodgy shock absorbers and crossply tyres before they're given their licences.

Cheers, Ron.
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Follow Up By: Bludge - Wednesday, Oct 29, 2014 at 12:48

Wednesday, Oct 29, 2014 at 12:48
Ron,

Stoping distances rated with a calendar... Single lead shoes on a mini was one of my favourites, in dusty conditions when reversing the brakes would lock up solid, remove wheels and hit drums with a mash hammer to release..... :)

I still do most of my braking in advance of a stop and watch people fly past me, braking at the last moment..
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Follow Up By: Member - batsy - Wednesday, Oct 29, 2014 at 13:38

Wednesday, Oct 29, 2014 at 13:38
Ron I agree with your "tongue in cheek" comments but in reality it's what we had & we were bloody glad to have it.... better than dad's Ford Desoto.
By the way I understand that many of the newer cars now don't even have an ignition key hole....great thing actually as it's real hard to get your key in the ignition switch when you are "legless". HoHo
Cheers
Batsy
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Follow Up By: olcoolone - Wednesday, Oct 29, 2014 at 18:14

Wednesday, Oct 29, 2014 at 18:14
Yes we are all expert drivers and or reflexes are much faster then any dump computer...... just because a computer can calculate 1000's of times a second compared to seconds for the average humane brain shouldn't be considered in the equation.

Ron love to put you to the test and see just how quick you can react and outsmart a computer.

About 5 years ago A Current Affair did it with a bunch of young and old drivers who big noted their abilities ...... after the testing all came away thinking different.

Yes expert drivers we all are.... aren't we!
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Follow Up By: Ron N - Wednesday, Oct 29, 2014 at 19:15

Wednesday, Oct 29, 2014 at 19:15
olcoolone, I've been driving for 49 yrs this year, and I've owned a very wide range of vehicles from motorbikes through to a very wide range of cars, utes, 4WD's, and trucks right through to Macks and 100 tonne Drake low loaders.
I reckon I've done well over 3 million kms in that time and experienced every road surface and traffic condition known.

Sorry if I sound like I'm bragging, but I've managed to last this long without having a major accident of any kind, nor have I ever ROLLED a vehicle, or badly damaged a vehicle - of any kind. Nor have I ever injured or killed anyone in a motor vehicle.

Yes, I've had a few bingles - probably the worst was running through a T-junction in the wheatbelt in the early hours of the morning coming home, when I was 18, and when I was tired and distracted.

However, I've had good trainers who taught me how to develop a good FEEL for what my wheels are doing - to ensure that they're always pointed in the right direction and that judicious amounts of power are applied at just the right time.
I was also taught never to panic brake and only apply enough braking to produce a fast stop without wheel lockup. You develop a FEEL through the vehicle, with improved driving skills, as to what the brakes and wheels are doing.

I spent many formative driving years practising my rally-driving style, broadsiding the old Holden utes around gravel bends at speed, to ascertain just where the limits of the ute and myself were.
I was lucky in that respect, few youngsters today get that experience and training.

I don't believe in allowing computers and sensors to take my driving skills away from me - no matter how good the engineers tell me their computers, algorithms and sensors are. Nothing can replace the human brain and muscles when it comes to assessing a situation that requires a quick response that involves mutiple decisions.

I've avoided a woman who did a U-turn directly in front of me with no indication, and without looking.
I nearly hit the kerb on the far side of the road, such was my drastic response - but neither vehicle touched, and neither did I hit anything else.

I want to see the computer that could make the correct decision for collision avoidance, and respond in the way that I did.
I could have just braked, in which case I would have cleaned her up. I chose to swerve, and then correct, and keep up my speed - which goes against many computer programs.

I've had many other nasty squeaks over the years - such as coming face to face on the crest of a hill at 115kmh, with a Landcruiser traytop towing a huge tandem trailer, which was overtaking a bus over double white lines on the far crest of that hill. What would your computerisation have done?

I had milliseconds to decide what to do, to avoid a 220 kmh head-on. I took the right decision, brake hard in a straight line without locking up, and watch the other drivers eyes to see what he was going to do.
He went to my left into the bush, and I squeezed between him and the bus.

No doubt your computerisation would insist that all vehicles must pass on the correct side, and the computerisation would have my vehicle swerving left to initiate a definite head-on at 200kmh.

Nope, I'm sorry, in some relatively rare situations, computerised aids to driving such as ABS can offer a slight advantage - such as reducing wheel lock up on wet, smooth bitumen - but overall, computerisation of vehicle control is all about dumbing down driving skills, and making up for an abysmal lack of vehicle control skills.
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Follow Up By: olcoolone - Wednesday, Oct 29, 2014 at 21:28

Wednesday, Oct 29, 2014 at 21:28
There is no way you can say skills or electronic aids are better or worse as every near miss or accident is differant and has so many variables.

The only way you can make a true comparison is in a controlled enviroment.

Not once have I said to my self that near miss would of been better is I did not have X electronic aid in my vehicle.

And computers don't panic and don't make mistakes.....humans do.

I don't think people have lost their ability to drive due to electronic aids...... I think people have lost their ability to drive full stop and you get good and bad in old and young people and vehicles and with and without electrical driving aids.

I am not doubting your abilities but I think you milliseconds statement is a little wrong..... Transistors switch in milliseconds......... 1 millisecond is 1 million of a second. You remind me of the fisherman who caught a fish this size ( ) lol
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Reply By: Bludge - Wednesday, Oct 29, 2014 at 12:39

Wednesday, Oct 29, 2014 at 12:39
My view on this is relatively simple.

Dirt roads and corrugations, as many signs are now saying, "Adjust you driving to the conditions" For me that is, drop tyre pressure and drop speed, put it into 4WD if part time vehicle and centre diff lock if constant 4WD (in my case).

When in 4WD the ABS is turned off, front an rear axels are connected and braking is equalised between all 4 wheels.
Then on dirt or corrugated roads steering and braking are improved, with no ABS with the benefits of front wheel and rear wheel drive.

This also reduces strain on the rear drive wheels on part time, and enhances the constant 4WD ability. And no it won't wear the front out, all new part time 4WD except The 79/75 and the Patrol have no free wheeling hubs.

Those concerned with added fuel consumption, well you own a 4WD, 1 or 2 ltrs per 100kms in lieu of safety.

4WD Training 101Robert Peppers great book on 4WD essentials
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Reply By: CSeaJay - Wednesday, Oct 29, 2014 at 13:45

Wednesday, Oct 29, 2014 at 13:45
Batsy (and DMAX)
From my own experience, having ABS deactivated provides better stopping on a) corrugated roads, and b) hard dirt covered by a thin layer of dust/sand, and c) in sand.

ABS is better on all other surfaces specially slippery surfaces.

Having ABD DE-activated and braking on dirt where there is a layer of sand over, there is physically a build-up of sand in front of the wheel that becomes a 'wedge'. with ABS, the brakes let go as soon as there is lockup and drives over the 'wedge'

With ABS enabled, in some circumstances, (a), b) and c) above) it feels like I am on ice when I hit the brakes in an emergency (animal, oncoming car on blind track etc.)

I know I am not alone and know of others who pull out the ABS fuse when they are in above conditions.

CJ
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Follow Up By: Member - batsy - Wednesday, Oct 29, 2014 at 14:01

Wednesday, Oct 29, 2014 at 14:01
Thanks CSeaJay. Just spoke to a "tag along tour" operator at the local servo about this subject. He told me he advises those going with him amongst other things to be very careful on loose gravel & corrugated road with their brake distances as ABS doesn't "do everything". Note....he does not recommend disconnecting the system.
He told me of a number of instances where vehicles had had an accident or close encounter & the drivers thought the ABS should have "taken care" of the situation (He smiled at this comment).
Cheers
Batsy
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Reply By: The Landy - Wednesday, Oct 29, 2014 at 14:57

Wednesday, Oct 29, 2014 at 14:57
Any thoughts on the legality of disabling an important safety feature on the vehicle, or the view from the desk of the insurance assessor?

As I understand it all trucks and large trailers are required to (or soon will be) have ABS.

Cheers, Baz – The Landy
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Follow Up By: Slow one - Wednesday, Oct 29, 2014 at 15:30

Wednesday, Oct 29, 2014 at 15:30
Baz,
you are correct as most trucks and trailers run on bitumen.

They have to make it one size fits all when making it legislation. It will much safer for those trucks that are running bitumen roads. I will just be one of those things others that do a lot of dirt work will have to contend with.

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Follow Up By: Member - batsy - Wednesday, Oct 29, 2014 at 16:54

Wednesday, Oct 29, 2014 at 16:54
Baz, my take on the legality/insurance aspect is that if the vehicle has an ABS enclosed system (no disablement device included) & it could be proven that the vehicle had the ABS disabled at the time of the incident then the driver/owner would be legally liable & as such the insurance company would most likely dismiss the claim.
However my vehicle has a switch on the dash to turn the CDL on/off & this also does the same to the ABS.
Cheers
Batsy
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Follow Up By: Ron N - Wednesday, Oct 29, 2014 at 19:23

Wednesday, Oct 29, 2014 at 19:23
Big trucks obtain benefit from ABS as air brakes are notorious for a lack of feel when it comes to rapid braking.
Add in multiple sets of wheels which are all difficult to monitor individually through the brake pedal, and ABS therefore offers major advantages for big trucks and semi-trailers.
ABS still doesn't make up for the driving skills (or lack thereof) of the nut behind the wheel.
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Follow Up By: Pete Jackman (SA) - Friday, Oct 31, 2014 at 04:41

Friday, Oct 31, 2014 at 04:41
I had a chat to the tech services dudes at RAA after my first trip away in the Jackeroo when I had a scary experience with ABS on a hard dirt road covered in ball bearing gravel. They said that on some surfaces ABS is worse than useless. We discussed the legality of fitting a switch to disabling it and they said that it could be a reason for the insurance to disallow a claim.

They said that if I really wanted it off ion poor road surfaces, just put a blown fuse in the ABS slot. You wont forget it is off as there will be a warning light on the dash.

Cheers
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Reply By: Slow one - Wednesday, Oct 29, 2014 at 15:15

Wednesday, Oct 29, 2014 at 15:15
I'll put it simply and all can try for a result.

Drive 2 identical vehicles on a good corrugated road. One with ABS and one without. Now as we all do things safety and travel to conditions with our perceptive driving skills, we find a wash out that someone hid from us, I suspect they used kryptonite. Now we have to pull up quickly as our perfect driving didn't foresee the washout due to our X-ray vision being blurred by the kryptonite.

Approach the washout with both vehicles and just see which one stops first. I know the answer, as I am impervious to kryptonite and wouldn't have to brake for it in the first place.

Better still cow walks out on road, I know, I know drive to conditions. I sang out to the co but the cow just answered MOO, Which translated means, I hope you don't have ABS brakes in that bucket of bolts.

Better still, is the hidden one lane bridge with corrugations leading down to it, eyes widen as you see the approaching vehicle just about onto the bridge.

Some may change their mind about the use of ABS braking systems in these circumstances.
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Follow Up By: Slow one - Wednesday, Oct 29, 2014 at 15:39

Wednesday, Oct 29, 2014 at 15:39
Now to stop us hitting another vehicle, taking out a cow and destroying a front end, I had a look around (wonderful thing this google).

Link. ABS results on different surfaces.

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Follow Up By: olcoolone - Wednesday, Oct 29, 2014 at 18:27

Wednesday, Oct 29, 2014 at 18:27
Yes in a controlled condition a non ABS vehicle can stop in a shorter distance ..... but most accidents are not in controlled conditions plus the drivers reflexes and abilities are different.

For everyday use ABS is great.

BTW ABS was never intended or designed to lessen the stopping distance but to help keep the vehicle in control to steer around and avoid the obstacle.
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Follow Up By: Bob Y. - Qld - Wednesday, Oct 29, 2014 at 21:05

Wednesday, Oct 29, 2014 at 21:05
Thanks for the link, Slow.

George Foessel came out to Brighton Downs some years back, probably late '90's, and put the staff through a 4wd training course. Good bloke, lot of experience and excellent training methods.

Staff reckoned he was good too, as they were able to "fang" around without me getting up them. Did much of the stuff that he mentions in the article, cadence & threshold braking, bit of off road stuff. Even picked up a few skills myself, and no one had to worry about ABS either. :-)

Bob


Seen it all, Done it all.
Can't remember most of it.

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Follow Up By: Slow one - Wednesday, Oct 29, 2014 at 21:27

Wednesday, Oct 29, 2014 at 21:27
olcoolone,
what I am saying is that ABS on a corrugated road is down right useless when trying to pull up for an obstacle.

On corrugated dirt roads having no ABS is far better, as for the driving most do ABS is far better.

Yes, ABS was designed so as to be able to steer and brake, but it also has it's down side on dirt and the graphs show it. Controlled or uncontrolled the result will always be the same.
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Follow Up By: olcoolone - Wednesday, Oct 29, 2014 at 21:37

Wednesday, Oct 29, 2014 at 21:37
Slow one..... Correct, but people travel greater distances over non corrugated road then corrugated roads.

Corrugated roads bad enough to affect ABS would be in the 0.000000004% for the average driver and then having the need to apply the brakes in an emergency would bring it to 0.00000000000000000006% for the average driver. LoL

Like anything you drive to tne conditions, ones ability and the vehicls ability....... Too many want to find excusses so the don't have to blame themselves.

If I have to hit the brakes hard enough to make ABS dangerous over corrugations then I'm going to fast and it's my fault..... Not the fault of the ABS.
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Follow Up By: Slow one - Wednesday, Oct 29, 2014 at 21:59

Wednesday, Oct 29, 2014 at 21:59
Olcoolone, thanks for the scientific study that shows the percentage that drivers have problems with abs on corrugated roads. LOL.

I don't think anyone is trying to find excuses, at least i'm not. ABS on corrugations is horrible even emergency stopping at 40kph.

Drive to conditions is a phrase used after an incident to cover everything in the automotive world when things go wrong, it shifts blame until they investigate what the real CAUSES were and they can be many, including not driving to the conditions.

On a corrugated dirt road, give me a NON ABS vehicle anytime.
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Follow Up By: Slow one - Wednesday, Oct 29, 2014 at 22:00

Wednesday, Oct 29, 2014 at 22:00
Bob Y,
You are on the money about learning new things. I have done defensive driving courses and I always learnt something that helped me be a better driver. Serious me.


Not so serious me. Others have complimented me by saying I am not hopeless anymore and have moved up to just below average. Not bad hey.

The best thing I ever learnt, was how to get someone in 40 degrees heat to show you how to change that inside tyre, that has wrapped itself around everything after it let go. LOL.
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Follow Up By: gbc - Thursday, Oct 30, 2014 at 11:58

Thursday, Oct 30, 2014 at 11:58
I've also done a few 4wd courses with George Foessel in the 90's when he did our remote area training for AMSA each year.
A smart guy with people skills.
Good to see his results back up what we have all said about abs offroad.
He also backed me up when I killed the diffs in one of our first 100 series in the country (must have been 97 then). They were already giving trouble in the mines too. Of course the upper management suspected silly buggers and were on a witch hunt. It was good to throw it back at them.
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Follow Up By: Member -Ted (Vic) - Thursday, Oct 30, 2014 at 12:00

Thursday, Oct 30, 2014 at 12:00
Ocoolone
A millsecond is 1/1000 of a second not 1 millionth that is a microsecond. Just in case its important.

cheers
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Reply By: mikehzz - Wednesday, Oct 29, 2014 at 18:38

Wednesday, Oct 29, 2014 at 18:38
I'm feeling inadequate here. I have a very sophisticated car with all the latest gizmodery. I can turn the traction control off, the hill descent control off and the stability control off.....but I don't have a switch that disables the ABS. Could it be that people are confused what ABS is? I did lose ABS once when a wheel sensor got damaged and I could probably pull a fuse on it.
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Follow Up By: olcoolone - Wednesday, Oct 29, 2014 at 21:40

Wednesday, Oct 29, 2014 at 21:40
Quick sell it before you loose your driving skills, or do what I'm going to and go to the dealer tommorrow and get all the safety driving aids removed. .....

EO offers a wealth of good advice and information.

Do you think I should get the seat belts removed to?
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Follow Up By: John and Regina M - Wednesday, Oct 29, 2014 at 21:53

Wednesday, Oct 29, 2014 at 21:53
EO is full of experts in bull bleep .
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Follow Up By: mikehzz - Thursday, Oct 30, 2014 at 07:54

Thursday, Oct 30, 2014 at 07:54
My point was that very few cars have an ABS disabling switch, yet half of EO seems to be turning it off at will. What, are they all getting out and pulling a fuse? You can disable stability and traction control at will but the ABS still works with those disabled.
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Follow Up By: gbc - Thursday, Oct 30, 2014 at 12:03

Thursday, Oct 30, 2014 at 12:03
Correct - open bonnet and pull fuse.
I haven't done it on any of my last 4 vehicles. (Last 2 automatically switch it off in low range - hint hint)
My current vehicle (ranger) needs traction control switched off manually to go ok in sand.
Current abs is leaps and bounds better than the early stuff.
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FollowupID: 827071

Follow Up By: Bludge - Thursday, Oct 30, 2014 at 15:06

Thursday, Oct 30, 2014 at 15:06
Mikehzz,

I wouldn't worry too much, as soon as you activate the centre diff lock or engage 4WD in a part time 4WD the ABS turns off. High or low range.

As soon as the drive is 50/50 ABS cannot fully function to give individual wheel braking or safe steering. However as the front an rear are connected the braking is enhanced off road instead of 80/20 its 50/50.

Anyone who has done a 4WD course SISODRV302A or RIIVEH305A or Low Risk SISODRV205A will know this.

If people don't engage 4WD on corrugations or loose surfaces then ABS will do what it does.

In my vehicle, I always lock the centre diff as well as let down tyres and reduce speed on these types of road.
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FollowupID: 827085

Follow Up By: mikehzz - Thursday, Oct 30, 2014 at 20:11

Thursday, Oct 30, 2014 at 20:11
The ABS in my Jeep is still working with the centre diff locked and in low range. I can feel it shudder the brakes quite often especially on rough down hill tracks. That car has no traction control or hill descent either. My Landrover in sand mode, which does lock the centre diff, and with stability control off, a necessity on sand, will still activate the anti lock brakes under some conditions. The ABS kick in is unmistakeable and almost identical in both cars.
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FollowupID: 827098

Follow Up By: gbc - Thursday, Oct 30, 2014 at 20:56

Thursday, Oct 30, 2014 at 20:56
I don't know what car you have bludge or what courses you've done, but last I checked abs was connected to the brakes mate, not the driveshafts and I don't know of any mainstream fourby which turns off the abs automatically in high range 4wd unless it can be specifically disabled.
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FollowupID: 827099

Follow Up By: Bludge - Friday, Oct 31, 2014 at 12:35

Friday, Oct 31, 2014 at 12:35
Thanks GBC,

Bear with me a second, ignore ABS for a just a moment.

In high range 4WD, emergency stop foot on clutch, if both front wheels lock up, what happens to the rear, do they turn or lock up?

While the brakes may be on the wheels, those wheels are connected to a prop shaft that when in 4WD is connected to the rear prop shaft and in turn the wheels
If the front prop shaft is not turning the rear one is not turning either.

With ABS on in 4WD ABS would have to release all 4 wheels (3 at least). Resulting in no brakes at all as long as the prop shafts are not rotating.
If the prop shafts are turning one front and one rear will always turn at the same speed, rendering the ABS unable to independently brake each wheel which it is designed for.

In high range 4WD the vehicle relies on slippage to prevent wind up, ABS does not like slippage as it monitors all 4 wheels for traction, lockups and slippage.

If ABS is left on for high range 4WD why take it of just to change to low range? surely ABS high or low range changes nothing? Or what is different or what changes in ABS when travelling at 80 in high range 4WD to 20 in Low range 4WD?

Mikezz with regards to the brake pulsating in high range 4WD.

Quote "Some manufacturers saved the money and did not offer ABS at all on part time 4WD. On some vehicles a warning will flash that ABS is not working properly when in part time 4WD (Mercedes G-Class) - others offer no warning and the familiar pulsating of the brake pedal indicates that ABS is working. Well, its not."

but don't believe me, for a full explanation check here.


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FollowupID: 827141

Follow Up By: gbc - Friday, Oct 31, 2014 at 14:05

Friday, Oct 31, 2014 at 14:05
Yep, no argument.
The reality however, is a 100 series cruiser towing a trailer on Fraser, leaving Orchid beach and heading on the Wathumba track out past the old Rangers hut.
Casually cruising down the sandy hill and a ranger's ute casually appears around the corner.
Without a word of a lie it took a good 4 to 6 seconds to casually roll down that hill, me with both feet on the brake pedal, and bounce into his bullbar. The abs basically stole my brake pedal. One wheel loses traction, the brakes let the bloody lot go.
Like I said prior, this has been largely rectified on more modern vehicles, but I have first hand experience with having control of a vehicle taken from me in a situation which should never have been so. I also had it happen pulling up the trailer in the rain on tarmac with that same series of vehicles.
Just to confirm, I absolutely love having acronyms (abs, ebd etc etc) but some of the early stuff had pretty big holes in it's cloak of armour.
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FollowupID: 827155

Follow Up By: mikehzz - Friday, Oct 31, 2014 at 19:38

Friday, Oct 31, 2014 at 19:38
I don't see an issue. If the diffs are locked, then either both ends of the locked diff will stop rotating and the ABS will release both wheels at the same time, or they won't lock up at all and the ABS will do nothing. It wouldn't be possible for only one end of the locked diff to stop rotating.
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FollowupID: 827167

Reply By: Member - Andrew - Wednesday, Oct 29, 2014 at 22:04

Wednesday, Oct 29, 2014 at 22:04
Manufacturers calibrate the aggressiveness of their ABS intervention according to their own ideas on what they want to achieve.
A simple ABS can release the brakes when a computer receives a signal from a sensor that indicates a wheel has stopped turning. A complex complex system releases the brakes when a computer calculates that multiple sensors signals indicate a wheel is slowing faster than the others. Improvements in sensor and computer systems have allowed better modulation to hold the the wheel deceleration rate at the maximum traction point.
Complex systems are what we universally have in modern cars.
ABS was originally designed to stop aircraft from destroying tyres. Vehicle ABS was introduced to maintain steering control. That is drive around the problem, don’t slide into it.
The actual stopping distance is still directly related to the traction available at the road/tyre interface.
All good value and works brilliantly on hard surfaces by maintaining steering and potentially achieving the shortest stopping distance possible. Remembering that the vehicle systems came out of Europe where dirt roads are uncommon but rain and snow on bitumen isn't.
Emergency braking on loose gravel or sand, introduces the wedge effect. A locked wheel builds up a wall of the loose material in front of it that effectively improves the grip of the tyre to the road surface. That is a vehicle stops faster on loose gravel with the wheels locked. You see this being used effectively in gravel traps at race tracks.
Introduce ABS and the brakes are released allowing the wheel to roll over the wedge and lose that grip, resulting in longer stopping distances. So, steering control was maintained at the expense of stopping distance.
Early systems calibrated for bitumen could be scary on gravel because there was a perception of no braking at all. It wasn't true BUT vehicles were arriving at corners faster than non ABS vehicles.
Eventually calibrations were revised on some vehicles for countries like Australia. Smarter systems allowed less intervention and cleverer balance across all wheels meaning stopping distances reduced while steering control was maintained.
So, on newer vehicles, ABS works better on dirt than on older vehicles. The total effectiveness varies with the design of suspension systems, brake configurations, vehicle design and loading and how the driver reacts to what is happening.
You must still drive to the conditions. If you have never triggered your ABS then go and find somewhere safe to set it off and see what your vehicle reaction is. Knowing what happens may stop you from taking your foot off the brake when the system activates in an emergency.
Hope this helps

Regards

A
AnswerID: 541063

Reply By: Sand Man (SA) - Thursday, Oct 30, 2014 at 07:34

Thursday, Oct 30, 2014 at 07:34
Whether a vehicle has ABS or not, it comes down to the driver's experience in bringing the vehicle under control in the shortest distance, in a safe manner.
One of the best thing I did as a driver was to be involved in a Driver Safety Course. That was many years ago but the memory and practices learned during that course are still with me today. The skill is to learn how to stop in the shortest distance, without locking the wheels and enabling steering to operate at the same time.

I prefer automatic gearbox vehicles and have use my left foot to brake from way back in my Go-Kart racing days. I have far greater control over the pressure applied with my left foot than if I use my right. That is because I continually drive that way and the body's muscle control gets used to that method.
Now I can certainly drive a manual vehicle and adjust accordingly, but not to the same extent as a can using the left foot. It is quicker to actuate the brakes if the left foot is free from other functions and I can apply them almost as effectively as a vehicle that has ABS.

My last few vehicles have had ABS and I am a true believer in their effectiveness, under all road surface conditions, to bring the vehicle to a braking stop in the shortest possible time and with minimal loss of grip while still enabling steering control.
That is what the Safety Driving Course instilled in me. How to apply the brakes in a non-ABS equipped vehicle to the point af lockup, but not beyond it.
All participants in the course hit the pedestrian mockups at the start of the day and all participants passed the course at the end of the day.
As well as brake and steering control, it was the greatest eye opener on vehicle speed and whether you could stop in time, based on the speed you were doing.

I would recommend such a course to anyone who has not done one. It may well save your life as well as other peoples.

Bill


I'm diagonally parked in a parallel Universe!

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AnswerID: 541069

Reply By: Jackolux - Thursday, Oct 30, 2014 at 20:56

Thursday, Oct 30, 2014 at 20:56
All the electronic safety features on new cars today has to be a good thing for the vast majority of drivers . I was driving long before I was old enough to get a licence , grew up in the bush on a farm .
Most kids today don't get a chance to even do a wheelie , it's called hooning and the car is impounded .
I ride a powerful road bike that has ABS , I often practice emergency braking activating the ABS . That still dosent mean in a panic situation I will do the right thing , I hope it will give me a better chance .
Those the reckon they are better drivers than average and think they are better than all the electronic stuff , Unless you race V8 Super Cars every other weekend , I really doubt it .
I have never crashed a car , minor scraps only , sure have had a few near misses especially on the bike where I have done the right thing , good driving / riding , yep I'm a bloody legend , he'll of a lot of luck involved as well .
AnswerID: 541088

Reply By: JR - Friday, Oct 31, 2014 at 17:26

Friday, Oct 31, 2014 at 17:26
Having driven same vehicles, Nissan Patrols, for around 1 million km, throughout regional australia. Probably 50%+ on dirt roads, some with and some without ABS. On loose gravel and slippery clay roads, it can be truely dangerous.
You simply have no brakes at all in some situations, corrugations is a good example, locked wheels will absolutely stop you the fastest. Steering aside if you hit the roo, truck, table drain etc slower it is safer.
Now I wouldnt have a vehicle without it, but there does need to be a way to legally isolate it in special situations. Maybe flashing warning light etc.
AnswerID: 541141

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