mdtobe

I'm not a spokesperson for ABS - I'm just studying Emergency Medicine and I am acutely aware of the carnage caused by car accidents. And I am used to forming my opinions from reading peer-reviewed journals and legitimate research - something that apparently some people around here don't believe in.

And it's not a waste of time talking to me - unless you are dogmatic in your opinions and one or more of them happens to vary from mine.

The point raised about lifted vehicles vs lower sports-oriented cars is an interesting one. I have to concede, it is possible that one could steer so hard as to tip the vehicle over - and under certain circumstances an ABS system could make that more likely (ironically by affording the driver lateral control he or she otherwise wouldn't have). But I think in the big picture, it is better to be able to steer through a emergency stop (one potentially happening on water or snow, mitigating the lateral acceleration generated anyway, preventing the tip over possibility), then to give up that ability.

And yes, some drivers can nearly duplicate the ability of an ABS system under some conditions. I like to think I am one of those drivers. But "nearly" is not a tie score. And what one can do under test conditions when mentally prepared to do it is different from what one can do when startled and reacting in a potentially life threatening situation.

Sorry if I ruffled a few feathers here. Stay safe.

Cheers,

John

P.S. I also have my own anecdotal evidence. My wife was driving our non-ABS Miata on the freeway when an unexpected ice storm came up. Traffic was heavy and only moving about 20 mph. All of a sudden, just as they were upon an ice patch the cars in front of her all hit the brakes and jammed to a stop. The car in front of hers had ABS. Hers didn't. She didn't get hurt, but the $3000+ repair bill still hurts! And before anyone goes for the woman driver jokes (which I love), she's German, and as such was trained to drive in Germany where the amount of training is similar to getting a Sport Pilot license here. She's got years of Northern Germany Autobahn experience, and if anybody could have stopped that car, she could have.

mdtobe

Yes, the old "pumping the brakes" idea had more to do with preventing heat build up (back when cars tended to have drum brakes front and rear). Nothing like 300+hp powering 4000+ pounds of full size '60's sedans with front and rear drum brakes on skinny little bias-ply tires down the street!

Time for a Physics Lesson! (Cue the yawn from many).

A full explanation of threshold braking:

There are two types of friction forces: Static Friction and Dynamic Friction. For any surface (or surfaces), there is the coefficient of static friction and the coefficient of dynamic (moving) friction. The coefficient of static friction is always stronger for any given surface than its coefficient of dynamic friction.

Example: There is a heavy box on the floor. To get it moving you have to push harder on it than you do once it's moving to keep it moving. That's because while it is staying still, it's the static friction force working against your push that you have to overcome. Once you get it moving, it is then just its dynamic friction force (the weaker one) working against you.

But what does this have to do with braking?!?! I'll explain (if you're still awake).

When a tire is rolling on street, while it is moving down the street, at the point where the tire is in contact with the street the tire is NOT moving relative to the street! Doesn't that sound weird? But it is true. The exact spot on the tire that is touching the street at that exact instant is not moving relative to the street. It's just that as the tire rolls, new spots on that tire touch new spots on the street. So, since the tire is not moving relative to the street, it is the static force of friction acting on the tire from the street and this is the stronger of the two types of friction forces.

But if the tire begins to skid, one spot on that tire now is moving down the street, and therefore, it is now the dynamic force of friction (the weaker of the two) which now acts upon the tire. That is why a skidding tire takes longer to stop than a tire that is still rolling with the brakes applied at the "threshold" of a skid. And once a skid happens (and the tires stop revolving) all steering power from the tire (if it is a front tire) is also negated and all lateral stability (if it is a rear tire) is also negated.

That's it. Interesting (at least to me) Physics lesson is over.

Now I have a question for the serious off-roaders out there (though I successfully forded a river in Montana once in my Ford Bronco, to the delight of my then new girlfriend, I am by no means very knowledgeable about serious off roading - I was just damn lucky that time):

What is it about ABS that hinders off-roading? I think I remember it having something to do with rock crawling, but I'm not sure.

Cheers,

John

Orlo

Every once in a while, the ABS debate comes up on here. It's more divisive than the abortion issue.

You have those who have some old school leanings that think abs is a useless system favored by politicians and poor drivers.

Then you have ppl who understand that a well engineered abs system with good tires can help the average and below average driver stay out of trouble.

Since the roads are filled with marginal drivers, I will advocate for abs just so I have a fighting chance against the masses.

BlueRidgeMark

And then you have people who understand that a skilled driver can do better than ABS.

But yes, let's have ABS for the masses, for the reasons stated!

Jeep Driver

I'm certain you are aware?- http://fortune.com/2016/07/08/harley...investigation/
And the 2 year interval is pure BS.


Engineers? Engineered? Engineering? and the NHTSA? EPA?

I'm also certain you are aware of this?- https://www.theguardian.com/technolo...-car-elon-musk


Also, look up how may people have died as a result of CAFE standards since the '70s........I won't bother............


I'm not 'old school', I think for myself.
The last thing I need is for some 28 year old dip**** graduate student who has never done a damn thing in his/her life to tell me what is safe for me and mine. Keep your white coats and your stupidity to yourself, thank you.


I'll keep control of my vehicle, without your help.




EDIT to add-

My comments are not directed at anyone on this forum........speaking in general terms.

mdtobe

Might not be able to lock up on dry pavement. But on wet pavement, snow or ice, certainly can and would.

mdtobe

Regarding the idea that a good driver can outperform ABS, I did find one statement from a 1990 Popular Mechanics article claiming that a "trained test driver can outperform ABS with subtle movement of the brake pedal". I can find nothing of substance written in the past quarter century that substantiates that claim. I've raced cars and motorcycles. While playing trumpet for a circus in the late '80's I spent two nine month tours driving one of the show's semis. I've got 38 years of driving experience on everything from race tracks to the Autobahn. I searched for a while to find a Jeep Cherokee with the ABS option and I'm glad I did. But to each his own.

Jeepin'_Aint_EZ

I don't believe we needed the physics lesson but thanks anyway lol. I can appreciate a good back-and-forth so-to-speak but ABS isn't the cure-all for braking.

It's a standard now because people are lazy, who resist change or learning new things, and most of all, terrible drivers. I'm referring to the masses. Not the small percentage of enthusiasts or people who take driving a little more serious than grocery shopping. Now we have TPMS sensors standard because people aren't smart enough to check their air pressures from time to time. We have back-up camera's and full perimeter cameras. ESC paired with ABS now. Most cars don't even come with a spare tire anymore, probably because no one knows how to change a flat anymore! COME ON! I mean, the majority of people don't know what the lights on their dashboard mean! How about we have better driving programs that teach sheeple how to properly operate a vehicle?

Anyone who's driven in snow knows that ABS is the enemy. It's not going to do much on ice either unless you have studded tires. As far as off-road performance, why would you want your brakes to do something you don't want them to? If I smash the brake pedal, I expect the tires to stop, or at least react properly to the amount of pressure I'm applying so ME, THE DRIVER, can manipulate the vehicle. If ABS takes over, you can be forced into a position you don't want to be in. I can't think of one situation where you would want ABS while wheelin. Soft sand is essentially the same as snow driving. You WANT the snow/sand to pack up in front of a stopped tire. I'm glad my rig didn't come with ABS. I would have pulled that crap out. My 400hp srt-4 didn't come equipped with ABS and that was a fwd monster to drive. I was in some hairy situations and never needed ABS.

People are becoming more and more detached from the modern vehicle. It's a sad thing really. But I digress.

mdtobe

Hey there,

I TOTALLY agree with what you wrote about the dumbing of the masses and how technology is catering to that phenomena. And I agree that in off-road situations ABS can be a problem. And having lived in Germany (where drivers spend thousands of dollars and as much time properly learning to drive as a Sport Pilot licensee spends getting his pilot license), I TOTALLY agree about the lack of proper driver education in this country. But having had years and years of experience driving on snow and ice (usually with good, but non-studded winter tires), I cannot see how you could possibly think that ABS is a hindrance on snowy or icy roads. Deep snow off road - maybe.

I've got nearly 40 years of driving experience. Everything from motorcycles to semi tractor trailers (in the mountains, in the winter). I've actively raced, and while I might not be the best driver, I'm definitely up there in the percentiles. Yet I probably would not be here writing this had my BMW not had ABS on one particular day. You might have convinced yourself that ABS is a terrible thing. You're not going to convince me (or for that matter, the vast majority of people).

Cheers,

John

ChrisCrash

So I just picked up a C8.25 to replace my D35C and I was wondering what to do myself. Consensus here seems to be to remove all the ABS components and either leave the system as is or upgrade to new pads and rotors. Would changing the rear from drum to disc be in best interest as well?

JamromXJ

I did the same on my rig, but it's still drum in the rear. All I did was cut out the ABS cables. You're not going to need them anymore... oh... and remove the ABS light bulb from the dash... it will remain on forever.

Other than that, it's bolt off, bolt on... happier days with the C8.25
.
Good luck