ABS breaks

Submitted: Monday, Jan 24, 2005 at 20:53
ThreadID: 19740 Views:2714 Replies:12 FollowUps:10
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Hello all, I have never driven a vehicle fitted with ABS offroad but was told the other day that they can be dangerous when attemting to reverse down very steep slopes due to the lack of weight on the front wheels making them want to lockup all the time which I suppose the ABS wouldn't like and releases then reaplies the breaks resulting in a faster and faster decent. Any truth in this.
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Reply By: Member - Roachie (SA) - Monday, Jan 24, 2005 at 21:03

Monday, Jan 24, 2005 at 21:03
Thems the "breaks", mudness....

Now, as for "brakes".......that's different. (sorry, couldn't help myself)...

I have ABS on my GU and it is (IMHO) treachorous on gravel roads. So much so that I've installed a cut-out switch on mine. Travelling at around 80 klicks on good gravel and hitting the anchors is very disconcerting with ABS brakes....it feels for all the world like your brakes just ain't gunna work.

As soon as I hit the gravel, I flick the switch and the ABS light on the dash lights-up telling me that it is off. If you don't want to go to the effort of installing a switch, you can simply remove the fuse and it has the same effect.

I have never experienced the "backwards down hill and losing control" syndrome, but I can imagine that it could well happen with ABS.
AnswerID: 94717

Follow Up By: Tuff60 - Tuesday, Jan 25, 2005 at 01:23

Tuesday, Jan 25, 2005 at 01:23
I am with Roachie on this, for the road only, gravel roads are scary, wet clay is ten times worse. Had a borrowed GUII with ABS up in Mildura, after two minutes of driving on wet clay roads, I wish I could have turned the ABS off. Made the brakes almost useless. That said I wish I had ABS in the Cruiser for the black top, especially when towing in the wet.
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Reply By: Member - Captain (WA) - Monday, Jan 24, 2005 at 23:50

Monday, Jan 24, 2005 at 23:50
Hi Mudness,

I have a 2003 GU with ABS and reckon its the ducks nuts!!! I too was initially concerned about reports of ABS issues and was prepared to install a cutout switch like Roachie has done. However, after testing it on gravel, i reckon I couldn't stop as quick as I could with ABS - much to my suprise.

I have previously read that the Nissan ABS is about the best on gravel roads - it actually has quite a long "lock" time before releasing and then locking again. It has supposedly been tuned for gravel roads and offroading and has a different program than when braking on bitumen. How it senses this I don't know (maybe by decelleration times???) but bottom line is I am happy with its offroad performance. Perhaps earlier versions did suffer some of the probelms you mention, but it seems like the manufacturers have taken this on board and updated them accordingly.

Even if it did have poor offroad performance, i would never buy a new vehicle without ABS. Its one of those compromises i am prepared to make as I think ABS brakes are one of the best safety devices available. Airbags, seatbelts, crumple zones etc are only any good in a collision, ABS may prevent the collision!

I reckon it saved my wife and kids once when a vehicle on the freeway lost control at 100 km/hr, she was able to steer around them while on full brakes when they ended up in her lane after bouncing off a guard rail. Even though her people mover also had airbags, it was far better to have avoided the otherwise inevitable collision if she had simply locked the brakes up and skidded straight into them.

Cheers

Captain
AnswerID: 94758

Reply By: Member - muzzgit - Tuesday, Jan 25, 2005 at 02:24

Tuesday, Jan 25, 2005 at 02:24
I too have a GU with ABS. After the first few worrying moments, which I now know is like learning to drive, I don't have a drama with them. I can hear AND feel them working and have accepted that I need to change my off road driving habits slightly, just like I've had to adjust my ways after having a pokey FJ62, and now I drive a slow to respond 4cyl turbo diesel. Once you know the ins and outs of what you're driving, it's no drama's. As for the backwards stuff, I dunno ! Maybe I'll try it and let you know.

ABS on gravel isn't scarry at all !! You just have to realise that it's different to what you have been used to. When braking heavily, I can still steer the car, which is what they were designed for.

Cheers'

Muzz
AnswerID: 94763

Reply By: Gone 4by'ing - Tuesday, Jan 25, 2005 at 06:53

Tuesday, Jan 25, 2005 at 06:53
What you need to buy is a state of the art Prado Grande with DAT ( Driver Assist Technology ) ........ It incorporates DAC ( Downhill assist control ) and is the only vehicle to offer it in reverse as well. It in affect applies the abs hundreds of times per second to control the descent of the vehicle , you will rarely ever need it but it is there for the real tough spots.
AnswerID: 94766

Follow Up By: Squizzy - Tuesday, Jan 25, 2005 at 07:21

Tuesday, Jan 25, 2005 at 07:21
If it's there for the real tough spots, then you would never use it on your Prado.
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Follow Up By: Gone 4by'ing - Tuesday, Jan 25, 2005 at 07:45

Tuesday, Jan 25, 2005 at 07:45
I suppose.

Nothing is a tough spot to a Prado.
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Reply By: Rob from Cairns Offroad Training & Tours - Tuesday, Jan 25, 2005 at 07:21

Tuesday, Jan 25, 2005 at 07:21
If you learn the threshold braking technique you can brake effectively on a loose gravel road in an ABS car without activating your ABS. There is no need to disconect the ABS and risk having it swiched off when you realy need it. Cheers Rob
AnswerID: 94767

Follow Up By: Member - David 0- Tuesday, Jan 25, 2005 at 09:47

Tuesday, Jan 25, 2005 at 09:47
For those who don't know, the threshold braking technique is the human operated equivelent of ABS. In simple terms, the sensor being the human driving the car, easing off the brakes as he feels the wheels lock. Thus operating on the threshold of lock-up. The problem with the technique in ABS equiped cars, is that the feedback from the pedal is a bit disconcerting and can be confusing for someone trying to learn the technique.

In my opinion ABS on gravel roads is liability.
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Reply By: Baz (NSW) - Tuesday, Jan 25, 2005 at 07:39

Tuesday, Jan 25, 2005 at 07:39
My opinion is ABS is great aspecially going down big greasy hills, just plant your foot on the brake and shove it into 1st low and it will just crawl down the hill and the fact that when you hit the brakes suddanly they wont lock up the wheels and you still have control so as to swerve to avoid the object you slammed the brakes on for.

Baz.
AnswerID: 94768

Follow Up By: Gone 4by'ing - Tuesday, Jan 25, 2005 at 07:45

Tuesday, Jan 25, 2005 at 07:45
EXACTLY !!
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Reply By: beatit - Tuesday, Jan 25, 2005 at 08:52

Tuesday, Jan 25, 2005 at 08:52
G'day guys,

Also have a GUII with ABS and had a scary experience on a dirt road on the Cape. Towing a trailer we came up a liitle fast on one of the Cape's notorious "dips", really wanted to lock up the whole show, trailer and all (usually have the controller set a little higher to gain more braking in the trailer on dirt) but with the ABS there was no chance. Everything worked out OK but I would bet that if I was able to lock things up I would have hit that dip a lot slower.

It is easy to say for people to drive according to conditions and most of us do - that's why we have 4wd's, let tyres down, etc BUT we will always get caught unawares and our ability to deal with that determines the final outcome. So if you can reduce the impact speed then that has to be a good thing and I would think this would be better achieved without ABS on dirt/gravel roads.

Kind regards
AnswerID: 94779

Reply By: flappan - Tuesday, Jan 25, 2005 at 09:10

Tuesday, Jan 25, 2005 at 09:10
I like my ABS. Wouldn't be without it.

Haven't yet had a situation where its been a problem (fingers crossed).
AnswerID: 94782

Reply By: fozzy - Tuesday, Jan 25, 2005 at 09:11

Tuesday, Jan 25, 2005 at 09:11
mudness
have to say on bitumen abs is excellent safety feature but when off rd it can be extremely dangerous.
on the 100 series ifs model the abs is disabled when low range is selected but still would benefit from switch to disable in high range depending on conditions eg icy rds,gravel rds etc and when it kicks in let me tell u the heart starts pumping and u wish it wasnt operable-and when you compare to cars without abs you know the problem is abs and not the driver
mate had a challenger and nearly wrote it and occupants off because the abs wouldnt allow the wheels to stop-mitsibishi didnt want to know about the problem
it happened twice and the second time - i was actually passenger and lucky to be here-that trip down a hill backwards would not have happened if abs could have been disabled.
AnswerID: 94783

Follow Up By: Member - Camper (SA) - Tuesday, Jan 25, 2005 at 14:11

Tuesday, Jan 25, 2005 at 14:11
I respect the fact that you are telling the story and that you were there when the Challenger had the problem but I find it hard to believe. Did I get it right (before I take our Challa out for some testing)? He was reversing downhill and applied the brakes while still in low gear, as you would and the ABS would not let him bring the vehicle to a stop?
I was under the impression that ABS sensed a skidding wheel computed the forces necessary to stop it skidding while still applying braking force and got on with the job. The secret being: when the ABS does its thing, ignore the vibrating pedal and break harder.
Am I living in a fool's paradise again (still) or (as usual)?

Times I've experimented with ABS on gravel it has been fine.
Look forward to all answers with interest.
Thanks,
Camper
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Follow Up By: fozzy - Thursday, Jan 27, 2005 at 07:18

Thursday, Jan 27, 2005 at 07:18
camper
gp out and test your vehicle and you will find out what i mean-whether reverse or driving forward
im not talking about a gravel road where of course you stop by keeping the pedal pressed hard to floor i am talking about a descent of a steep greasy hill where the abs does what it was designed for and constantly senses a skidding wheel and wont let the car stop
try it on a flat muddy greasy slippery rd first to see what i mean.
you certainly need to be aware of abs limitations-its not a matter of going down any steep hill and thinking im fine i hit the brakes and the abs will stop me-thats is totally wrong to think that cos it wont happen
ps im not trying to bag the challenger-i would assume its the same with all abs equipped vehicles-in my 100 series it disables in low range but still causes problems in high range.in earlier 100s i dont think it disabled in low
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Follow Up By: fozzy - Thursday, Jan 27, 2005 at 15:38

Thursday, Jan 27, 2005 at 15:38
camper
sorry should make it clear im referring to wettish surfaces where slippage occurrs ie clay/mud/icy(snow)
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FollowupID: 353964

Follow Up By: Member - Camper (SA) - Thursday, Jan 27, 2005 at 21:35

Thursday, Jan 27, 2005 at 21:35
Thanks for your follow-up Fozzy.
I didn't think you were bagging the Challa and am not precious about it anyway, except in jest. All 4wd's have their limitations after all. I find this discussion of ABS facinating and will certainly do some testing and some further research.
In the descriptions you mention - greasy hills descent I wonder if an unassisted brake would be much better. I guess that tyre tread has a bearing on this too unless the tread is fully clogged with mud which would not throw out of the tread when going downhill slowly.

All grist to the theory of motoring mill which obviously many of us enjoy analysing.

All the best with it,
Camper
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FollowupID: 354035

Reply By: drivesafe - Tuesday, Jan 25, 2005 at 16:02

Tuesday, Jan 25, 2005 at 16:02
Hi Madness, I don’t care what anybody else says, turning your ABS off for driving on gravel roads is total lunacy.

I had 2 discos and the first did not have ABS, when I got the second, it was equipped with ABS and lucky for me, a mate, who use to test drive 4WDs for one of the 4WD mags, was with me the first time I went out.
He, thinking he was reminding me, told me to watch out for the brakes on loose gravel.
Not having a clue what he was on about, I asked him what he was talking about.
He then informed me that I would need up to a 3rd more braking distance if I went for full on brakes in the gravel.
This was the first I had heard of any “problem” with using ABS on a 4WD.
I’ll come back to this in a minute.

When ABS was first fitted to racing cars, the drivers were not impressed.
They thought they were loosing some of their brake control.
After a very short period of time they found that because of the ABS, they were able to reduce their lap times.

The reason for this is exactly the same reason why ABS on a 4WD is a major step forward.
With race car drivers, they found that before ABS they would have to brake hard before they entered a curve, against having ABS where they could leave their braking till later and be able to brake with much greater safety, if needed, in the curve, again allowing them to travel faster around the curve. Put simply, they had much much more control of the car at high speed and this brings me back to the 4WD situation.

If you are a very experienced 4WD driver then you won’t be going for the brakes full on in the first place. But if you are like me and the other 99.5% of 4WD drivers, you are far better off being able to steer your 4WD at 60 kph hopefully around a problem rather than sliding into it at 40 kph.
I’ll put it another way, if you are going to hit a very large tree and collision is unavoidable, you have a greater chance of surviving a head-on at 60 kph than if you skid side wards into the tree at 40 kph.

Also remember too, 4WDs, as you will probably be aware, roll at the drop of a hat so if you have control of your vehicle you have a far greater chance of keeping it straight and therefore, upright and ABS gives you much greater control.

The best thing you can do is find a large area of loose gravel and drive your 4WD to the point where you start to loose it. ONLY DO THIS AT LOW SPEEDS. This is the best way to not only find out how the ABS affects your control but it’s a great way to get a real life idea of how far you can actually push your 4WD with some safety.

Cheers
AnswerID: 94838

Reply By: MrBitchi - Tuesday, Jan 25, 2005 at 16:33

Tuesday, Jan 25, 2005 at 16:33
When you apply full brakes in a non ABS vehicle on soft surfaces the wheels lock and create a "bow wave" which helps slow the vehicle. An ABS equipped vehicle will not do this.
Personally I much prefer having the ability to lock the wheels when I want to, although I have'nt figured out how to wire a switch in the Paj yet.

Cheers, John.
AnswerID: 94846

Follow Up By: bigjon - Tuesday, Jan 25, 2005 at 23:01

Tuesday, Jan 25, 2005 at 23:01
Throw your handbrake on!
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Reply By: G.T. - Tuesday, Jan 25, 2005 at 17:58

Tuesday, Jan 25, 2005 at 17:58
For those who are not sure if disabling the A.B.S. system is wise or not , try a braking test on your favourite gravel road ( when no one is around and it is safe ) first with A.B.S. activated ( at a fairly low speed ) then pull the fuse and do another test without A.B.S. ( at the same speed of course ) and compare your results. Further tests could be done at increasing higher speeds as long as it is safe. The same stretch of road should be used for both tests. Just my thoughts . Regards G.T.
AnswerID: 94859

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