>
> Date: Thu, 26 Aug 1999 00:42:30 -0700
> From: Alan Dahl <adahl@eskimo.com>
> Subject: Big Swaybar Woes, cause found?
>
> ...if you stop and think about how a swaybar works
> you realize that the
> stress should not be all that much more, certainly
> not enough to tear the
> bracket.
>
I'm not sure I agree, Alan. Swaybar stiffness varies
with the 4th power of the diameter, so the difference
can be considerable. The 1 1/8" hollow bar Dan is
using can easily be exerting over 70% more force on
the brackets than the stock 7/8" solid bar.
>
> It appears
> that under extreme conditions the A-arm can move far
> enough to contact the
> sway bar. When this happens I suspect that the
> entire weight of that corner
> of the car (or at least a large percentage of it) is
> momentarily
> transferred from the spring to the swaybar
I wonder if the 'extreme conditions' would include
jacking up the car to change tires...anyway, it should
be simple to check by sticking some Plastigage or
something similar on the sway bar. I would think this
would happen on the inside wheel so weight would
already be transferred off it, but I guess the force
of the compressed spring could put extra stress on the
bar brackets.
BTW, I had a look at the sway bar brace RB sells and
I'm _very_ skeptical of its effectiveness. It has a
crossbar between the brackets to distribute side loads
and a pair of blocks that fit between the brackets and
frame rail to take compression loads. However, if
either of those were the problem I'd expect the sheet
metal brackets to buckle, not fracture. The cracking
on Dan's car seems to be consistent with tension
loads, which I don't see the RB brace helps at all.
(I'm just a dumb computer grunt, so any mechanical
engineers out there feel free to correct me.)
Craig Blome
Bid and sell for free at http://auctions.yahoo.com
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