"Dave Hinz" wrote in message
...
On Tue, 14 Dec 2004 18:54:36 GMT, patrick conroy
wrote:

"Dave Hinz" wrote in message
...

Are you claiming that you can brake better in bad conditions than ABS
can? Can you describe specifically what condition you believe this
to be true for?

Not to jump into the middle of this arg - but IIRC, one of the rags (C&D
and
R&T) had some fun here. They had run across some Driving School where the
instruction was to "lock 'em up and lock 'em up hard." I think they
brought
in some "semi-pro" drivers and tried to see who could stop shorter with
the
most control. A pro who put the foot down to the limit of locking, or an
amature who just stomped on the pedal.

Right. I saw a similar study, not sure if it was the same.

The conditions were dry - and the locked up brakes consistently stopped
shorter.

Well, the ABS "stomp hard on pedal and leave it down" wasn't technically
locking up the brakes.

A very good driver can "threshhold brake", where he applies pressure to
the foot pedal _just_ shy of losing friction. The problem is, he has one
foot pedal, and there are four wheels, each of which are going to have
a maximum braking before they start sliding/skidding. One actuator, four
outputs. He can only be as good as the slippiest wheel.

ABS, on the other hand, detects slip and modulates the brake pressure
to specifially that wheel. It's doing on each of the 4 wheels what the
really really good driver can only do on the slippiest of them at best.
So, for the one wheel with the least grip, it's as good as an expert
driver; for the other 3, it's making adjustments that that driver just
can't get to, because he doesn't have 4 left feet or the response time.

The _only_ situation where ABS can be beat by an expert driver is
in a slush/heavy snow situation, where you _want_ the tires to slide
so the snow gets pushed in the front of the tires as in a snowplow,
but of course you can't steer when that's happening.

when i was auto-xing, there are LOTS of times i didn't want the abs to kick
in, mostly when i wanted the rear of the car to step out to turn the car
faster.

I had driven a lot of miles on ice and snow, and when my first vehicle
with
ABS showed up, I spent several hours in a empty parking lot retraining my
foot to let the system do it's job.

Fun times. Did the cops stop over to see what you were up to as well?
I explained, and they said "have fun" and left. Being in my 30s helped,
I'm sure, they were probably expecting a 17 year old or something.

It's still hard to get your head around "I can steer, I can still
steer..."

There is some very interesting vector force stuff going on when you're
steering while it's in ABS mode. Saved sheet metal damage for me once
already, I'm certain.

Dave Hinz