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Re: Why new leaf springs may be a waste

To: vscjohn@iamerica.net
Subject: Re: Why new leaf springs may be a waste
From: Barney Gaylord <barneymg@ntsource.com>
Date: Tue, 11 Aug 1998 05:09:19
At 03:52 PM 8/10/98 -0500, John Roper wrote: 
>I ran a B is DSP with substantial success for several years. .... I
stacked two front bars, used heavy front springs, built in much negative
camber, lowered the car 2" all around, and took the two small leaves out of
the rear springs. .... Could pitch and catch, and steer on the throttle.
.... I did try a rear bar and found it made the car very twitchy.

Yep.  If the the car is reasonable in handling to begin with, increasing
the rear roll stiffness will induce oversteer, leading to twitchy on
switchbacks and sudden steering manuvers.

Unfortunately, nearly all MGs (as stock) are too stiff in the rear to begin
with.  The fact that they aren't terribly twitchy in stock form has to do
with the limited lateral traction of the stock tires, and the fact that
large amounts of body roll in the turns induces a nasty camber error on the
outside front wheel that can lift part of the tire tread off the ground.

Increasing front roll stiffness will continue to reduce push (understeer)
until you can keep the inside rear tire on the ground in hard turns.  Once
all four tires are firmly planted on the pavement, additional increase in
front roll stiffness will once again begin to induce more push.

And I intend to remain in Stock class, so everything you did for Street
Prepared class, I can't do, except for the front sway bar(s) and stiffening
the existing shocks.

I think I would put down good money to try a 7/8" front sway bar in place
of my current 3/4" bar, but so far I haven't found one to fit the MGA.
Here a little bit goes a long way, because the tortional stiffness of the
bar increases as the fourth power of the diameter.  The 7/8" bar would be
85% stiffer than the 3/4" bar, and nearly 4 times as stiff as the factory
optional 5/8" bar. Of course these figures would be tempered somewhat by
the bending action of the angled ends of the bar where stiffness only
increases as the square of the diameter.

Your idea of stacking two bars sounds interresting, but it may be easier
(and maybe cheaper) to have a single larger bar custom fabricated. 

Barney Gaylord
1958 MGA with an attitude


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