Strut Tower Brace Design Revisited
b.benz at charter.net
Sat Feb 26 09:39:31 EST 2005
Thanks George, for belatedly sharing your "enhanced" strut brace pictures
and design rational with the list. IMO, A nice implementation of a flawed
enhancment concept, which you have justified and I must critique as follows:
"A solid bar was used, instead of EMT, to eliminate the negative moments
which could induce metal fatigue through flexing. While the EMT does prevent
the two towers from flexing toward each other (wheel going up - positive
moment), it does not prevent the negative response (when the wheel is
traveling back down - negative moment) from flexing the towers away from
each other. The familiar tear in the right tower flange appears to be
fatigue related, and the solid bar reduces the question of lateral loading
in either direction. My thanks to Bernie for the overall idea."
George, as we discussed when you were building your brace, there is no
tension force exerted on this strut brace! You imply that the major forces
to which this bar is subjected are caused by vertical suspension
deflections. Not so! The principle force is that component of the
transverse cornering force exerted by the strut rod, an exclusively
compressive force on the brace.
Relative to your hang up on vertical suspension deflection caused "moments",
the resultant forces are transmitted thru the spring directly to the strut
tower, not thru the strut rod. In the bump direction this would result in
a slight moment tending to bend the tower inward. In the rebound direction,
you would have a reduction of this inward moment, but never going negative,
even with the wheel off the ground.
In implmenting your theory George, you should have installed a tower brace,
not a strut brace, inasmuch as the forces that you were trying to brace
against are tower related, not strut rod related.
Glad that the brace worked for you, just a cost and weight overkill, IMO.
> From: George Sidman <sidman at montereynet.net>
> Since a few of you have asked, my enhanced strut brace
> pictures are at www.gsidman.com. Yes, Bernie, I used a solid
> bar. Lest I start a new contentious thread on this time worn
> subject, let me simply state that since I installed it,
> handling has been much tighter, and tire wear uniform. And,
> the regular front end alignment has not been needed.
> GEORGE SIDMAN, Chairman
> sidman at webloq.com
> Monterey, California
> 831 760-0168
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