RE: UFO Power

["Buchholz, Steven" <Steven.Buchholz@kla-tencor.com>]

... well, you can say that in hindsight as manufacturers moved on to larger
wheel diameters on their stock cars since then.  As I tend to recall 15" was
about the largest standard wheel diameter available back then ... Audi could
have just as well been concerned that the customers would scream about
having to replace expensive 16" tires if they did not become a new standard.
Chances are that they would have had to go to a lower profile tire if they
went to a larger diameter, which may have brought undesired consequences in
the roughness of the ride for the car.  Every car manufacturer has to look
into their crystal ball a bit when they figure out how to build a car, and
the decision on the UFOs was probably made a few years prior to when the
cars were actually available.  If it wouldn't have been for the warpage
issue I doubt that there would be any significant complaint about the UFOs
at all.  

Speaking of scientific evidence ... I've seen a lot of numbers guesstimated
as to what the unsprung weight penalty of having the UFOs was ... but I
don't recall ever seeing the real numbers on the difference (apologies in
advance if my memory is failing me).  As far as the stopping power of the
UFOs as compared to conventional brakes it is simple physics.  Given that
all other variables are held constant, the simple change from a conventional
caliper to an internal caliper will result in an increase in swept area as
well as the other characteristics that Phil Payne mentioned.  I can also
tell you that I have had owners of converted V8s drive my car with the stock
UFOs tell me that there was a significant enough difference for them to feel
... oh, perhaps it was that extra 0.5" of wheel width that the '91 has over
the '90 ... that and those Goodyear Eagle tires ...

Steve Buchholz
San Jose, CA (USA)

	----------

	At 06:12 PM 3/12/99 -0500, Graydon D. Stuckey wrote:
	>	Just to give a comparison for the UFO brakes vs the regular
brakes, 
	>My 4000 pound V8 with stock UFOs stops much faster than my ex 3350
pound 
	>5KCSTQ with ATE powerstops and Performance Friction pads.  Even if
I 
	>thought they were equal, the difference in weight alone is enough
to 
	>prove that the UFOs are far superior.

	Hi,

	I would love to see some scientific evidence of this rather than
anecdotal
	evidence. It is not that I do not believe you but rather that it is
very
	difficult to judge these things without doing back to back, blind
tests in
	a controlled environment. What you are saying is possible but it
could also
	be the case that the UFOs had better pedal feel but no shorter
stopping
	distance. It could also be that your tires had changed or worn or
the
	coefficient of friction of the road surface was not the same. The
devil is
	in the details. Personally, I would rather have had larger wheels
with
	larger conventional rotors than the UFOs and 15" wheels. I doubt the
	additional weight of a 16" wheel and tire combination would be more
than
	the difference in weight of the UFOs and conventional brakes.

	Regards,

	Clifford Ilkay