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Extended shackle with the 57" swap good or bad?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by zakk, Sep 23, 2002.

  1. zakk

    zakk 1/2 ton status

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    Extended shackle with the 57\" swap good or bad?

    I am sure this has been discussed among the "high end" suspension guru's, but i am only slightly smarter than a dumb rock and need it speeled out for me /forums/images/icons/grin.gif

    Ok, I have ORD's shakle flip hangers and i am going to reverse mount them. so i will be able to run 55" springs in the stock location. i have two options

    1) Redrill the holes 2 in. back and run the stock shackle

    2) Keep the hanger in the stock location and run 2" longer rear shackle

    I read that a 20* rear rake of the shackle is benifical (why?),

    Would option #2 be better? why/why not?

    Thanks in advance!
     
  2. BadDog

    BadDog SOL Staff Member Super Moderator Author

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    Re: Extended shackle with the 57\" swap good or bad?

    Honestly, I think you will probably need to relocate the hangers back a bit. How far depends on what *effective* spring rate you want. Some don’t move them and let the shackle angle make it up. But, that effectively lowers you spring rate considerably. It mostly has to do with force vectors and something called “jacking”. I, along with Donovan and Twizted, made a rather long post on this quite some time ago. Force vectors will be pretty obvious if you look at what happens when the suspension cycles. Same for jacking. Blasted site is screwed up (SQL errors all over) and I can’t find the old post. I’m too tired to type it all in tonight, I’ll try to find it tomorrow…
     
  3. m j

    m j 1/2 ton status

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    Re: Extended shackle with the 57\" swap good or bad?

    longer shackles are a good idea no matter where the hangers are.
     
  4. zakk

    zakk 1/2 ton status

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    Re: Extended shackle with the 57\" swap good or bad?

    and why would that be? i am suspension illiterate, please elaborate /forums/images/icons/smile.gif
     
  5. BorregoK5

    BorregoK5 1/2 ton status

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    Re: Extended shackle with the 57\" swap good or bad?

    With the Ford 57's a 4" shackle is a little short to accomodate the full range of compression and free arc that they can provide. A longer shackle will also keep your spring rate more equal through the range of motion than a shorter shackle due to the larger circumference which the spring eye travelsl.
     
  6. MNorby

    MNorby 3/4 ton status Premium Member GMOTM Winner

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    Re: Extended shackle with the 57\" swap good or bad?

    I'm gonna jump into the middle of this cause this is gonne be my next mod. On the echobit site on teh write up it looks like you moved the perches back on the frame but on the shakle flip add at the bottom it looks like stock location on frame with just a longer shakle. Which way is better/ most benificial?
     
  7. BorregoK5

    BorregoK5 1/2 ton status

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    Re: Extended shackle with the 57\" swap good or bad?

    Rene moved the mount and I added the bracket. The end result would be about the same, the only difference would be that the bracket can not provide a lift below 5" where moving the bracket could.
     
  8. zakk

    zakk 1/2 ton status

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    Re: Extended shackle with the 57\" swap good or bad?

    when i read rene's post, he got 4" of lift moving the shackle.

    I have a 2.5" ORD flip kit, so if i move the shackle back i will lose lift? I would like to get 6.5" - 7" of lift so the rear is level....
     
  9. MNorby

    MNorby 3/4 ton status Premium Member GMOTM Winner

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    Re: Extended shackle with the 57\" swap good or bad?

    I plan on 6" +/- and may use a zero rate. It would be nice to not have to move the shakle mount back and just build longer shakles. Would that work ok and provide a good amount of movements to flex?
     
  10. BorregoK5

    BorregoK5 1/2 ton status

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    Re: Extended shackle with the 57\" swap good or bad?

    Rene kept the stock hanger but cut out the bottom and braced the top for a flip, the equivilent to the 4" ORD flip. The slightly longer shackle helps to provide the range of motion and a little lift (about 1" at most). Moving the mount forward and angling the shackle will reduce lift by a little.
     
  11. MNorby

    MNorby 3/4 ton status Premium Member GMOTM Winner

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    Re: Extended shackle with the 57\" swap good or bad?

    I plan on getting the echobit shakle slip and revers them so the are offset backward. Would I still need to mvoe the hangers back and how far do you reckon fo 6" roughly?
     
  12. BorregoK5

    BorregoK5 1/2 ton status

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    Re: Extended shackle with the 57\" swap good or bad?

    With the shackle brackets, no hanger relocation is needed, just longer shackles. I run this setup on my truck and net just under 6" of lift. There are a bunch of ways to top off that last half inch (shackle length, zero rate, angle shims, etc...).
     
  13. MNorby

    MNorby 3/4 ton status Premium Member GMOTM Winner

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    Re: Extended shackle with the 57\" swap good or bad?

    right on. I think that is the path I'm gonna go with then. Do you build the longer shakles or can you buy them somehwere at a certain length?
     
  14. BorregoK5

    BorregoK5 1/2 ton status

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    Re: Extended shackle with the 57\" swap good or bad?

    I can build the shackles too, finally got an in with the poly manufacturer so the whole deal stays affordable.
     
  15. MNorby

    MNorby 3/4 ton status Premium Member GMOTM Winner

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    Re: Extended shackle with the 57\" swap good or bad?

    how much for the extended shakles?
    Made a package deal with the shakle flips too?
     
  16. BorregoK5

    BorregoK5 1/2 ton status

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    Re: Extended shackle with the 57\" swap good or bad?

    The 57" conversion package is $125 with the brackets and greasable 6" shackles. All that remains is for you to find a set of 57's and redrill the pack. The rest bolts up.
     
  17. MNorby

    MNorby 3/4 ton status Premium Member GMOTM Winner

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    Re: Extended shackle with the 57\" swap good or bad?

    right on! Hopefully finish the 60 next month and maybe can order that in November. Thanks for all the input.
     
  18. BorregoK5

    BorregoK5 1/2 ton status

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    Re: Extended shackle with the 57\" swap good or bad?

    Yeah, get that 60 under there befoe you break something!
     
  19. MNorby

    MNorby 3/4 ton status Premium Member GMOTM Winner

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    Re: Extended shackle with the 57\" swap good or bad?

    Too late /forums/images/icons/grin.gif
    Right now my pass side stub shaft looks like overheated spagetti O's. At least one good thing about the older D44 are the rotors are good donors for rear disks baby!. Soon as teh 60 is in I am doing the 57"s /forums/images/icons/cool.gif
     
  20. BadDog

    BadDog SOL Staff Member Super Moderator Author

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    Re: Extended shackle with the 57\" swap good or bad?

    I think the changes due to longer shackles mj was talking about have to do with the arc described by the shackles as the spring flexes. This really doesn’t pertain at all to lift. Lift achieved through shackle length changes will often have adverse effects on suspension geometry, pinion angles, and (in the front) castor. Admittedly these effects will probably be minimal for most shackles of reasonable length and they can generally be corrected. Anyway, a relatively flatter arc keeps the spring rates from changing as dramatically due to changes in leverage and the effects of jacking/dropping. The ideal would probably be a slide like I saw in a suspension drawing. Basically the shackle was replaced with a slide that allowed the spring to compress (extend) and bow (contract) as needed.
     

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