New rear stress bar

[brett at netacc.net (Brett VanSprewenburg)]

At 9:21 PM -0800 3/3/04, T. Reed wrote:
>Several years ago I remember reading about a group of mechanical engineers
>that set up what I think were piezoelectric sensors on an A1 VW (a
>Rabbit?) to see if the shock towers were really flexing during hard
>cornering.
>
>I think they observed movement of around 1/16" during full-lock parking
>lot turns at 5-10 mph. I can't recall the rest of their findings.
>
>As far as subjective feel - I too have noticed a difference from the front
>bar(s) - both the upper and the lower made a perceptible difference on
>my mk2. I have no experience with the rear bar.
>
>I wouldn't classify them as "must", but they certainly help the front end
>feel tighter. And they just might keep your shock towers from cracking.
>
>Then again, these effects might just be due to added weight up front..
>:)
>
>-Toby
>

Yep, your right.  What they found out was that the top of the *front* strut
tower moved significantly enough that an attempt should be made to
control (or restrain) them.  While at the rear, they moved far far too
little to bother with a cross bracing type of design, let alone trying to
just brace the top of the shocks (which is a total joke, and I don't even
feel like going into at the moment...).

BTW, this study is the only non-subjective evidence I have ever heard of
regarding the chassis flex of A1 cars.

Here are my subjective observations regarding front chassis reinforcement:

I changed out my lower bars for Autotech 22mm/25mm bars: Car cornered better,
faster speeds, more confidence.

I added an upper front struct brace (I don't care if it does have a 
"bend" it's not
flexible in the direction it's meant to reinforce).  I was totally 
shocked at how
much flatter and more stable the front of the car seemed.

Every time I broke an Autotech / Stock style front sway bar bracket, 
I could feel
it as a subtle loosness in hard cornering.

Again, all purely subjective, but pretty similar to other peoples 
experiences.  I
have considerable doubts regarding the effectiveness of a non-triangulated rear
bar having any significant effect.  I believe that I have read enough 
independent
(subjective) postive observations of triangulated rear bars to note 
that it probably
has some impact.  Too bad the piezoelectric sensor dudes can't do an
experienment.  Bet McGarvey would try it though... :-)

==Brett