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Old 19th September 2011, 15:38   #301
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Default Re: Driver ignorant of how ABS works; Turns Chevy Captiva upside down

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Originally Posted by honeybee View Post
Samurai, are you sure the decision to swerve was deliberate, or just a reaction/reflex?
Hope you are not doubting just because it was a she... No, I have the habit of watching rear view mirror while braking on road, so that I can compensate if the rear car doesn't respond on time. It has saved my butt few times. Here there was no chance to compensate, so I watched in horror as the rear car came hurtling at me, then I saw the lady turn the wheel frantically to avoid the crash.

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The point the OP and some others are trying to spread is we need to be ready for using the new safety features in our cars, and that means planning and practising. So is it a better strategy to brake and swerve, or to just brake or to just swerve? If we could plan it and practise it, we could actually put it to good use during an emergency.
Purpose of ABS is to allow you to brake & swerve at the same time. Don't need to choose between them.
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Old 19th September 2011, 15:45   #302
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Default Re: Driver ignorant of how ABS works; Turns Chevy Captiva upside down

I have a question.

In a non-ABS car but having power-steering, if you stand on the brakes and you steer.

Wont it steer?
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Old 19th September 2011, 15:57   #303
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Default Re: Driver ignorant of how ABS works; Turns Chevy Captiva upside down

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Originally Posted by Spitfire View Post
I have a question.

In a non-ABS car but having power-steering, if you stand on the brakes and you steer.

Wont it steer?
Depends on whether your wheels are locked or not. Standing on wheels doesn't always induce locking, it depends on the traction available.

Damn, as an offroader, you should know this.
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Old 19th September 2011, 16:05   #304
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Default Re: Driver ignorant of how ABS works; Turns Chevy Captiva upside down

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Originally Posted by Spitfire View Post
I have a question.

In a non-ABS car but having power-steering, if you stand on the brakes and you steer.

Wont it steer?
The front wheels will turn. But you have no control on the direction if the wheels lock up.
Also if the vehicle stalls, the brakes and the steering may fail as the engine must be on for them to function.

However, I don't believe in brake+clutch.
I would not hit the clutch till I have no choice and engine stall is going to happen.
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Old 19th September 2011, 16:16   #305
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Default Re: Driver ignorant of how ABS works; Turns Chevy Captiva upside down

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Originally Posted by Samurai View Post
Depends on whether your wheels are locked or not. Standing on wheels doesn't always induce locking, it depends on the traction available.

Damn, as an offroader, you should know this.
I do know by practical application. But I have never had an ABS car. Driven a few but then I am mighty conscious and never ride them hard.

But I was reading all the posts and got really confused.

So if the wheels are locked (vehicle still sliding - off road experience) and I steer using a Power-Steering. The car would still steer. Right? Why then does the ABS get blamed?

No offroader I have driven ever had a power-steering or ABS. So no way of making out how that would work.

Basically for me. ABS or No-ABS, physics is a b****. Try going against it and you have had it.

Quote:
Originally Posted by bblost View Post
The front wheels will turn. But you have no control on the direction if the wheels lock up.
What about if it is power assisted?

Quote:
Also if the vehicle stalls, the brakes and the steering may fail as the engine must be on for them to function.
The engine wont stall immediately. Not in the new-gen cars anyways. If it does the brakes would go first.

Quote:
However, I don't believe in brake+clutch.
I would not hit the clutch till I have no choice and engine stall is going to happen.
Panic braking is brake only.

I believe the driver of that car got some things wrong.

1. He is not used to the dynamics of a tall vehicle.
2. He freaked out when the brake lever pulsated below his foot.
3. And turned the steering full lock.

And physics struck.

Last edited by Spitfire : 19th September 2011 at 16:17.
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Old 19th September 2011, 16:19   #306
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Default Re: Driver ignorant of how ABS works; Turns Chevy Captiva upside down

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Originally Posted by Spitfire View Post
I


What about if it is power assisted?
Nothing to do with it.
The wheels will turn and point in the direction you want them to go in.
But the vehicle will move in any direction it wants to.
Usually straight ignoring the turn direction of the wheels.
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Old 19th September 2011, 16:24   #307
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Default Re: Driver ignorant of how ABS works; Turns Chevy Captiva upside down

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Originally Posted by bblost View Post
Nothing to do with it. The wheels will turn and point in the direction you want them to go in.
But the vehicle will move in any direction it wants to.
Usually straight ignoring the turn direction of the wheels.
Hmm.. interesting. I doubt that though.

Wont the front wheels act as a pivot and topple the car instead of it going straight? ABS or NO-ABS. The rear mass/weight of the vehicle helping it.

Even sedans could flip like that.

I was taught. If you have to ever brake hard (i.e. stand on the brakes). See that all wheels are dead straight.

This is a huge situation off road.
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Old 19th September 2011, 16:26   #308
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Default Re: Driver ignorant of how ABS works; Turns Chevy Captiva upside down

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Originally Posted by Samurai View Post
Hope you are not doubting just because it was a she... No, I have the habit of watching rear view mirror while braking on road, so that I can compensate if the rear car doesn't respond on time. It has saved my butt few times. Here there was no chance to compensate, so I watched in horror as the rear car came hurtling at me, then I saw the lady turn the wheel frantically to avoid the crash.

Purpose of ABS is to allow you to brake & swerve at the same time. Don't need to choose between them.
Nah, since it was the other driver who swerved, I was wondering if she swerved without any specific thought and you mis-understood it to be a carefully planned and executed maneuvre.

Most cars in India are without ABS and will be so for a few more years, till the law mandates ABS as standard fitment. Even then the existing non-ABS cars will take a long time to vanish from the roads. So it's important to know in a panic braking situation if I should focus on braking or on swerving or on both. If each type of situation demands a different treatment, I would like to know each so I can practise.

By habit I look for space to swerve in case I have to brake in an emergency, and by habit if I sense there's no space to swerve I jam the brakes viciously. So the car would appear to swerve and then come to a halt, while I am fully aware of its movement. Someone might mis-understand it, since they don't know what is going on through my mind. There have been times where I have swerved and actually accelerated to get away from an obstacle.

However, if there are any 'set plays' in such cases, such as you are about to T-bone someone else, do you swerve and try to hit him sideways so as to avoid T-boning him?

I remember reading somewhere that up in the air, if two aircraft find each other in the opposite direction, each is supposed to take a right turn. So the rule of thumb is if you see another aircraft approaching you head on, you turn right. The other guy turns right too, and so you put a safe distance between each other. Are there any such thumb rules we can follow?
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Old 19th September 2011, 16:31   #309
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Default Re: Driver ignorant of how ABS works; Turns Chevy Captiva upside down

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Originally Posted by Spitfire View Post
So if the wheels are locked (vehicle still sliding - off road experience) and I steer using a Power-Steering. The car would still steer. Right? Why then does the ABS get blamed?


What about if it is power assisted?
bblost is right. Steering will only turn the wheels. If the wheels are locked, car won't turn, it just moves in the direction of the momentum. The car will change direction only if the wheels are turning.

As any wet trail offroader knows, you don't slam the brakes in a slippery trail. If you do, the wheels will lock and steering control is lost. In such places, move very slowly using lowest gear and even brakes if required. But never slam the brakes to arrest the speed in a slippery trail, you will lock the wheels and lose steering control. This I originally learnt in ice/snow driving, same rules apply there.

A Classic (pun intended) example here: https://www.team-bhp.com/forum/4x4-e...tml#post996255

Last edited by Samurai : 19th September 2011 at 16:38.
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Old 19th September 2011, 16:39   #310
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Default Re: Driver ignorant of how ABS works; Turns Chevy Captiva upside down

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Originally Posted by Spitfire View Post
I do know by practical application. But I have never had an ABS car. Driven a few but then I am mighty conscious and never ride them hard.

But I was reading all the posts and got really confused.

So if the wheels are locked (vehicle still sliding - off road experience) and I steer using a Power-Steering. The car would still steer. Right? Why then does the ABS get blamed?

No offroader I have driven ever had a power-steering or ABS. So no way of making out how that would work.

Basically for me. ABS or No-ABS, physics is a b****. Try going against it and you have had it.



What about if it is power assisted?

.

The wheels would turn more easily, left, and right.
all the while you'll continue to skid in a straight line..

A roliing wheel will be able to provide direction.
A skidding, none.
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Old 19th September 2011, 16:52   #311
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Default Re: Driver ignorant of how ABS works; Turns Chevy Captiva upside down

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Originally Posted by Samurai View Post
bblost is right. Steering will only turn the wheels. If the wheels are locked, car won't turn, it just moves in the direction of the momentum. The car will change direction only if the wheels are turning.
Quote:
Originally Posted by mayankk View Post
A roliing wheel will be able to provide direction.
A skidding, none.
Thanks guys that's what I was looking for. Exactly like it happens on slippery offroad trails. i.e. because the contact patch on the road of the tyre stays the same in a locked condition (loss of traction).

So now velocity being constant. (High enough to topple the Captiva)

Wont Full-Lock on a Captiva topple the car? With ABS.

Exactly like it happened above?
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Old 19th September 2011, 16:57   #312
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Default Re: Driver ignorant of how ABS works; Turns Chevy Captiva upside down

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Originally Posted by Spitfire View Post
Wont Full-Lock on a Captiva topple the car? With ABS.

Exactly like it happened above?
It won't lock with ABS.
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Old 19th September 2011, 16:58   #313
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Default Re: Driver ignorant of how ABS works; Turns Chevy Captiva upside down

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Originally Posted by Samurai View Post
It won't lock with ABS.
I think full lock here is steering turned to the limit, left or right.
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Old 19th September 2011, 17:03   #314
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Default Re: Driver ignorant of how ABS works; Turns Chevy Captiva upside down

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Originally Posted by mayankk View Post
I think full lock here is steering turned to the limit, left or right.
Oh, sorry about that. I guess it is possible, sudden 90 degree turn and tall body, it can happen.
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Old 19th September 2011, 17:13   #315
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Default Re: Driver ignorant of how ABS works; Turns Chevy Captiva upside down

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Originally Posted by mayankk View Post
I think full lock here is steering turned to the limit, left or right.
Thanks that's what I meant by full lock.

Quote:
Originally Posted by Samurai View Post
Oh, sorry about that. I guess it is possible, sudden 90 degree turn and tall body, it can happen.
I believe that's what happened.

Its human error. Simple.

ABS does not consider that the driver is a moron.
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