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Spinoff : ABS in reverse
(196 posts, started )
also, doesn't anyone has anything to tell about static/dynamic friction forces which i learnt while i was in highschool? i guess it should be talked about in such a long discussion going on abs and locking wheels and stopping distance and friction etc...
Quote from ice63de :Sorry but you are totally wrong!

ABS is very important on wet, icy and heavy snow. Because it allows to fully push the breaks without locking the tieres and you can still stear the car under breaking and reduce the chance to spin. The only disadvantage of ABS is a increased breaking distance in dry conditions.

You may mixed ABS up with ESP (DTC) on icy/heavy snow. ESP should be disabled in these conditions. Read your car's operating manual.

True ABS is good on the wet and dry(altought i've never experienced it even under heavy breaking situation(went to a race track with my mom's 06 civic) but on ice/snow it's scary, it feels like you don't control whats happening with the brakes and on ice it feels like the car will never stop. But i guess for an average driver they are still beter then normal brakes
my E30's ABS is working in reverse
Quote from The Stig PL :my E30's ABS is working in reverse

yeah why not, ABS got nothing to do with which way are you going or which gear you are on
in normal cars it is a separated brake system, in those new shitty full of electronic cars it is for sure connted with stabilisation system etc. and it that can apply brakes on its own... but never heard a thing of automaticswitching off ABS on reverse
Well Fiat Panda 1.2 (BJ 2006) - ABS works in reverse.
What a ridiculous argument this is.

Since most of you have no idea what you are talking about, I will clear some things up.

The anti-lock braking system is designed to help the driver maintain steering control under maximum braking by preventing the wheels from locking from excessive brake pressure in emergency situations. It is not designed to make you stop faster. Although on some surfaces, this is a side effect of the system. I won't go into specifics but it's all about forces, rolling and sliding friction, etc etc. On a dry asphalt road you'll stop faster with locked wheels. On a very wet asphalt road you'll stop faster with ABS. On ice you will stop faster with ABS. On very loose gravel, snow, mud etc, you will stop faster with locked wheels, and on these particular surfaces it will take what seems like a lifetime to stop with ABS.

Simply put, ABS is there to help you brake really hard and steer at the same time. It's not to stop you faster.

Yes ABS does work in reverse. But I don't see the need for it to. If you find yourself in a situation where you are going backwards fast enough to warrant the use of ABS then you've severly messed up somewhere, and in such a situation, locked wheels would probably help you more than ABS. Remember, ABS helps you brake and steer. If you're going backwards at 50mph, why on earth would you need to steer? You'd want to stop as fast as possible, and if you're in a spin, ABS will not help.

And the system does of course have its limits, as I found out the hard way when I may have taken a corner too fast on a country lane, I went into a spin and ABS could do nothing to help me, only the wall that I hit could stop me then. Situations like that are where you want ESP, to prevent the spin in the first place.
Finally, someone actually knows what they're talking about.

+1 to you mate.
I hope you're being ironic S14. If locking wheels was the fastest way to stop on asphalt, then all the fuss about cadence braking what would be? elitism?

Bullshit:

Quote from janipewter :On a dry asphalt road you'll stop faster with locked wheels.

Scientific reply to bullshit:

Quote :Track test data clearly shows that for most manoeuvres stopping distance are smaller in ABS-fitted than non-ABS fitted vehicles, particularly on wet or icy surfaces. Exceptions are on dry bitumen, where braking performance at higher speed (>35-50 km/h) with ABS is greater than locked wheel braking.(*)

Get over it, most of us will never be better than ABS and no amount of ABS bashing will change this. If you think you are the mythological skilled driver, go to a track and see for yourself - if you do not have the money for a trackday, that's not a good excuse to wrap yourself around a tree on a public road - you know innocent bystanders have the nasty habit to be around when shit happens.

Every sunday I could just open the newspaper and then post here the names of some kids who thought to be the new Schumachers. But really the only way they could get a headline with their driving is hugging that tree in their dad's car.

Quote from janipewter :as I found out the hard way when I may have taken a corner too fast on a country lane

ESP won't do naff if you go into corners too fast. The lesson to be learnt here is: drive slower, you never know what's behind the corner on a public road.

(*) excerpt from http://www.monash.edu.au/muarc ... ystem%20effectiveness.pdf
Quote from NightShift :blah blah blah

Quote :The anti-lock braking system is designed to help the driver maintain steering control under maximum braking by preventing the wheels from locking from excessive brake pressure in emergency situations. It is not designed to make you stop faster. Although on some surfaces, this is a side effect of the system.

Fact.
Quote from S14 DRIFT :Fact.

Ok, noone can argue that. But, in most of the situations, it does; it's a side effect, if you want to call it like that.
For us, normally experienced drivers that can't cadence brake (or that can in theory, but in an emergency stop panic and press the pedal to the floor), a car with ABS is just better, because it lets you go around the obstacle AND it makes you stop faster. Full stop.
Yup, and I never denied that fact. That said a while ago in Bike or RiDE (Motorcycle stuff I know :really, it had an experienced racer aboard 2 bikes. Both exactly the same (I think they were CB1000Fs), but one had ABS and the other didn't. The racer could stop quicker without ABS, but a normal road rider stopped faster with ABS, so it's just down to experience and feel.
Quote from S14 DRIFT :Fact. (It's not designed to make you stop faster)

The fact is ABS stops faster than most drivers on most surface types. A number of indipendent tests have been made over the years and the outcome is always the same.

ABS truly is 'electronic cadence braking', better performance hardly is a side effect or by-product. ABS was marketed in another way, true, but that's marketing, i.e. bullshit someone has to say to sell things better.

And mind you S14, I was not blaming you for missing the BS in the post above yours - actually I thought you were being ironic, this stuff has been going on for so long we're all sick of it.

My post was actually trying to make a broader statement about the ever-going 'ABS yes or no' argument.
I say ABS should be an option in LFS, but it should be realistic to the car, ABS on the starion (xrt/xrg) should be rear wheels only and single channel.

As far as the debate about what ABS is designed for, I already stated the facts, the REAL facts. ABS is NOT designed to stop your car, it IS designed to give you steering control/prevent spins.

On the starion the implementation of ABS was intended to prevent the car from spinning when you mashed on the brakes and turned the wheel, the front wheels could still lock if you realy pushed on the pedal, but the rears would not, allowing you to get maximum brake force from the front wheels without locking the rears.

The problem with that was that drivers would just mash the pedal and lock the fronts, so future systems included the fronts in the ABS system. A car stopping faster from ABS is a happy accident of the design and not its intended function.

I started this debate when I tried to tell people the truth about ABS, this is not something I just said because I belived it true, I learned this information while working on and learning about brake systems. Any experianced mechanic who has read the proper books on ABS systems will tell you exactly the same as I have. I have yet to find any book that says ABS is to stop the car faster, they all say it is designed to allow steering control in a panic situation.

As a note on that, NEVER listen to car dealers about what things in your car do, they will almost always give you wrong or incomplete information.

I realy hope people will listen to me, I have read the books, looked at the studies and talked to people with alot more knowlege/experiance about it than myself, and they all say the same.

Lets just put this one to bed people, shall we?
Well, VW Scirocco 1.4l 160hp TSI - ABS works in Reverse.
Quote from Mojo1987 :Well, VW Scirocco 1.4l 160hp TSI - ABS works in Reverse.

Scared the living sh*t out of the poor salesman/owner trying that out?
Maybe he bought one.
Yes i bought one. Got my car on friday and tested it out last saturday.
Can upload some pics if you would see my car

Edit:
Here there are already 2 pics in my racing teams forum. they want to paint my car in teamskins *scared*

http://forum.lightning-racing. ... =262&pid=4780#pid4780
Just for your information, ABS in LFS does work both ways.........I am a Reverse driver and
Quote :Erm, why would you want ABS in reverse, wether its in LFS or real life... Not like you race backwards... In real life maybe in snowy conditions it can be useful (even then lockups are easy to get) but in LFS where you're sopose to be racing or whatever I doupt you need ABS in reverse O_O.

Wait, after thinking about this, I just realised that it happened to me sometimes that I crash or something and while backing up and braking I lock up. But meh, not really THAT important.

yes i DO RACE/drive in reverse. That said, the system needs refining. Say i was travelling down a straight in reverse in a FZ5 at 220kmh..........i saw a car pull out from the grass and i swerved to avoid him. When it's time to brake, the car 's steering/body dynamics (i mean by body roll etc) not straight.......the rear wheels can start to lock, but the left/right wheels take turns to lock so the car seems to be wavering.......definitely need refining this system.
#172 - STF
Quote from Neoman15M :Just for your information, ABS in LFS does work both ways..

Shh, it did not, before this thread.
In my opinion the best way to learn cadence branking is to use a car that lacks the feature of abs. (Normally a car from mid-90's or older)
Take a wet road, a cardboard box (or similar to avoid damage), and a spot where there's no traffic and stuff to accidentally hit in case anything bad happens. Then speed up and try to stop as close to the box as possible, raising the speed each time to really learn what speed does with brake distance.

How I learned this technique is basically by not having ABS in my car (Volvo 440 2.0 '94) and as I tend to drive quite fast I've had some "training". The car is really lightweight, which makes it somewhat more difficult (in my opinion) to get any grip when braking on wet surfaces.

I think it's mostly a factor of panic or hesitation that prevents most drivers to not use the technique only because they want to stop as fast as they can. (Duh')
The only way to learn braking is in an 80's VW Polo.

Unstable front suspension with a single arm located by an ARB.
Boat like steering.
No ABS.
No vaccuum assisted servo.
Solid discs with single-piston sliding caliper up front (overheat really fast)
Drums at rear.

I love the ABS on my RX-7. It's really unobtrusive, and when you DO floor the brake pedal, you can hear the front wheels chirping right on the edge.

Not like my dads numb plastic feeling civilised Audi.
Quote from janipewter :What a ridiculous argument this is.
On a dry asphalt road you'll stop faster with locked wheels. On a very wet asphalt road you'll stop faster with ABS. On ice you will stop faster with ABS. On very loose gravel, snow, mud etc, you will stop faster with locked wheels, and on these particular surfaces it will take what seems like a lifetime to stop with ABS.

And the ridiculousness goes on. Dry and wet asphalt behave somewhat the same regarding slip ratio - braking force. The optimum is achieved with 10-30 % slip and there is a ~30% reduction in braking force with a locked tyre. This is reflected in a finnish test, where using non-studded winter tyres braking distance on dry asphalt increased from 32 m on ABS to 45 m on locked tyres.
On loose surfaces and ice, a locked tyre will yield a shorter braking distance.
On loose surfaces partly due to the tyre digging into the ground. Also in test conditions threshold braking on ice demonstrated significant gains over a locked tyre(191 m - 230 m). It is worth mentioning that in emergency braking situations nobody will be able to perform threshold braking to it's full potential.
www.autoshop101.com/forms/brake09.pdf
Here you go, page 3.

All of these test results are from straight line braking. While cornering ABS benefits from being able to control each brake individually to achieve the system's desired slip ratio. With conventional brakes, no matter who the driver is, you will be unable to do this due to different loads on each tyre and having only one pedal, d'uh

Quote :
Yes ABS does work in reverse. But I don't see the need for it to. If you find yourself in a situation where you are going backwards fast enough to warrant the use of ABS then you've severly messed up somewhere, and in such a situation, locked wheels would probably help you more than ABS. Remember, ABS helps you brake and steer. If you're going backwards at 50mph, why on earth would you need to steer? You'd want to stop as fast as possible, and if you're in a spin, ABS will not help.

I give you props for your logic 'ABS helps to steer'->'You don't need to steer while reversing fast'->'ABS will not help'. However that isnt the reality. There might be some buddhist thinking behind not needing to steer while reversing, but I'm not familiar with that religion.

The reason why ABS would be needed on reverse is simple. Due to brake bias of the car, which in traditional systems is achieved with a pressure regulator for the rear brakes, you will not get much brake force to the rear tyres that act as front tyres. You'll also lock up the fronts, causing tyres to loose their lateral traction and make you prone to spin. With ABS brakes more brake pressure can be applied to the rear brakes. This in combination with the front brakes not locking up (while reversing) will yield in a much shorter braking distance with much greater stability. Which, by the way, happens to be one of the key benefits of ABS: you will maintain directional stability even when one side of the car is on ice and the other on asphalt.

Oh and just my favorite quote to end this post:
Quote from janipewter :Since most of you have no idea what you are talking about, I will clear some things up.



Spinoff : ABS in reverse
(196 posts, started )
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