spitfires
[Top] [All Lists]

Re: Swing spring / camber compensator

To: Bill Birney <bill.birney@bigpond.com>
Subject: Re: Swing spring / camber compensator
From: Joe Curry <spitlist@gte.net>
Date: Tue, 13 Jun 2000 08:05:45 -0700
BIll,
I guess we will just have to agree to disagree,  But the sway bar in tying the 
rear wheels together it eliminatyes some of the
"independence" of the rear suspension.  And in doing so, reduces (maybe not by 
a great amount, but some nonetheless) the potential for
wheel tuck.  Let it be known, however that I am not by any stretch of the 
imagination recommending a rear anti sway bar for that
purpose.!! 


Your statement about the Z-bar not requiring any more force than mounting the 
camber compensator is patently incorrect.  Because if any
force is required in twisting the bar (which there is) is more than that 
required in installing the camber compensator.  The CC is
designed to have very nearly zero preloading.  It can be adjusted to increase 
the preload but but it is not recommended to load it up
more than 1/2 inch which is not very significant and can be done by one person.

By the Way, Kas Kastner told me that Spitfires don't Jack up.  He explained to 
me the difference but I've since forgotten the specifics
on his explanation.  His preference of terms is Wheel tuck and says it is an 
oft misunderstood and misused term.

Regards,
Joe Curry


Bill Birney wrote:
> 
> Joe et al,
> 
> > Drooping is a passive thing
> 
> Tuck in, Tuck under, I'm talking about massive positive camber.....
> 
> > anything to compensate, the unloaded wheel will fall down and in the
> process, TUCK UNDER. ...
> > But the rear anti sway bar also performs somewhat the same function.
> 
> Again Joe, sorry to disagree, but the anti roll bar will not help really at
> all. The problem with the Spitfire rear suspensiion is the roll centre, this
> causes the back of the car to actually 'jack up', as traction is lost, this
> means that NO WHEELS ARE SUFFICENTLY LOADED to counteract the action of the
> spring.
> 
> The swing spring counteracts this by effectively lowering the roll centre of
> the rear suspension.
> 
> So what you need to do to stop this is either:
> 
> (1) never ever get into a high speed unloaded condition ... probably not
> very realistic. OR
> 
> (2) have some way of resisting the motion of the spring action. (Your camber
> compensator or the Z bar)
> 
> > Z-Bars were declared illegal by the SCCA back in the 60's.
> 
> Still a good fast road option, and most definitely not illegal here (the
> athourities in fact strongly recommend the use of such a device). I would
> say that I have a fair bit of experience at driving a Spitfire at speed, and
> have still had a very hairy couple of moments when things have 'jumped out'
> infront of the car!
> 
> In those cases the old "brake early, get back on and turn in" maxim doesn't
> do you a lot of good. The feeling as the back end climbs into the air, and
> you start to exit backwards into the scenery with the right foot buried in
> the accelorator, praying it won't trip over something is not one I want to
> repeat too often!!!!!!!
> 
> >  but in theory they should be very effective.  But to do their job they
> need to be preloaded with a fairly > significant
> > amount of force.  That makes their installation somewhat precarious.
> 
> I can say in practice, not just theory (someone was after one, I have one in
> the shed, no longer needed as the car will be gaining a copy of the GT6's
> new rear end, Subaru diff and CV driveshafts, transport from Oz could be
> prohibitive though!). As for the force, there is no more requirement for
> force that your camber compensator, it all depends on the degree of wheel
> control you are after. They are basically a bolt on and wind up modication.
> 
> Bill Birney

<Prev in Thread] Current Thread [Next in Thread>