ABS question, mechanically oriented.
#11
Guest
Posts: n/a
Re: ABS question, mechanically oriented.
On Fri, 12 Dec 2003 01:15:22 -0000, "Hairy One Kenobi"
<abuse@[127.0.0.1]> wrote:
>Theoretically, depending upon the materials used, it could shorten the life
>of the calliper seals.
I politely disagree.
The actual travel of the calipers when the ABS opens and re-applies
brake pressure is IMO a few hundreds of a Millimeter. The pressure on
the pad's fluctuates, but for that not a lot of travel is needed
anyway. This travel is IMO covered in the flexibility of the seals
itself, there's not much real relative movement there. If you look at
it the travel of the calipers is mostly caused by the wear of the
pads, making them thinner and the calipers moving out.
I think the ABS control valve and the tubes running to the wheels will
vibrate but I haven't heard or read about mechanical damages to these
systems.
Regards
Wolfgang
--
* Audi A6 Avant TDI *
* reply to wolfgang dot pawlinetz at chello dot at *
<abuse@[127.0.0.1]> wrote:
>Theoretically, depending upon the materials used, it could shorten the life
>of the calliper seals.
I politely disagree.
The actual travel of the calipers when the ABS opens and re-applies
brake pressure is IMO a few hundreds of a Millimeter. The pressure on
the pad's fluctuates, but for that not a lot of travel is needed
anyway. This travel is IMO covered in the flexibility of the seals
itself, there's not much real relative movement there. If you look at
it the travel of the calipers is mostly caused by the wear of the
pads, making them thinner and the calipers moving out.
I think the ABS control valve and the tubes running to the wheels will
vibrate but I haven't heard or read about mechanical damages to these
systems.
Regards
Wolfgang
--
* Audi A6 Avant TDI *
* reply to wolfgang dot pawlinetz at chello dot at *
#12
Guest
Posts: n/a
Re: ABS question, mechanically oriented.
"Wolfgang Pawlinetz" <me@privacy.net> wrote in message
news:960jtvsqkrg5rtr6nmpod28tupggl38c07@4ax.com...
> On Fri, 12 Dec 2003 01:15:22 -0000, "Hairy One Kenobi"
> <abuse@[127.0.0.1]> wrote:
>
> >Theoretically, depending upon the materials used, it could shorten the
life
> >of the calliper seals.
>
> I politely disagree.
>
> The actual travel of the calipers when the ABS opens and re-applies
> brake pressure is IMO a few hundreds of a Millimeter. The pressure on
> the pad's fluctuates, but for that not a lot of travel is needed
> anyway. This travel is IMO covered in the flexibility of the seals
> itself, there's not much real relative movement there. If you look at
> it the travel of the calipers is mostly caused by the wear of the
> pads, making them thinner and the calipers moving out.
>
> I think the ABS control valve and the tubes running to the wheels will
> vibrate but I haven't heard or read about mechanical damages to these
> systems.
I'm thinking crack propagation. That said, I would reverently hope that the
callipers had been overhauled w-a-y before then..
The pipes should be OK, as long as they're not copper (work hardening)
H1K
news:960jtvsqkrg5rtr6nmpod28tupggl38c07@4ax.com...
> On Fri, 12 Dec 2003 01:15:22 -0000, "Hairy One Kenobi"
> <abuse@[127.0.0.1]> wrote:
>
> >Theoretically, depending upon the materials used, it could shorten the
life
> >of the calliper seals.
>
> I politely disagree.
>
> The actual travel of the calipers when the ABS opens and re-applies
> brake pressure is IMO a few hundreds of a Millimeter. The pressure on
> the pad's fluctuates, but for that not a lot of travel is needed
> anyway. This travel is IMO covered in the flexibility of the seals
> itself, there's not much real relative movement there. If you look at
> it the travel of the calipers is mostly caused by the wear of the
> pads, making them thinner and the calipers moving out.
>
> I think the ABS control valve and the tubes running to the wheels will
> vibrate but I haven't heard or read about mechanical damages to these
> systems.
I'm thinking crack propagation. That said, I would reverently hope that the
callipers had been overhauled w-a-y before then..
The pipes should be OK, as long as they're not copper (work hardening)
H1K
#13
Guest
Posts: n/a
Re: ABS question, mechanically oriented.
In article <aW5Cb.255$u52.45264@zonnet-reader-1>, R@L <reply@usent.com>
writes
>It's not aproaching lock-up, it's lock-up! That's what you hear on a dry
>road and you'll even leave marks on the road which the cops use to determine
>your initial speed.
Although when the wheels actually lock-up, they obviously have to slow
down to zero rotational speed, I believe this slow down happens so
quickly that not even the fastest ABS system is actually capable of
detecting the rapid speed drop and releasing the calipers in time to
stop it. Basically by the time the calipers are released, the wheel has
already stopped rotating. Obviously the faster the system reacts, the
less time the wheels will spend "stopped", but no system can stop it
completely.
--
Toby
writes
>It's not aproaching lock-up, it's lock-up! That's what you hear on a dry
>road and you'll even leave marks on the road which the cops use to determine
>your initial speed.
Although when the wheels actually lock-up, they obviously have to slow
down to zero rotational speed, I believe this slow down happens so
quickly that not even the fastest ABS system is actually capable of
detecting the rapid speed drop and releasing the calipers in time to
stop it. Basically by the time the calipers are released, the wheel has
already stopped rotating. Obviously the faster the system reacts, the
less time the wheels will spend "stopped", but no system can stop it
completely.
--
Toby
#14
Guest
Posts: n/a
Re: ABS question, mechanically oriented.
In article <BBFE3304.4D2C%ccleaveland@earthlink.nospam.net> , Grover
<ccleaveland@earthlink.nospam.net> writes
>Ok, this is sort of funny now.
>
>I have known (through inattentive driving and such) what ABS feels like for
>years now. It's also caused me to have no illusions of my personally being
>able to out perform it - especially while steering. I most likely can not
>without the proper training, practice, and road conditions.
I don't believe *any* human being is capable of out-performing a decent
ABS system.
>After yesterday's event, I am just now wondering (new thread) what the weak
>point in the mechanical system might be, regarding wear.
>
>In other words, if I want to practice max stopping/steering maneuvers within
>slick or snowy parking lots, am I wearing anything out aside from my brake
>pads and rotors?
>
>The answer seems to be "no", but it was worth asking.
The one obvious wear issue is the tyres themselves (tires for our US
cousins I doubt a full bore ABS assisted stop from high speed does
much good to your tyres at all, but then this is relative. Compared to
a long skid on totally locked wheels, the tyre wear is obviously less
and distributed around the circumference of the tyre rather than in a
single spot, but there's obviously more wear involved than if ABS were
never invoked in the first place.
--
Toby
<ccleaveland@earthlink.nospam.net> writes
>Ok, this is sort of funny now.
>
>I have known (through inattentive driving and such) what ABS feels like for
>years now. It's also caused me to have no illusions of my personally being
>able to out perform it - especially while steering. I most likely can not
>without the proper training, practice, and road conditions.
I don't believe *any* human being is capable of out-performing a decent
ABS system.
>After yesterday's event, I am just now wondering (new thread) what the weak
>point in the mechanical system might be, regarding wear.
>
>In other words, if I want to practice max stopping/steering maneuvers within
>slick or snowy parking lots, am I wearing anything out aside from my brake
>pads and rotors?
>
>The answer seems to be "no", but it was worth asking.
The one obvious wear issue is the tyres themselves (tires for our US
cousins I doubt a full bore ABS assisted stop from high speed does
much good to your tyres at all, but then this is relative. Compared to
a long skid on totally locked wheels, the tyre wear is obviously less
and distributed around the circumference of the tyre rather than in a
single spot, but there's obviously more wear involved than if ABS were
never invoked in the first place.
--
Toby
#15
Guest
Posts: n/a
Re: ABS question, mechanically oriented.
"Toby Groves" <news@iconia.org.uk> wrote in message
news:3DxuZiAXbG3$Ew7e@iconia.org.uk...
> In article <BBFE3304.4D2C%ccleaveland@earthlink.nospam.net> , Grover
> <ccleaveland@earthlink.nospam.net> writes
> >Ok, this is sort of funny now.
> >
> >I have known (through inattentive driving and such) what ABS feels like
for
> >years now. It's also caused me to have no illusions of my personally
being
> >able to out perform it - especially while steering. I most likely can
not
> >without the proper training, practice, and road conditions.
>
> I don't believe *any* human being is capable of out-performing a decent
> ABS system.
Then I believe that you should re-read the comments, take any additional
training that (may) be required, and prove yourself wrong.
> >After yesterday's event, I am just now wondering (new thread) what the
weak
> >point in the mechanical system might be, regarding wear.
> >
> >In other words, if I want to practice max stopping/steering maneuvers
within
> >slick or snowy parking lots, am I wearing anything out aside from my
brake
> >pads and rotors?
> >
> >The answer seems to be "no", but it was worth asking.
>
> The one obvious wear issue is the tyres themselves (tires for our US
> cousins I doubt a full bore ABS assisted stop from high speed does
> much good to your tyres at all, but then this is relative. Compared to
> a long skid on totally locked wheels, the tyre wear is obviously less
> and distributed around the circumference of the tyre rather than in a
> single spot, but there's obviously more wear involved than if ABS were
> never invoked in the first place.
Tyre wear should be fairly neutral, I'd have thought. Locking the wheels
would induce more wear (the phrase "flat-spot" ring a bell? ;o)
The number of flat-spots that an ABS system would induce is - IMHO - a very
minor amount of wear in the overall wear-pattern of a tyre, assuming
"normal" usage and material. I think that we agree on that one! )
H1K
news:3DxuZiAXbG3$Ew7e@iconia.org.uk...
> In article <BBFE3304.4D2C%ccleaveland@earthlink.nospam.net> , Grover
> <ccleaveland@earthlink.nospam.net> writes
> >Ok, this is sort of funny now.
> >
> >I have known (through inattentive driving and such) what ABS feels like
for
> >years now. It's also caused me to have no illusions of my personally
being
> >able to out perform it - especially while steering. I most likely can
not
> >without the proper training, practice, and road conditions.
>
> I don't believe *any* human being is capable of out-performing a decent
> ABS system.
Then I believe that you should re-read the comments, take any additional
training that (may) be required, and prove yourself wrong.
> >After yesterday's event, I am just now wondering (new thread) what the
weak
> >point in the mechanical system might be, regarding wear.
> >
> >In other words, if I want to practice max stopping/steering maneuvers
within
> >slick or snowy parking lots, am I wearing anything out aside from my
brake
> >pads and rotors?
> >
> >The answer seems to be "no", but it was worth asking.
>
> The one obvious wear issue is the tyres themselves (tires for our US
> cousins I doubt a full bore ABS assisted stop from high speed does
> much good to your tyres at all, but then this is relative. Compared to
> a long skid on totally locked wheels, the tyre wear is obviously less
> and distributed around the circumference of the tyre rather than in a
> single spot, but there's obviously more wear involved than if ABS were
> never invoked in the first place.
Tyre wear should be fairly neutral, I'd have thought. Locking the wheels
would induce more wear (the phrase "flat-spot" ring a bell? ;o)
The number of flat-spots that an ABS system would induce is - IMHO - a very
minor amount of wear in the overall wear-pattern of a tyre, assuming
"normal" usage and material. I think that we agree on that one! )
H1K
#16
Guest
Posts: n/a
Re: ABS question, mechanically oriented.
Hairy One writes:
>"Toby Groves" <news@iconia.org.uk> wrote in message
>news:3DxuZiAXbG3$Ew7e@iconia.org.uk...
>> In article <BBFE3304.4D2C%ccleaveland@earthlink.nospam.net> , Grover
>> <ccleaveland@earthlink.nospam.net> writes
>> >Ok, this is sort of funny now.
>> >
>> >I have known (through inattentive driving and such) what ABS feels like
>for
>> >years now. It's also caused me to have no illusions of my personally
>being
>> >able to out perform it - especially while steering. I most likely can
>not
>> >without the proper training, practice, and road conditions.
>>
>> I don't believe *any* human being is capable of out-performing a decent
>> ABS system.
>
>Then I believe that you should re-read the comments, take any additional
>training that (may) be required, and prove yourself wrong.
Yeah, what he says. I know lots of drivers that can beat abs. It is nothing
more than training. At a school teaching teens defensive driving in Vermont,
after a lane change exercise using abs, we turned off the abs and did it the
old way with threshold braking. My first student did it perfectly at 45 mph.
I upped the speed to 55 and again he did it as well as anyone I've ever
observed using threshold braking. This kid was 18 and he was good. We
normally didn't go above 55 without abs, but he was so good I took him through
at 60. Again, perfect.
We questioned him later and found out that he lived on a farm and drove the
school bus. His farm was on a hill and at the bottom was a stopsign: you had
to turn left or right or go into a river. He taught himself threshold braking
on that hill in the worst of weather.
Dave
http://hometown.aol.com/davplac/myhomepage/index.html
>"Toby Groves" <news@iconia.org.uk> wrote in message
>news:3DxuZiAXbG3$Ew7e@iconia.org.uk...
>> In article <BBFE3304.4D2C%ccleaveland@earthlink.nospam.net> , Grover
>> <ccleaveland@earthlink.nospam.net> writes
>> >Ok, this is sort of funny now.
>> >
>> >I have known (through inattentive driving and such) what ABS feels like
>for
>> >years now. It's also caused me to have no illusions of my personally
>being
>> >able to out perform it - especially while steering. I most likely can
>not
>> >without the proper training, practice, and road conditions.
>>
>> I don't believe *any* human being is capable of out-performing a decent
>> ABS system.
>
>Then I believe that you should re-read the comments, take any additional
>training that (may) be required, and prove yourself wrong.
Yeah, what he says. I know lots of drivers that can beat abs. It is nothing
more than training. At a school teaching teens defensive driving in Vermont,
after a lane change exercise using abs, we turned off the abs and did it the
old way with threshold braking. My first student did it perfectly at 45 mph.
I upped the speed to 55 and again he did it as well as anyone I've ever
observed using threshold braking. This kid was 18 and he was good. We
normally didn't go above 55 without abs, but he was so good I took him through
at 60. Again, perfect.
We questioned him later and found out that he lived on a farm and drove the
school bus. His farm was on a hill and at the bottom was a stopsign: you had
to turn left or right or go into a river. He taught himself threshold braking
on that hill in the worst of weather.
Dave
http://hometown.aol.com/davplac/myhomepage/index.html
#17
Guest
Posts: n/a
Re: ABS question, mechanically oriented.
"Toby Groves" <news@iconia.org.uk> wrote in message news:<5jSthWAZYG3$EwZR@iconia.org.uk>...
> In article <aW5Cb.255$u52.45264@zonnet-reader-1>, R@L <reply@usent.com>
> writes
> >It's not aproaching lock-up, it's lock-up! That's what you hear on a dry
> >road and you'll even leave marks on the road which the cops use to determine
> >your initial speed.
>
> Although when the wheels actually lock-up, they obviously have to slow
> down to zero rotational speed, I believe this slow down happens so
> quickly that not even the fastest ABS system is actually capable of
> detecting the rapid speed drop and releasing the calipers in time to
> stop it. Basically by the time the calipers are released, the wheel has
> already stopped rotating. Obviously the faster the system reacts, the
> less time the wheels will spend "stopped", but no system can stop it
> completely.
Actually, I think you're incorrect. I know that the engineers decide
*how much* rotational difference is tolerated before the ABS is
engaged. BMW used "25%", last time I'd heard anything in particular.
Now what *that* means I'm not quite sure. We didn't ask for enough of
an explanation to completely understand it. Any *more* retentive
engineer/trivia freaks out there?
--
C.R. Krieger
(Been there; done that)
> In article <aW5Cb.255$u52.45264@zonnet-reader-1>, R@L <reply@usent.com>
> writes
> >It's not aproaching lock-up, it's lock-up! That's what you hear on a dry
> >road and you'll even leave marks on the road which the cops use to determine
> >your initial speed.
>
> Although when the wheels actually lock-up, they obviously have to slow
> down to zero rotational speed, I believe this slow down happens so
> quickly that not even the fastest ABS system is actually capable of
> detecting the rapid speed drop and releasing the calipers in time to
> stop it. Basically by the time the calipers are released, the wheel has
> already stopped rotating. Obviously the faster the system reacts, the
> less time the wheels will spend "stopped", but no system can stop it
> completely.
Actually, I think you're incorrect. I know that the engineers decide
*how much* rotational difference is tolerated before the ABS is
engaged. BMW used "25%", last time I'd heard anything in particular.
Now what *that* means I'm not quite sure. We didn't ask for enough of
an explanation to completely understand it. Any *more* retentive
engineer/trivia freaks out there?
--
C.R. Krieger
(Been there; done that)
#18
Guest
Posts: n/a
Re: ABS question, mechanically oriented.
In my opinion triggering the ABS once in a while can't do much harm but
rather help "moving up" rear calipers which tend to hang and cause excessive
wear/increased fuel consumption.
Rune
"Hairy One Kenobi" <abuse@[127.0.0.1]> wrote in message
newsvhCb.1625$FN.954@newsfep4-winn.server.ntli.net...
> "Wolfgang Pawlinetz" <me@privacy.net> wrote in message
> news:960jtvsqkrg5rtr6nmpod28tupggl38c07@4ax.com...
> > On Fri, 12 Dec 2003 01:15:22 -0000, "Hairy One Kenobi"
> > <abuse@[127.0.0.1]> wrote:
> >
> > >Theoretically, depending upon the materials used, it could shorten the
> life
> > >of the calliper seals.
> >
> > I politely disagree.
> >
> > The actual travel of the calipers when the ABS opens and re-applies
> > brake pressure is IMO a few hundreds of a Millimeter. The pressure on
> > the pad's fluctuates, but for that not a lot of travel is needed
> > anyway. This travel is IMO covered in the flexibility of the seals
> > itself, there's not much real relative movement there. If you look at
> > it the travel of the calipers is mostly caused by the wear of the
> > pads, making them thinner and the calipers moving out.
> >
> > I think the ABS control valve and the tubes running to the wheels will
> > vibrate but I haven't heard or read about mechanical damages to these
> > systems.
>
> I'm thinking crack propagation. That said, I would reverently hope that
the
> callipers had been overhauled w-a-y before then..
>
> The pipes should be OK, as long as they're not copper (work hardening)
>
> H1K
>
>
rather help "moving up" rear calipers which tend to hang and cause excessive
wear/increased fuel consumption.
Rune
"Hairy One Kenobi" <abuse@[127.0.0.1]> wrote in message
newsvhCb.1625$FN.954@newsfep4-winn.server.ntli.net...
> "Wolfgang Pawlinetz" <me@privacy.net> wrote in message
> news:960jtvsqkrg5rtr6nmpod28tupggl38c07@4ax.com...
> > On Fri, 12 Dec 2003 01:15:22 -0000, "Hairy One Kenobi"
> > <abuse@[127.0.0.1]> wrote:
> >
> > >Theoretically, depending upon the materials used, it could shorten the
> life
> > >of the calliper seals.
> >
> > I politely disagree.
> >
> > The actual travel of the calipers when the ABS opens and re-applies
> > brake pressure is IMO a few hundreds of a Millimeter. The pressure on
> > the pad's fluctuates, but for that not a lot of travel is needed
> > anyway. This travel is IMO covered in the flexibility of the seals
> > itself, there's not much real relative movement there. If you look at
> > it the travel of the calipers is mostly caused by the wear of the
> > pads, making them thinner and the calipers moving out.
> >
> > I think the ABS control valve and the tubes running to the wheels will
> > vibrate but I haven't heard or read about mechanical damages to these
> > systems.
>
> I'm thinking crack propagation. That said, I would reverently hope that
the
> callipers had been overhauled w-a-y before then..
>
> The pipes should be OK, as long as they're not copper (work hardening)
>
> H1K
>
>
#19
Guest
Posts: n/a
Re: ABS question, mechanically oriented.
"Rune Skigelstrand" <skigel@hotmail.com> wrote in message
news:7dmDb.5738$n31.99494@news2.e.nsc.no...
> In my opinion triggering the ABS once in a while can't do much harm but
> rather help "moving up" rear calipers which tend to hang and cause
excessive
> wear/increased fuel consumption.
...and hitting the odd wall head-on at 60mph helps to give the front bumper
practice in the event of a "real" accident..? ;o)
(Quite apart from that, if a caliper "sticks" then it's more likely to be in
the retracted position, IMHO)
H1K
> "Hairy One Kenobi" <abuse@[127.0.0.1]> wrote in message
> newsvhCb.1625$FN.954@newsfep4-winn.server.ntli.net...
> > "Wolfgang Pawlinetz" <me@privacy.net> wrote in message
> > news:960jtvsqkrg5rtr6nmpod28tupggl38c07@4ax.com...
> > > On Fri, 12 Dec 2003 01:15:22 -0000, "Hairy One Kenobi"
> > > <abuse@[127.0.0.1]> wrote:
> > >
> > > >Theoretically, depending upon the materials used, it could shorten
the
> > life
> > > >of the calliper seals.
> > >
> > > I politely disagree.
> > >
> > > The actual travel of the calipers when the ABS opens and re-applies
> > > brake pressure is IMO a few hundreds of a Millimeter. The pressure on
> > > the pad's fluctuates, but for that not a lot of travel is needed
> > > anyway. This travel is IMO covered in the flexibility of the seals
> > > itself, there's not much real relative movement there. If you look at
> > > it the travel of the calipers is mostly caused by the wear of the
> > > pads, making them thinner and the calipers moving out.
> > >
> > > I think the ABS control valve and the tubes running to the wheels will
> > > vibrate but I haven't heard or read about mechanical damages to these
> > > systems.
> >
> > I'm thinking crack propagation. That said, I would reverently hope that
> the
> > callipers had been overhauled w-a-y before then..
> >
> > The pipes should be OK, as long as they're not copper (work hardening)
news:7dmDb.5738$n31.99494@news2.e.nsc.no...
> In my opinion triggering the ABS once in a while can't do much harm but
> rather help "moving up" rear calipers which tend to hang and cause
excessive
> wear/increased fuel consumption.
...and hitting the odd wall head-on at 60mph helps to give the front bumper
practice in the event of a "real" accident..? ;o)
(Quite apart from that, if a caliper "sticks" then it's more likely to be in
the retracted position, IMHO)
H1K
> "Hairy One Kenobi" <abuse@[127.0.0.1]> wrote in message
> newsvhCb.1625$FN.954@newsfep4-winn.server.ntli.net...
> > "Wolfgang Pawlinetz" <me@privacy.net> wrote in message
> > news:960jtvsqkrg5rtr6nmpod28tupggl38c07@4ax.com...
> > > On Fri, 12 Dec 2003 01:15:22 -0000, "Hairy One Kenobi"
> > > <abuse@[127.0.0.1]> wrote:
> > >
> > > >Theoretically, depending upon the materials used, it could shorten
the
> > life
> > > >of the calliper seals.
> > >
> > > I politely disagree.
> > >
> > > The actual travel of the calipers when the ABS opens and re-applies
> > > brake pressure is IMO a few hundreds of a Millimeter. The pressure on
> > > the pad's fluctuates, but for that not a lot of travel is needed
> > > anyway. This travel is IMO covered in the flexibility of the seals
> > > itself, there's not much real relative movement there. If you look at
> > > it the travel of the calipers is mostly caused by the wear of the
> > > pads, making them thinner and the calipers moving out.
> > >
> > > I think the ABS control valve and the tubes running to the wheels will
> > > vibrate but I haven't heard or read about mechanical damages to these
> > > systems.
> >
> > I'm thinking crack propagation. That said, I would reverently hope that
> the
> > callipers had been overhauled w-a-y before then..
> >
> > The pipes should be OK, as long as they're not copper (work hardening)
#20
Guest
Posts: n/a
Re: ABS question, mechanically oriented.
"Hairy One Kenobi" <abuse@[127.0.0.1]> wrote in message
news:aorDb.4179$526.28889@newsfep4-glfd.server.ntli.net...
>
> (Quite apart from that, if a caliper "sticks" then it's more likely to be
in
> the retracted position, IMHO)
Respectfully disagreeing, IME, there's always enough hydraulic pressure to
push the pistons *out* and very little in terms of piston seal flex to bring
them *back*. That's why the simplest visual indicator of a stuck piston is
excessively worn pads on that wheel.
--
C.R. Krieger
(Been there; broke that)
news:aorDb.4179$526.28889@newsfep4-glfd.server.ntli.net...
>
> (Quite apart from that, if a caliper "sticks" then it's more likely to be
in
> the retracted position, IMHO)
Respectfully disagreeing, IME, there's always enough hydraulic pressure to
push the pistons *out* and very little in terms of piston seal flex to bring
them *back*. That's why the simplest visual indicator of a stuck piston is
excessively worn pads on that wheel.
--
C.R. Krieger
(Been there; broke that)