Re: ABS

[Phil@sievers.demon.co.uk (Phil Payne)]

In message <941208223749_1064996@aol.com> OREO447766@aol.com writes:
>>       "ABS will, of course, almost always LENGTHEN your braking
>>        distance.  Does anyone 
>>        here ever switch it off - and if so, why?"
>     Phil, I'm concerned about the above statement. This may need some
> clarification. ABS' pulsing action to modulate pressure will almost always
> reduce braking distances, it also has the added advantage of allowing the
> driver to concentrate on steering.

>      Disclaimer: None of my rigs are ABS equipped, so these words are based
> on textbook knowledge, not road tests. 

This is now my eighth year driving mainly ABS-equipped vehicles.  Four 
separate Ford Granadas and a ur-quattro.  My experience with the Granadas was 
that ABS lengthened braking distances by 10% to 30%, but increased steerability 
and predictability.  I've verified this with the ur-quattro, where you can 
actually disable the ABS.

I also had the benefit of Audi's thoughts during a session at the Weissach test 
track, when "Project Tetra" was being developed (1982/3).  This was later 
released as the "syncro".  The team there said that the shortest braking 
distances were achieved without ABS, and the Audi "quattro driving course" (two 
days free for early 80Q buyers) taught drivers to make a downward sweeping 
movement with their right hand. The idea was to hold the index and middle 
fingers a little way apart and pull out both differential locks in one 
movement.  They were also VERY strong on the "brake early and hard" principle.
 
Anyway, I now drive with ABS engaged at all times.  But the ONLY benefit I 
expect is better control under braking, not better braking.  I'm now so used to 
hitting the brakes as hard as possible, as soon as possible that I don't 
believe I would react to a lockup as instinctively as I would have done ten 
years ago.  

Phil Payne
Sievers Consulting UK
Vice Chair, UK Computer Measurement Group
+44 385 302803 Fido 2:2503/415  CIS 100012,1660