ABS

[Astraist]

No that's not what StressedDave said. He was suggesting you need to keep the pressure on the pedal (and not instinctively back-off) to ensure the ABS maintains maximum possible braking.

Obviously.

I was just trying to elaborate on that.

I admit I never experimented this point in "scientific" conditions, but logic dictates that it will have some effect, whether negligible, on the stopping distance.

If you press the clutch, for instance, in hard braking with ABS working, the ABS will pulse faster and the stopping distance will be reduced. A similar effect will be achieved, theoretically, by squeezing down on that extra inch of pedal travel.

[jont]

1. De-clutching is a good idea, not because it increases the ABS pulse rate (it doesn't, that being a function of the hydraulics in the controller block) but because, like letting go of the steering wheel it removes any unhelpful inputs from the engine into the system.

I guess this is an ABS vs non-ABS thing then? I'm sure I remember on a Walshy day being told for an emergency stop not to de-clutch until the last possible second (but in an S1 Elise without ABS).

[TheInsanity1234]

1. De-clutching is a good idea, not because it increases the ABS pulse rate (it doesn't, that being a function of the hydraulics in the controller block) but because, like letting go of the steering wheel it removes any unhelpful inputs from the engine into the system.

I guess this is an ABS vs non-ABS thing then? I'm sure I remember on a Walshy day being told for an emergency stop not to de-clutch until the last possible second (but in an S1 Elise without ABS).

It's interesting, because if you leave the clutch in, then you might get a slightly shorter stopping distance, because of engine braking providing that marginally faster deceleration, however, de-clutching is a good idea, because if you make a mistake and press on the accelerator, the braking distance won't change as you've disconnected the engine anyway.

[trashbat]

2. Squeezing down that extra inch does nothing - once the ABS is working, the foot pedal is disconnected from the braking circuits.

I'm confused by this.

Let's say I'm on ice, and I apply light pressure to the brake pedal. I expect to activate ABS and get pulsed light braking.

Let's also suppose I'm on the motorway, and about to rear-end a truck, so I apply maximum pedal force. If I activate ABS I expect to get pulsed maximum braking.

Am I wrong about part of this?

[fungus]

1. De-clutching is a good idea, not because it increases the ABS pulse rate (it doesn't, that being a function of the hydraulics in the controller block) but because, like letting go of the steering wheel it removes any unhelpful inputs from the engine into the system.

I accept the above, but surely if the declutching is done before the driver is on the brakes, then the stopping distance will be marginally increased as the short period of engine braking that's available while the driver moves their foot from the gas pedal to the brake pedal, will be lost.

[Mr Cholmondeley-Warner]

Going back to the Car Limits video of the journalist being coached by Mark Robins, they were definitely avoiding ABS activation, and achieving very impressive reductions in stopping distances. Now I don't know what the differences would be _with_ ABS, but it must surely remain the case, that a system which is permanently applying retardation must be capable of stopping quicker than one which is pulsing the effort, regardless of the undisputed benefits of the pulsing system. Dave?

[zadocbrown]

But how many attempts did they need to beat abs? What you can do after practise and in response to an expected stimulus doesn't compare with a real world emergency.

Also, abs can differentially brake wheels depending on which have the most grip - something a driver can't do.

I guess in theory under perfect conditions a driver could be quicker without abs. But in the real world trying to be clever will more likely mean you take longer to stop, either because you didn't get it just right, and/or because conditions worked against you.

It's a matter of probability, and the quality of modern technology means it will beat even a skilled driver most of the time.

[cupraray]

The number of people who are driving around and have never activated ABS (as part of a lesson) is startling.

Surely it should be demonstrated to learner drivers, and allow them to experience what it's like so when they're in a situation where they need ABS to cut in, they know what to expect.

I for one, never realised ABS makes a noise like a machine gun going off until my dad activated it (somehow, whilst going uphill on a slightly damp surface) on a single track road when we met some twit in a Disco going the other way at the speed of sound.

Also, I know the brake pedal will pulse when you activate ABS, and as Dave has said, you MUST maintain a high pressure on the pedal, etc.
But that's only because I enjoy learning about the various aspects of cars and driving, and I've taken the trouble to read guidances on driving etc.

I'd gladly bet you a tenner that a lot of my friends whom are 17 and driving wouldn't know what is happening when ABS is activated, thus panicking and releasing the pressure only to crash into what they were trying to avoid.

when you become an advanced driver,and I use that term loosely, you will realise that you will never have to use ABS , traction control, or ESP. Now ask me why

[zadocbrown]

The number of people who are driving around and have never activated ABS (as part of a lesson) is startling.

Surely it should be demonstrated to learner drivers, and allow them to experience what it's like so when they're in a situation where they need ABS to cut in, they know what to expect.

I for one, never realised ABS makes a noise like a machine gun going off until my dad activated it (somehow, whilst going uphill on a slightly damp surface) on a single track road when we met some twit in a Disco going the other way at the speed of sound.

Also, I know the brake pedal will pulse when you activate ABS, and as Dave has said, you MUST maintain a high pressure on the pedal, etc.
But that's only because I enjoy learning about the various aspects of cars and driving, and I've taken the trouble to read guidances on driving etc.

I'd gladly bet you a tenner that a lot of my friends whom are 17 and driving wouldn't know what is happening when ABS is activated, thus panicking and releasing the pressure only to crash into what they were trying to avoid.

when you become an advanced driver,and I use that term loosely, you will realise that you will never have to use ABS , traction control, or ESP. Now ask me why

I think that is false confidence. You should always be ready to use these systems if necessary. It should be a rare event but rarely is not the same as never.

[Mr Cholmondeley-Warner]

@Cupraray - When YOU become an advanced driver, on the other hand, you will realise you never stop learning, and appreciate that you might be grateful for those systems one day, without believing yourself to be above such things

[cupraray]

@Cupraray - When YOU become an advanced driver, on the other hand, you will realise you never stop learning, and appreciate that you might be grateful for those systems one day, without believing yourself to be above such things

Sir, you are obviously an idiot

[trashbat]

Sir, you are obviously an idiot

Out of idle curiosity, why do you turn up on here & elsewhere every few months and add a burst of short and usually strange posts? Last time you bumped an old thread to slag off my car. Are you sure you're OK?

[skodatezzer]

@Cupraray - When YOU become an advanced driver, on the other hand, you will realise you never stop learning, and appreciate that you might be grateful for those systems one day, without believing yourself to be above such things

Sir, you are obviously an idiot

I've driven with Mr. C-W on a number of occasions now. I can confirm that 1) he is an advanced driver and 2) he is not an idiot. On the other hand, I have yet to see you drive. Fancy an ADUK driving day sometime?

One of the good things about this forum is the general lack of trolling. Our Insanity1234 is a young person who isn't driving yet but has a passion for the subject, and the intelligence to ask good questions. I have no doubt that in time he, too, will become an advanced driver, as he is already displaying the correct mind-set, i.e. he will never stop learning, I believe. It would be a shame if he were to feel discouraged or patronised.

[TheInsanity1234]

as he is already displaying the correct mind-set.

Indeed, the correct mindset is: "I'm vastly better than everyone else"

[skodatezzer]

as he is already displaying the correct mind-set.

Indeed, the correct mindset is: "I'm vastly better than everyone else"

Behave yourself when I'm supporting you!!