Help, new wheels scraping on '85 Coupe GT addendum:

[Fisher, Scott]

Ken Keith gets it on the money, I'll bet:

> This may have already been addressed, but the panhard bar moves 
> the axle to _one_ side as the car is lowered, or as the wheels 
> move up toward the body.  Ideally, one may want to have an 
> adjustable heim (hime?) joint at the end, to center the axle 
> at the new ride height.

You know... when I first read the posting about the car with an off-center
rear axle, I wondered about the Panhard rod and couldn't remember which end
was connected to the car and which to the axle, so I didn't say anything.
But of COURSE -- that's a known behavior of a Panhard rod, that the
body-to-axle alignment changes as the ride height changes.  I'd be willing
to bet a power-window switch (works, just needs cleaning :-) that the right
end of the rod connected to the axle and the left to the chassis, yes?  A
few quick sketches seem to suggest that's the orientation that results in
moving the axle left under compression... unless I've got it exactly
backwards, of course. :-)

Anyway, this is almost certainly another reason my undropped car *doesn't*
rub and all the dropped cars described on the list *do*.  Next time it's
reasonably dry (or I'm in clothes that I don't mind wearing while crawling
in wet leaves), I'll peer under the CGT and see if I guessed right about the
geometry of the Panhard rod.  But either way, for those of you who have
lowered your CGTs, you *will* have changed the Panhard rod geometry (as well
as the rear trailing arm geometry).  That's not necessarily a bad thing, but
it IS something to keep in mind.  There's almost no change you can make that
affects only one part of the car's behavior.

(Doesn't explain the ur-Q that was mentioned as rubbing, however... that's
gotta be rim/tire width and offset.)

Also, to chime in further on the subject of tweaking ride height with
shocks: some brands of shock *are* known to change a car's ride height.
This was well documented in the early '90s about Tokico Illuminas; I ran a
set on my autocross GTI and the car was slightly taller than a friend and
codriver's GTI with Boge shocks.  Both cars were on stock springs and the
same tires/wheels, so the only difference was the shock choice.  The main
advantage that the Illuminas gave, however, was that I could tune the rears
stiffer than the fronts, which changed the car's corner-entry
characteristics to make it feel as though it had more (or at least some)
oversteer in the early part of the corner.  Just the change you want to make
in a noseheavy autocrosser, where getting the car to "point" quickly in a
corner is half the battle.

One thing I enjoy about the CGT is that, for a FWD car, there's far less
understeer than I'd expect from that looooong 5-cylinder engine hanging off
the front.  Kudos to Audi for getting the rear suspension as good as it is;
it's a joy to pitch this car into a corner hard, get on the gas, have the
weight transfer to the rear and feel the car yaw outward into something that
feels very much like a RWD car's drift.  That's the main reason I'm not
planning on putting in shorter springs -- since this will probably never be
a track car, I don't want to upset the rear-end geometry.  

--Scott Fisher
  1983 CGT
  1993 100CSQ