The dos and don'ts of anti-lock brakes - Autos.ca

Abs is NOT always better.

And I read in the "other" thread that you stop faster once the tires are locked up. THAT is not true. you have less traction once your tires are locked. The problem is the abs system gets fooled.

 

I personally hate anti lock brakes for most of those reasons. I will agree with what they wrote. I'll also agree to the skidding on loose surfaces, it will slow the car better than ABS cars. ABS wants the tire to keep rolling, a nonabs car will let you apply the brakes hard enough to stop the wheel. Low speeds in snow that comes into play, you can get a wedge built up and actually stop where abs you can't, down side is you lose steering control while sliding. In the hands of a good driver an abs car will stop faster just about everytime. The thing that makes abs useful is that its safer buy helping keep steering contol while braking usually at the expense of stopping distance.

 

The observations in that article coincide with the observations i've made driving vehicles with ABS.

in particular, rough roads, and ice.

while somewhat counterintuitive, the most effective way to stop on ice is to repeatedly lock and unlock the wheels. most of your stopping is done when you let off the brakes and the wheels have to spin back up. By locking and unlocking repeatedly, you are maximizing the use of the traction use of the static friction between the tire and the ice, and by unlocking you are maximizing the use of the kentic friction between the tire and the ice.

when unlocking, rather than simply sliding along the ice, the friction is being used to spin the wheels back up to speed. The energy required to spin the wheels back up slows the car, and IMO, is more than the energy it takes to stop the wheel with the brakes.

ABS will always try to find that fine line of brake action to keep the wheels from locking - which increases stability, but it is not the most effective way to stop when the friction is near zero (ice). with ABS, the wheels will still lock occasionally, but it does not lock and unlock the wheels in a pattern that is conducive to stopping on ice.

The other time that ABS can hinder stopping is when you loose braking traction at one wheel. if your front right is in the sand, and your front left is on dry pavement, ABS will typically extend stopping distances. ABS will try to keep the wheel in the sand from locking, but in doing so it will reduce the braking action to the wheel with traction to keep the vehicle stable. It would be more effective to transfer the "excess" brake action from the wheel without traction, to the wheel with traction, but there is no way that the computer can know what type of surface you are driving on at any given instant. it just knows to keep the wheels from locking.

They aren't perfect for every road surface, but they are effective at keeping the vehicle stable and controllable in emergency manuvers.

My only real angst with ABS is that when you do encounter road surfaces in which the ABS system hinders stopping performance, you only option is to mash the pedal, hold on tight, steer around it, and hope for the best. Where a really attentive driver knows WHY his wheel locked, and what to do to get the vehicle to stop effectively. My angst comes from the frequency in which i encounter these types of driving conditions. snowpacked and washboarded gravel roads are part of my life, and if you were overdriving, the ABS can really make you pucker. the solution is to slow down earlier so as not to push the limits of traction, KNOWING that the ABS is going to do what it does.

but, alas, most drivers are not that attentive.

they have made it better, though (IMO), by reducing the ABS efforts at very low vehicle speeds. once you get below a few MPH, the ABS seems to not do very much (in my vehicles, anyway), and it gives the driver back some control. This works well, because even if you don't know how to get your vehicle to stop, you are at least going slow enough to where the severity of a crash is minimized.

Just my thoughts.
which, apparently (as seen in the other thread), aren't worth a hill of beans

 

I despise traction control and ABS! Takes control away from me. I grew up learning how to defensibly drive before any of this "stuff" was mandatory. Wish I could yank both systems out by the roots and toss. These systems are designed more for the cerebrally challenged and beginner drivers. And to cover the lawyers & Big Brother. IMO I see very little safety improvement. More times than not both systems counter-intuitively took away control when I was in control. I never rant with out at least adding something good.
One suggestion is if your like me.... just keep it in 4WD to deactivate the traction control. When I get into a sticky(slippery) situation I can give it some gas and pull away from trouble,or reverse if you absolutely cant stop in a panic situation. That happened to me on an icy hill coming into a 4 way stop. Id rather have 4 wheels going backwards then abs and TC taking control away. If I had not been in reverse in 4WD I would have slid through that 4 way into a school bus. I was going about 2mph. Of course the best defense is you need to be a sane driver and use speed that's sensible for the conditions, unless your off road. Be nice if there was an off-road **** for snow and mud fun but you know that **** would be abused and always on.

 

i agree to some point.

with the caveot that in the big picture they do more good than harm. in all but a few instances, ABS will outperform a human driver. Also, it gives control to those who would otherwise have none.

also, when combined with stability control, ABS can do things that human drivers cannot. e.g. hit the front left brake only to force the car to rotate out of a spin.

a good driver can get himself out of a spin, but stability control and ABS can do it more effectively because it has abilities that drivers do not.

if there was an easy fix for the instances and situations i've outlined above, i'd be completely in love with it, but for those shortcomings - and the frequency in which i encounter them - i do have some reservations about the lack of control at times.

 

I was playing with this last night on the way home on snow covered roads. I thought it was really cool how the car applied the brakes whenever I forced an understeer to bring the car around.

I really like stability control and ABS, as they are a benefit in the overwhelming majority of circumstances.

 

The bottom line is that ABS will not create traction. It works with the traction it has to stop you. A decent driver can usually stop faster. These " through the intersection" incidents just indicate to me that the driver of the vehicle was going too fast for conditions.

 

I have to agree ABS should be an option with an on/off switch. I could not get my truck to stop fast enough with ABS and when it did stop I was questioned as to why there was on skid marks, Duh to the cop.

 

They must have spent millions on ABS research and millions more installing it so to those who think it is a bad idea; You're wrong.

 

So you were spinning your wheels in reverse sliding down a hill?

 

I as well hate ABS, traction control, and whatnots.

 

Often clicking the parking brake enough to activate the dash lite will disable abs and traction control.
If you really really wanted to, you could hook up a switch to the parking brake switch circuit to turn it on when you wanted to disable the safety features.

Imo, 99.5% of the time a seatbelt is safer. But, flip the car over into a water filled ditch and you found the other .5%.
Hiway patrol officer once told me, he's never had to unbuckle a dead body.

Sent from my Sprint PC36100 using IB AutoGroup

 

I just HATE the feeling the brake petal has when ABS kicks in. Scares the crap outta me...The only time i have felt it was trying to stop a heavy trailer on a wet road when some moron pulls right out in front of me or turns off at the last second with no blinker.

 

I drove a towtruck for 16 years. In my experience, there's NEVER a good time to lock up the wheels, NEVER! You can theorise all you want to, I've been there, and cleaned up the carnage. I've been in more nasty situations driving than many have even read about.

 

I'd also disagree with the idea that locking the wheels will stop you faster. One of the constants that I remember was that the coefficient of friction is ALWAYS greater static than sliding.