I recently read that GMs ABS for P/Us is poorly designed.
Mike
----- Original Message -----
From: "Alex Avery" <aavery@rica.net>
To: "Chris Saulnier" <CSaulnier@enerconmaine.com>; "Roadster List (E-mail)"
<datsun-roadsters@autox.team.net>
Sent: Thursday, June 07, 2001 11:20 AM
Subject: More ABS griping
> I'm not a fan of ABS either. I've driven my wife's '97 GMC 2500, extended
> cab, 5th-wheel hitch (not a duelie) mega truck daily 30 miles to work and
> back for the past 4 years and I love it---EXCEPT for the darn ABS brakes.
>
> Every time I'm stopping on sand or gravel or even simple bumpy surfaces
> where the wheel will lift off the pavement for a split second (not panic
> stops, just plain-old, every day brake use) the ABS kicks in and I find
> myself traveling 10, 20 or even 30 feet farther than I intended. These
> same intersections/road sections are fine in my Ford Contour that doesn't
> have ABS. This can be very dangerous when you're driving in dry
conditions
> and haven't factored in this unexpected distance into the equation. From
> what I can tell, ABS hasn't shortened my braking at all--totally the
> opposite--but worse, I don't feel I've gained any additional steering
> control or other advantage in return. What are we getting for this
> expensive option, other than unpredictability?
>
> Unsatisfied with the unfulfilled promise of ABS.
> Alex Avery
>
>
>
> At 09:30 AM 6/7/01 -0400, Chris Saulnier wrote:
> >I'm not a big ABS fan either, I can see where a full modern ABS system
would
> >be a great driving aid, but the training of how to use it is so
lacking...
> >Personally I prefer to control brake lock with my foot, and not give it
to
> >electrons. Heheheh, can you imagine a Lucas ABS system? I'd never drive
> >that puppy!!!
> >
> >Anyhow, here is what the State of Maine discovered after ABS systems
started
> >to be prevalent. The number of single vehicle "off the highway and into
the
> >trees" accidents started to rise dramatically. When they looked at the
> >numbers, the majority of vehicles involved in these type of accidents
were
> >ABS equipped. Further study showed that most of the accidents involved
> >evasive action, ie: coming up on an animal in the road at night. After
some
> >vehicle testing, it was found that nailing the brakes and swerving (to
avoid
> >an object in the road) at the same time caused the ABS systems to fully
> >release the brakes. Apparently the physics of potential lock-up and slip
> >angles caused the system to not apply the brakes at all during the swerve
> >action. When the system recovered, the vehicle was headed off the
pavement
> >and into low traction surfaces (grass or loose dirt). Here, the system
> >would modulated correctly, but due to the lowered surface friction the
car
> >would usually hit something before it stopped on the brakes. In this
> >specific case, I would certainly prefer the non ABS system, to allow
burning
> >off speed on a high traction surface.
> >
> >Chris of Maine "one last post..."
> >
> >'71 wagon "junkbox" driver DR#5 (LZ22 :>)
> >'72 4dr - project DR#6 (V8)
> >'69 1600 Bluebird SSS 4dr 1/24 scale
> >'70 Bluebird Coupe 30th Anniversary Edition 1/60 scale (thanks Lou!)
> >
> >> -----Original Message-----
> >> From: Brian Hollands [mailto:bholland@hayes.ds.adp.com]
> >> Sent: Wednesday, June 06, 2001 6:51 PM
> >> To: Patrick P. Castronovo
> >> Cc: Datsun Roadster Mailing list
> >> Subject: RE: ABS
> >>
> >>
> >> Some of the early ABS systems are easily fooled but newer
> >> systems are more
> >> sophisticated. The good ones will sense the speed at each
> >> wheel and will
> >> relieve pressure on that brake until the wheel begins to spin
> >> again then add
> >> pressure until it starts to lock and again release. They do this from
> >> several to many times each second. So they keep the wheel
> >> near its point of
> >> lock up regardless of pedal pressure so that the stopping
> >> distance will be
> >> as short as the available traction will allow. One of the
> >> problems that has
> >> also occurred is related to driver training with the system. A police
> >> officer was killed (If I remember correctly in a Caprice) due
> >> to improper
> >> training on ABS system use. The pedal will sort of vibrate as the ABS
> >> system cycles between adding and relieving pressure from each
> >> brake. This
> >> PD had trained it's drivers with the old "pump the brakes" bit which,
> >> especially with an ABS system only increases the stopping
> >> distances. When
> >> the driver felt the pedal vibrating under his foot he interpreted the
> >> problem as wheel lock and released (began to pump) the pedal
> >> ultimately
> >> causing him to enter a corner too fast and lose control.
> >> The pedal does feel weird when the ABS engages and that can be
> >> disconcerting.
> >> Brian
> >>
> >>
> >> -----Original Message-----
> >>
> >>
> >> I have heard some horror stories about the ABS Brakes. They
> >> do not stop a
> >> car on ice or sand or Gravel. Any loose soil that allows it
> >> to slip and the
> >> brakes release. Pat
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