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Big Swaybar Woes, cause found?

To: autox@autox.team.net
Subject: Big Swaybar Woes, cause found?
From: Alan Dahl <adahl@eskimo.com>
Date: Thu, 26 Aug 1999 00:42:30 -0700
At 08:56 AM 8/25/99 -0500, you wrote:
>Some of you Miata guys need to be raising hell with the factory to get this
>fixed. This car has now been in production for 10 or 11 years. It shouldnt be
>that hard to beef the front of this car.

I think I may have figured out what is causing the brackets to break. I've
noticed that there have been few if no reports of broken brackets with the
OEM swaybar but several with larger bars. It has been assumed that this is
caused by the larger bar transferring more stress to the swaybar bracket
but 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.

A hint was that several Miata owners report "clunks" from the front
suspension but no evidence of any loose items or damage can be found. I too
had this problem with the 1" bar on my Miata and started to look around for
the source of this clunk.

Finally I noticed that the swaybar had a little divot in it where it had
appearantly come in contact with the lower suspension A-arm. 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. If this happens enough times
with enough severity the swaybar brackets are bound to break. I suspect
that with the smaller stock bar there is little or no contact at full
deflection but as soon as you increase the swaybar size you start to get
contact.

I could be all wet here with my analysis and I would be glad to hear from
people what their opinions are on my theory but IMHO this is a likely
expanation for the broken brackets.

What do you think?

- Alan Dahl
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  ___   ____     Alan Dahl                  | home: adahl@eskimo.com
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