Winters here - Time to pull the ABS fuse

[1-3-2-4]

where is the G sensor on the 95 Legacy?

 

when my car got soaked inside I had to pull everything out to dry including the ABS computer under the passenger seat (it's at an angle between the seat and door seal) and the ECU.

 

I did open the case to dry it out (water got inside) but before I did that it was giving me a fit.. the best way I could describe it acting before it got dried out was the brake petal got solid as a rock and moving along at like 5 mph and just lightly tapping the brakes the wheel would skid.

 

Anyways I'm glad that's past and wont do that again

 

But anything here?

 

 

 

I've driven on some roads where the road got iced up.. and I guess if you get the brakes just right you can lock up all 4 and the ABS thinks the car is slowing down without skidding.

[Bad Brian]

Maybe you need new ABS wheel sensors ?

 

~Howard

 

Good reason not to have ABS, $200+ per wheel, and that is not at the dealer or with labor! DIY special and you are still broke.

[Setright]

Struct...the extra distance is dependent on the conditions, of both the road and the car.

 

Under normal braking, there is ZERO difference, since I assume you are not make emergency stops all the time.

 

So there is NO COMPROMISE in daily braking. But a major advantage in panic braking.

 

I will concur that studded winter tyres will stop more quickly on ice, when locked up so the studs drag in the ice. Here, the ABS would be good to shut off.

 

However, the example cited further above in this post discusses slush/snow, where a good winter tyre will not make dramatic increases in stopping distance with or without ABS.

 

 

 

Funny Story

 

The late and much-missed Leonard Setright attended the launch of the Ford Scorpio/Granada/Falcon. Said car was to be the first with ABS fitted as standard. Fancy stuff in 1984

 

Anyhoo, Leonard knew that Ford'e engineers had decided their system was "infallible" and would not let all the wheels lock up at once, so there was no need for an expensive g-sensor. The incoming wheel speeds would be enough.

Tearing around the test track, Mr. Setright then exploited this omission and stomped so suddenly and so hard on the brake pedal that all four wheels locked up.....squealing and sliding as the other journalists and Ford representatives looked on in surprise

 

He had the car on the limit of grip coming out of the final corner, just to be sure the tyres wouldn't have the added grip to provide braking power. The poor car thought it was standing still...and didn't cycle the brake line pressure.

 

 

Is it any wonder that I choose to keep his memory alive by "stealing" his name ??

[CNY_Dave]

Your problems stem from a combination of bad tyres and worn dampers/shock absorbers.

 

YES, in an ideal stop, the ABS will lengthen the braking distance moderately. City speeds, the difference might be 2-3 feet.

 

HOWEVER, in a panic stop, when a child runs in front of you, and you mash the brake into the carpet, the ABS will stop you, the NON-ABS will see you lock all four and slide onward.

 

It is a reality, in a panic, most of us just stand on the brake. I have participated in many advanced driving courses, and I am very confident in most situations, even some suprises, BUT a pedestrian that appears from nowhere still means standing on it. Sure, in some cases there may be space/time to release the brake and steer around, but again...panic does mean panic.

 

 

PLEASE CONSIDER THE AGE of your tyres also. 4 years and the wet/cold weather performance drops off. 5 years, and they are useless.

 

Look for 4 digits stamped in an oval. First two are week number, second two the production year.

 

0105 means first week of 2005....and those tyres are only suitable for the dump. Nevermind the tread depth.

 

Just because you haven't had it happen, doesn't mean it doesn't happen despite the best of tires and vehicle condition.

There are times when it happens because you're coming in a bit too hot, then there's times when the ABS will coast you along no matter how slow you're going- usually down a fairly steep hill.

 

Mind you I'm in the camp of leaving the ABS connected and just dealing with those few times the ABS wants to coast me down the hill by employing appropriate strategies.

 

 

Dave

[WRX2FFU]

We have had a lot of recent "abs" hate threads in my local forum. I don't really understand the hate.

 

I have driven and have cars with and without abs. My 02' wagon has abs and I have never had an issues with it at all.

 

All of my subies are sticks so I rarely use the brakes to stop in the winter unless I am going less than 5 mph so I have nevr had abs issues.

 

I do have good tires on all my cars though too.

[StructEngineer]

We received 4" of snow last night. Finally decided to pull the ABS fuse. Braking distances improved. Still not as good as the civic, but at least im not ABS'ing through the crosswalks.

 

Everything on the forester is in good working order so don't try to give me excuses that my tires are 10 yrs old or my shocks are bad.

[subaruplatt]

"Well, most of the cars I have owned have not had ABS, so I'm still not that familiar with it. I'm still surprised when I notice it kicking in and vibrating my brake pedal. I grew up in the days when you learned to slow down in advance of situations (the art of coasting up to a stoplight—and pissing off the guy behind you), and you pumped the brakes judiciously when you noticed a bit of a skid."

With abs the harder you have to stop the harder you push the peddle there is no pumping or feathering.

This doesn't abrogate common sense things like snow tires or speed reduction.

ABS just means that when you go into a slide that you will come out straight.

ABS has all but banished fish tailing.

Also one goal of ABS is by allowing limited slip is to distribute breaking across a larger area.

So with ABS you allow a little extra for a stop on sheer icy surfaces but will always stop straight.

 

I had a summertime highway incident once with ABS.

The car in front of me had slammed into a stopped car in front of him and I was about to become the 4th car in the Pile up.

In this situation there was no way I could ever have stopped in time.

What ABS did when I remembered to use it properly was give me the option to drive on the side road and and around him.

Without ABS I could never have steered around.

 

And yes I use snow tires in the winter and as a consequence never even see ABS.

Also my 4 year old summer tires are useless now for rain in the summer .They would be doubly useless once the temperatures drop.

New tires contain silicon and silica and they are light years beyond what we were used to previously.

Even snow tires can be expected to ride nicely on the highway these days and finally they have become almost as good as summer tires.

Edited February 10, 2010 by subaruplatt
more thoughts

[1bignose]

dose anyone know how abs works? do you know what tires kick in. Do you know there many different types of abs. you guy know why the pedel puses when the abs kicks in. when the abs is not actvated its like not having abs which is like your day to day driving. most abs in (newer cars) dont kick in tell one or more tires start to lock up, when it locks up the wheel senter actvateds the abs pump witch is like a on and off switch for your brakes,thats why your pedel puses. now the time that i have found when the abs dosent work right is when someone dose brakes and they go to bleed the brakes, and dose not do it right. if you have air in your abs pump its not going to work right.

 

so you guys know the pump actvateds as little 2 tires at a time or all 4 tires. so if the front right tire locks up in mud snow , the abs will primerly actvated that front right and the left rear that way it keep the car where you aim. go to a gravel road hit your brakes and you will fill the abs pump kick and you can hear the pump to, get out and look at the gravel where your tires were then do the same with a car without abs and you can see how abs can help you.

when you lock up your tires you will start to faster also when you lock up your tires you cant turn

 

so this was a small run down of abs there is alot more to it

it dose help

[Setright]

Struct, we are not making excuses, but trying to give good advice suggestions

 

Hard to tell if we agree on what a "good" tyre is. Continental TS 810 or 830 are amazingly capable on compacted snow, and not to shabby on ice.

 

 

If you don't want the ABS to come on, brake progessively. Squeeze the pedal slowly as you would/should a non-ABS system. Let the front tyres dig in as the weight transfers and press ever harder up to the point of locking.

 

Don't pull the fuse

Edited February 10, 2010 by Setright

[JohnKos]

We have had a lot of recent "abs" hate threads in my local forum.

 

It's not hate, it's severe dislike.

[hankosolder2]

Well, the simple fact is that cars equipped with ABS have essentially equal (actually slightly higher) crash rates than cars without. All sorts of explanations have been given (drivers are scared by the pedal feedback and back off, people compensate for the 'added safety of ABS' by driving faster etc.) I think it's just not as great a boon as one would think.

 

The simple fact of the matter is that sometimes stopping in the shortest distance (& or spinning out) is better than maintaining directional control. Generally in an evasive situation, most drivers choose one strategy (i.e. swerve OR brake.) I honestly can't recall a situation where I felt the need to do both simultaneously.

 

The things which vex me are a.) that it's not switchable b.) the threshold speed is set way too low...it should cut out below 10 mph, not 5mph. c.) too sensitive to bumpy surfaces d.) too sensitive to worn shocks/struts.

 

 

Nathan

[CNY_Dave]

Well, the simple fact is that cars equipped with ABS have essentially equal (actually slightly higher) crash rates than cars without. All sorts of explanations have been given (drivers are scared by the pedal feedback and back off, people compensate for the 'added safety of ABS' by driving faster etc.) I think it's just not as great a boon as one would think.

 

The simple fact of the matter is that sometimes stopping in the shortest distance (& or spinning out) is better than maintaining directional control. Generally in an evasive situation, most drivers choose one strategy (i.e. swerve OR brake.) I honestly can't recall a situation where I felt the need to do both simultaneously.

 

The things which vex me are a.) that it's not switchable b.) the threshold speed is set way too low...it should cut out below 10 mph, not 5mph. c.) too sensitive to bumpy surfaces d.) too sensitive to worn shocks/struts.

 

 

Nathan

 

Fully agree on the lower threshold speed. 20mph would be perfect.

 

Mine does not seem to be sensitive to bumps, fortunately.

 

It's very easy to make switchable, of course.

 

Dave

[1bignose]

fact is if you dont lock up your tires abs sould not come on

 

one from subaru abs test

 

 

http://www.youtube.com/watch?v=jZzdyH8ethY

[CNY_Dave]

fact is if you dont lock up your tires abs sould not come on

 

one from subaru abs test

 

 

http://www.youtube.com/watch?v=jZzdyH8ethY

 

The key here is that sometimes the best way to stop is to lock 'em right the heck up. The ABS won't let you stop, but locking the tires up stops the car almost instantly. The circumstances where this happens do not occur every day, but regularly enough that you have to be ready to deal with it.

 

 

Dave

[1-3-2-4]

lol I like how they cover up the wrx come on now.. don't they know most people know whats under all that?

[nipper]

Had our first small snow fall and freeze. Had my first almost slide thru a traffic light when the ABS kicked in. Was only going about 10 MPH when I hit a patch of slush that would have been a non-event without ABS. Love the car (97 Legacy) hate it's ABS.

 

I had the chance to do some rough tests in a parking lot with the last blizzard. (I found if you pop the car in neutral whne the ABS kicks in (I am assuming safe distance and of course no one is overdirivng for the weather conditions) the ABS works much better. The ABS could have used another sensor or two or a software tweak.

 

The ABS and AWD in automatics fight each other, along with the mass of the car at lower speeds. I now have much better confidence in the ABS.

[Setright]

Now, I have to admit, that I don't like all the false confidence that all these electronic gadgets instill.

 

No doubt, ABS can and will cause some people to take more chances.

 

I find this effect is increased VASTLY with the influx of ESP. Joe-Smoe now thinks his "modern" ESP equipped car is incapible of having an accident. THIS IS A DANGEROUS EFFECT.

 

ESP can, in some cases rescue Joe when he makes a big mistake with his inputs in a tricky situation, but it cannot allow him to take corners above the speeds dictated by physics.

 

 

 

 

HOWEVER, having said that, there is one important thing to mention about ABS. The difference between static and dynamic friction.

 

Once two objects have "released" eachother and allow slip, the grip available is reduced. Depending on surfaces, anywhere between 10 and 25%. Therefore, the locked wheels that some people are favouring here, have LESS GRIP. Yes, they do. (Of course, studs on ice don't count)

 

The reason ABS, especially early types can lose out in theoretical optimal braking distance is the pulsing. The brakes have to be released a bit to get the wheels moving again. The shorter pulses of newer systems allow much better stopping distances.

 

 

Dynamic vs. static friction. Grab a book, place a small object on it, like a die. Tilt the book slowly to one side. Once the die starts to slide, tilt the book back toward horizontal...but only slightly. You will find that the die will STILL KEEP SLIDING, since it is only held by dynamic friction. It will now keep moving where it would have stood still had it not released the book already.

[hankosolder2]

Setright-

 

I don't think that anyone is arguing that ABS is a detriment to stopping in dry conditions, which is where your static coefficient of friction vs. dynamic really comes into play.

 

I think (and I may be wrong about this) that the spread between static and dynamic friction for icy and snowy surfaces is much smaller than it is in dry conditions. Add other factors, such as the ability of a locked up tire to create a helpful-to-stopping "snow wedge" and the advantage of ABS becomes a disadvantage.

[naru]

Now, I have to admit, that I don't like all the false confidence that all these electronic gadgets instill.

 

No doubt, ABS can and will cause some people to take more chances.

 

 

No doubt at all.

Read somewhere that ABS equipped cars are 200% as likely as non-ABS cars to be involved in a roll over accident.

[StructEngineer]

I think (and I may be wrong about this) that the spread between static and dynamic friction for icy and snowy surfaces is much smaller than it is in dry conditions. Add other factors, such as the ability of a locked up tire to create a helpful-to-stopping "snow wedge" and the advantage of ABS becomes a disadvantage.

 

x2

 

I also think there's other mechanisms going on such as the snow wedge, and the propensity for the tire to dig down into the snow instead of rolling over it. The "static friction" when the tire is rolling over snow is directly influenced by the shearing strength of the snow layer beneath the tire. It could very well cause an effective static friction coefficient that is less than the dynamic coefficient of the tire sliding along a thinner snow layer (or even making contact with the pavement.

 

In other words, it's not as cut and dry as the example of a die sliding on a book. Speaking as someone who's taken several physics courses.

[rverdoold]

My impreza does not have ABS (nor airbags) and since years we have a very big winter in Holland. The government ran out of salt for de-icing the road a couple of times. We need salt over-here because the surface we drive on is designed for lots of rain (open structure concrete asphalt of 5 cm). So if it rains the water runs through the pores of the road and does not splash it is kind of dry. However the snow of last weeks puts a layer of ice in the pores resulting in the top layer of asphalt braking off. Last week i broke my windscreen because of some stones flying around, luckily i have insurance for windows not for paint. So no salt no de-icing of the asphalt leaving an ice layer.

Still (mainly BMW and Audi) drivers race like mad on frozen shiny roads. You learn driving without ABS. I have been driving in winters in Latvia on iced roads just taking care. Still i like winters and snow just take care and have the proper tyres seems more important to me than ABS.

 

Over here ABS and ESP made many people drive very very careless.

Edited February 13, 2010 by rverdoold
typo

[Setright]

Rver..same conditions here in Denmark.

 

I was in Sweden - for work- on Friday. They don't bother so much with all the salt. Most main roads are just treated with a layer of sand/fine gravel and this gives quite remarkable grip.

 

I will still maintain that with the Conti TS810 (205/55R16) that my 1999 Impreza is wearing, my braking distance is shorter with ABS activated.

 

The trick is to trust it, and mash the pedal. If you let off the pressure, you'll coast too far.

[rverdoold]

Rver..same conditions here in Denmark.

 

I was in Sweden - for work- on Friday. They don't bother so much with all the salt. Most main roads are just treated with a layer of sand/fine gravel and this gives quite remarkable grip.

 

The trick is to trust it, and mash the pedal. If you let off the pressure, you'll coast too far.

 

Same as in Latvia they just have the sand gravel. And many roads there are dirt/gravel roads with tilted corners so as long as you take them on the inside (hoping no other car comes from the other side) it is fine.

Without ABS i just floor the brake pedal until i have to correct steering and this seems to work fine.

[CNY_Dave]

x2

 

I also think there's other mechanisms going on such as the snow wedge, and the propensity for the tire to dig down into the snow instead of rolling over it. The "static friction" when the tire is rolling over snow is directly influenced by the shearing strength of the snow layer beneath the tire. It could very well cause an effective static friction coefficient that is less than the dynamic coefficient of the tire sliding along a thinner snow layer (or even making contact with the pavement.

 

In other words, it's not as cut and dry as the example of a die sliding on a book. Speaking as someone who's taken several physics courses.

 

This is the case for me- not that much snow, lock the tires, tires dig through to pavement, car stops.

 

 

 

Dave