> Although if you completely lift the rear, like under hard braking, it
> isn't going to do anything to keep the wheels from tucking in. So if
> you go into a turn under hard braking, you'd still be tucking the rear
> under. I don't know for sure, but I'd really think a camber compensator
> would be a better way the spend the money.
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Let's kinda set the record straight. The problem is not roll stiffness in
the rear on early Spitfires, otherwise the factory simply would have bolted
on a hefty rear roll bar and been done with it. The problem with all swing
axles is roll "center" or the imaginary point above the rear axle that the
car wants to roll about. The ideal would be somewhere below the ground. On
swing axle cars the roll center is a few inches above the top of the
differential. The front roll center is much lower so that if you were to
draw an imaginary line between the two centers you would have a line at an
angle, with the front lower than the rear. Thats why the rear has a
tendency towards pitching its self in the air (it wants to roll first) with
the axles hanging in their arcs (being "swing" axles they have no where else
to go) The purpose of the "swing spring" is to RELOCATE the roll center
somwhat lower, transferring more of the cars weight back to the rear and
preventing the rear from "jacking up". The ideal setup is to have both roll
centers at the same point somewhere below the ground, seldom achieved. Roll
bars don't change the roll center, just the tendency for the car to roll, or
its roll stiffness.
Barry Schwartz
Bschwartz@encad.com (work)
Bschwart@pacbell.net (home)
(San Diego)
70' Spitfire (major surgery almost done) , 72'-V6 Spitfire (daily driver)
70'GT6+
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