[Spits] Rear suspension modification question

[Joe Curry]

Chris,
I don't recall seeing anything like you describe in the books I have from
Kas.  But it all depends on which suspension you are working with.

On the standard early Spit swing axle, the two control arms in the rear
suspension are the spring (forming the upper element) and the axle (forming
the lower one).  Since the position of the suspension has a lot to do with
the camber that is achieved, lowering the car by reducing the spring arch or
by adding blocks between the spring and the diff are the only two choices
you have short of lengthening or shortening either the axles or spring.

Kas recommends reducing the spring arch to 3.5" which does a good job of
increasing negative camber and lowering the car.

I have also seen some photos of people who have drilled the uprights to
place the spring eyelet lower on the upright and thus changing the
relativity between the upper and lower control elements.  I haven't seen any
data on what effect that would have and am not sure that I would want to go
that route.  It seems that might have some odd effects on how the suspension
works.

If you get any actual data on that or any other more radical modifications,
I'd love to hear about it.

Cheers,
Joe

----- Original Message ----- 
From: "Chris Crisenbery" <ccrisenbery at fellerfinch.com>
To: <spitfires at autox.team.net>
Sent: Monday, June 25, 2007 7:47 AM
Subject: [Spits] Rear suspension modification question


> Dear Listers,
>
> I'm looking at making an adjustable rear shackle to be able to adjust
> the rear tires camber.  I believe Kas Kastners book has a picture of an
> adjustable shackle.  I'm talking about the piece that attaches at the
> end of the spring and bolts to the rear axle trunnion and lower shock
> mount.
>
> Have any of you done this modification?  I believe the Kas detail shows
> the 2 "eyes" being whacked off of the shackle and a rod end welded onto
> each side to take it's place.  I believe when you screw the rod ends up
> you will lengthen the overall length of the shackle and it should raise
> the car by having less camber on the rear wheels.
>
> I would be interested in any pictures or experience in doing this mod.
>
> Thanks
>
>
> ___________________________
>
> Christopher E. Crisenbery, P.E.
> Feller, Finch & Associates, Inc.
> 2797 Spring Arbor Rd., Suite B
> Jackson, MI 49203
> p/n (517) 783-0710
> fax (517) 783-0711
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