Re: shackle reversal thoughts

[tsm1@domain.elided (Tom Mandera)]

>I'll throw my $.02 into this discussion, but since my first hand experience
>is all Jeep, you may want to skip over this.

And I'll see what else I can remember from past discussions (no experience
here... YET)

>As Tom mentioned, the spring eyes want to be the same verticle distance
>from the ground (or some datum) when finished, while this is not 100% kill
>ya if ya mess up, it ought to be as close as is easy, you can use slightly
>shorter shackles to twist the front yoke up instead of shims, but beware of
>going to far. Obviously the fronts need to be even with each other at both
>ends too.

If your springs are NOT "level", you'll get some strange behavior when the
springs compress/uncompress.. typically the spring compresses UPwards, but
if you "tip" the spring at rest, say the front is higher than the rear, the
spring will compress Up and REARWARD, making the old "tire hits the backside
of the fender" problem even worse, and possibly hurting your overall
articulation setup.

Granted, as Terry mentioned, it would take a fair bit of un-levelness to
cause any big problems, but this is why.

Also keep in mind the drag link... if you have any type of lift, it's
probably not very happy with you to begin with.. then you want to tip the
axle end of the drag link and put it at an angle *too*??  Not only would we
be making the ball joints in the drag link ends to work harder than ever,
but your steering mechanism isn't exactly parallel like it should be, either.

As I think about this, turning the knuckles causes this "problem" too.. but,
again, we're talking 4 degrees with a knuckle twist, and provided your
springs aren't too far off, they won't be causing any radical changes here
either..

The short of it is, don't try to bolt the springs just below the front cross
member and use a custom rear shackle.. you won't like the results!

>Your axel will now move up and back vice up and forward so the axel should
>end up slightly forward in the wheel well from where it is now, I use an
>reassemble the pack. I've seen it done both ways and even combinations of
>the two. The kits that are available for Jeeps now all use the fron tower
>to re-locate the spring forward, FWIW.

Willie Worthy had some real problems with his reverse shackle on TONTO.. he
said he re-did his front spring towers two or three times to get things
dialed in so the tires stopped trying to sit in the cab..

Terry, what about lift springs?  I've seen some measurements taken, and it
seems lift springs, eye to eye, are shorter than the stockers.  My stock '77
front end  springs seem to be about 44" long (rough tape measure job before
work), while a set of Superlift 4" springs are rumored to be 41" long.. Jim
Weed's reverse shackle plans space the spring eyes 43"..

I'm wondering if lift springs, being a little shorter, make up for this inch
or so of forward relocation.

Also, I'm not sure if turning the springs around front/back helps the
situation, or if anything strange happens because of the spring rates.  I
know people use this tactic on the rear end to re-center the tires a little
further back.

>Tom was, again, dead on with the need for a cross brace between the towers,
>would tie the towers hard together and not make them boltable, but there
>could be some value in that, just be sure to monitor the bolt holes for
>wallowing out over time.

I wasn't sure if I wanted it fixed or not.  An informal poll at the NWBinder
Roundup showed half the trucks with and half without the brace (those that
had reverse shackles, of course!)  I couldn't determine if there would be a
time that I *want* those towers to flex or not..

But, now that I've heard.. it gets WELDED together.. besides, what's another
1" on the RTI anyhow compared to frame stress..

-Tom Mandera, Helena MT
http://www.tmcom.com/~tsm1/scout
'72 and '77 Scout IIs