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should I mount the 4" shackle flip backwards?

Discussion in 'OffRoad Design' started by harry, Feb 9, 2001.

  1. harry

    harry 1/2 ton status

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    should I mount the 4\" shackle flip backwards?

    I have the 4" shackle flip from ORD. I was wondering in if I should mount them backwards so I could have a longer spring in back. What would be the Pros/Cons and far as drive ability on and off the the highway?? I don't know if it makes a difference but I have a 69 K5 with a 14 bolt in the rear and a dana 60 in front.

    thanks, harry
     
  2. Stephen

    Stephen 1/2 ton status Moderator Vendor

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    Re: should I mount the 4\" shackle flip backwards?

    You could use that method to get longer springs in there, that's just what I did. I built a 55" main leaf and turned the brackets around on the frame. I kept the center pins centered and thus moved the axle back about 1.5". Really, that's the main reason for the extra length in my case. I wanted to help out the tire clearance to the front of the opening (I trimmed a lot in the back of the opening) and it helps the departure angle.
    If you're looking into more flex from a longer custom spring, you should just go ahead and stretch them as long as possible. The IFS trucks use a 63" rear spring, that would be a good length to aim for. You'll have to move the mounts, so it won't be as easy as just flipping the brackets, but it would probably be worth it since custom springs are expensive and it's best to buy them once.

    Making the world better, one truck at a time.
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  3. Re: should I mount the 4\" shackle flip backwards?

    I have swapped springs on my blazer, front springs are now 52" rear springs w/custum work done needed to fit, rear springs are 66" springs from a 97'ish 1/2 chev p.u., spring mounts have been moved as needed to fit, front axle was moved 1.5" to the front, rear axle was moved 1.5" back,
    this give me aprox 4" lift w/soft springs, and will clear 36"
    at full stuff/sterring locked. at least i think it will when flexed
    out in the garage, project is still in process.
    p.s. ORD ROCKS!
     
  4. Ryan Melton

    Ryan Melton Registered Member

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    Re: should I mount the 4" shackle flip backwards?

    Stephen,

    Do 63" IFS springs provide the same amount of height as a factory Chevy 52" rear spring? How much of an increase in articulation could be expected from going from a factory 52" or 56" spring to a fact 63" spring. How much additional flex would Alcan 63" springs provide over your 55" springs. How much additional flex would running 52" or 54" springs in the front yield?

    Thanks for your help.

    Ryan
     
  5. Executioner

    Executioner 1/2 ton status

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    Re: should I mount the 4\" shackle flip backwards?

    HOE DO YOU MEASURE FLEX ?
     
  6. Stephen

    Stephen 1/2 ton status Moderator Vendor

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    Re: should I mount the 4\" shackle flip backwards?

    There are several different ways to measure the axle travel, one is just vertical travel, the other is axle articulation. The easiest way to measure articulation is to jsut meaure tire to fender on each side and subtract them.

    As for the spring length, the longer the better. But, practically speaking, my fronts are 48" long, in the stock mounting points, and I would go to 49" if I did it again. They use up all of a 12" shock in articulation, and maybe a bit more if I pushed it, so I don't think the extra couple of inches to go to 52"s would be worth it. My rear flex depends a lot on the load, when it's empty, it doesn't move near as much as when it's loaded, but I wanted to be able to carry some gas and gear in it so I designed the springs a bit stiffer. If you're going to do much more than just move the rear mount, you should go all the way to the 63" rear. I don't know if the IFS truck lift spring would give you the same lift as a 73-87 lift spring. Haven't played with that.
    The length helps in a couple of ways, one is the lateral twist in the spring, the longer the material, the more it can twist. The other is the motion of the material itself, the longer it is the more it can droop and compress at the same stress levels.
    Hope this helps

    Making the world better, one truck at a time.
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  7. Re: should I mount the 4\" shackle flip backwards?

    The 52" front springs have had leafs added and removed to get them set up right. It ended up to be about 4" of lift. The front mounts were moved forward, rear shackle to frame mountis in the stock postion, the shackle is about 1" longer and laid way-back. All this was done to move the front axle 1"
    forward. At first I tried to move 4"lift 48" long springs forward but that put the shackle angle all wrong. So after a few other ideas (and six-packs) I ended up w/the 52" springs.
    The 63" rear springs are about the same as 52" springs, just longer. Lift depends on the mounts/hangers/blocks/etc.
    1- Will the shackle flip reduce load carring? I plan to tow the rest of my junk around with this Blazer.
    2- What do you (anyone) know about Instant Center. (I.C. = driveing force applied threw links/leafs vs. Center of Gravity)
    and how does it applie to wheeling? Watch a lifted T.J. to see what I'm taliking about.
    3- Still have chrom-moly shafts for 44s?, If so save me a set.
    4- What do you think of the reliability of a reverse 60 in the rear? (9.75" ring gear driven on the coast side)
    WHEW! Thanks everybody/SSteve
    ORD ROCKS!
     
  8. Stephen

    Stephen 1/2 ton status Moderator Vendor

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    Re: should I mount the 4\" shackle flip backwards?

    I think you're asking for a book here with some of this stuff!

    Load carrying loss with the flip depends on how your shackle angle ends up. Our kits are set up to where you don't lose anything with it if the spring doesn't invert too far. If you've pulled the overload leaf, you will lose load carrying capability, duh :-) and it will also let the pack reverse arch to where you could have some durability issues. If the shackle angle at full compression isn't kicked back too far, you should be ok.

    There's been a lot of work going on with rear link geometry lately, that's why the long arm TJ kits exist. I've been doing some polling of experienced TJ guys, and what I've heard is that the rubicon kit is really good, the Warn XCL is close to it, and the stock mounting point suspensions really suck. It seems like anti squat ratios in the neighborhood of 50% are where they're ending up. It's really important for an offroad rig, if you stand it on it's ass and it tries to pick up under torque, you're going over. Biggest thing is making it predictable I think. If it reacts the same in most situations, it's going to be easy to drive, and that's a function of the length of the arms.

    We're out of the chromos right now, for d44 anyway, we have a set of 10 bolts in stock. We're going to try to keep carrying them.

    I think with a reverse 60, you'll have more problems with the ring gear than with axle shafts. If you're running it with a 1/2t front axle, you probably won't have any worries, you'll pop a joint before you can put that much torque on the rear. Dynatrac probably has some input on that question, since that's a cornerstone of their biz.


    Making the world better, one truck at a time.
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