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Shackle Flip on a 71 Suburban

Discussion in 'OffRoad Design' started by 72burb, Nov 27, 2006.

  1. 72burb

    72burb Registered Member

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    I want to do a 6" lift on my 71 Suburban. I was thinking of 6" springs in the front, and 4" shackle flip with 2" springs in the rear.
    Will the shackle flip push the rear axle forward? What will correct that?
    Would I just be better off with 6" springs in the rear?
     
  2. PsRumors

    PsRumors 1/2 ton status

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    It might push it forward some. The biggest problem you will have is pinion angle. You will probably need to shim the axle to bring the pinion down some.

    If you use the full springs you shouldn't have any problems.
     
  3. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    When i did my ORD shackle flip it moved the axle forward 1". The cure would be a 1" zero rate with an offset mounting hole so you can bring the axle back that 1" or even better 1.5".
     
  4. PsRumors

    PsRumors 1/2 ton status

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    Did you use the 4"? If so then I should only see 1/2" movement with the 2 1/2" flip.
     
  5. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    Yes, i used the 4" ORD flip.
     
  6. 72burb

    72burb Registered Member

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    4x4 High & psrumors:

    Thanks for the feedback. Looks like the 1" zero rate is the way to go. The ride with the shackle flip has got to be better than 6" springs.

    72 Burb
     
  7. Stephen

    Stephen 1/2 ton status Moderator Vendor

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    The forward movement of the axle with a flip depends on a LOT of factors. The biggest is the arch in the springs and I think the 2nd biggest is just how it's measured. With a stock spring, the flip moves the axle about 1/4" which is basically imperceptible without a tape measure. With more arch that can be a bigger number since the spring isn't flat.
    Part of the problem is that the tire starts off closer to the front of the wheel well on these trucks (early and later model) so we really need to move it back to start with.

    With the early trucks, you typically have to run a spring with more arch than a '73-up so the axle will normally move forward more. There are some games you can play to fix it though, like the Zero rates mentioned earlier and another one is flipping the springs around so that the long part is to the front. Not all lift springs have an offset pin but those that do make it easy to move the axle back a little.
    Also keep in mind that if there is some arch in the springs, the axle will move back when it compresses so if it's sits at the front of the opening a bit, it could move to the right place in bump travel.
    Hope this helps
     
  8. jughead

    jughead Registered Member

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    I have run into this exact problem of the rear being push too far forward with the 4 inch shackle flip. I used lift that the PO was going to use (6 inch arched springs). So total lift is 10 inches in the rear. Up front I went with the 6 inch springs and a 1 inch zero rate. I already am higher in the reaer so to use your idea of adding a zero rate in the rear I will be way too high. I a 72 K5 which normally are lower in the ass end that is why I went the route I did. I am not happy with the ride and I feel it is due to the rear being pushed forward and not getting the right action from the springs.
     
  9. jughead

    jughead Registered Member

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    Also I had a spring shop suggest to redrill the spring pack and move the rear back. Would this also change the action the spring should normally have since it is now not on center? I am looking for a fix without hurting my wallet too much.
     
  10. 55Willy

    55Willy 3/4 ton status

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    what shackles you running and whats your angle of shackle?
     
  11. jughead

    jughead Registered Member

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    4 inch ORD.
     
  12. 55Willy

    55Willy 3/4 ton status

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    thats the flip, but what length shackle stock? longer? and at what angle?
    my buddy has a 4" ord 1st gen flip with 8" springs and a lifted shackle and the shackle is at like a 10-15* angle and it actually rides and flexes great for such a lifted spring.
    in my opinion a stock shackle sucks when doing a flip they don't allow the springs to move right.
     
  13. jughead

    jughead Registered Member

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    I get what you are saying....I need to post some pics of it....A longer shackle in the back does not fix the problem of the rear being too far forward though. I was thinking of eliminating the rear shackle and adding a 2 inch block but I am sure there is a need for a shackle so I will probably have to get new springs altogether.
     
  14. 55Willy

    55Willy 3/4 ton status

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    did you flip the ORD brackets around so the shackle hole is farther forward?
     
  15. jughead

    jughead Registered Member

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    No they are not flipped around....I had thought of that also but was told that if i flip them around I could colapse the whole set up. I am going to post pics of it tomorrow for sure I just have not had the time and weather issues.
     
  16. jughead

    jughead Registered Member

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  17. jughead

    jughead Registered Member

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  18. bp71k5

    bp71k5 3/4 ton status Premium Member

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    That's pretty much what mine looks like. Would a longer shackle give a better angle? Mine's not very flexy in the back.
     
  19. 55Willy

    55Willy 3/4 ton status

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    what springs are those? i would measure both front and rear eyey to center pin. On Arturo's we turned the springs around even though a 52" spring claims a centered pin it wasn't so it slide it back an inch. looks like you'd need atleast a 1.5" off set zero rate if you can't turn them around. I don't see how the bracket would collapse, never heard of one doing it and I have seen 3 rigs personaly with em flipped.
     
  20. jughead

    jughead Registered Member

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    I wrote about this awhile ago when I first put it in and asked the question about using a longer shackle and was told it would collapse. Never understood how to measure these leafsprings. Is it total length along the spring? Or from straight line from eyehole to eyehole? I do remember it being dead in the middle though. I need to crawl under truck to remeasure cause know I am second guessing myself.
    I already have a zero rate up front. If I add one to the rear I will be adding another inch when it is already an inch and a half higher than the front now. I was wondering if I were able to add an add-a-leaf on top of the zero rate up front. First would it be safe? And second would it further stiffen the ride? I may just opt for a new set of springs in the rear and level the whole truck out. I am still trying to figure out how to post pics without the link. Its driving me nuts.
     

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