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56" rear springs?

Discussion in 'The Garage' started by lifethroughdeath, Apr 14, 2004.

  1. lifethroughdeath

    lifethroughdeath 1/2 ton status

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    56\" rear springs?

    does anyone know what specific vehicles the 56" springs came in, and how many leaves are in the pack? i was under the assumption that they were 5 leafs in the pack, but i recently asked a guy who sells leafsprings and he couldn't figure it out /forums/images/graemlins/dunno.gif when i install my flip i figure i might as well swap my 52's for 56's. What is the ideal 56" leaf spring as far as # of leaves go for flex? Thanks

    Nate /forums/images/graemlins/k5.gif
     
  2. Muddytazz

    Muddytazz 1 ton status

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    Re: 56\" rear springs?

    The obvious is the less leafs you have the more flexy it will be.

    56" springs came in 78 or 79 and up 3/4ton rigs.


    As for the spring count. My dads 3/4ton stock 56" springs have 11 leafs AND an 1" thick overload leaf /forums/images/graemlins/yikes.gif
     
  3. K5BLT4FUN

    K5BLT4FUN 1/2 ton status Premium Member

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    Re: 56\" rear springs?

    The 56" rear spring packs were also available in 1/2 Suburbans from 81-91. I know this because I had a 91 with them and a friends 85 had them as well. You will just have to look. Skyjacker sells the 56" rear spring in a 4" or 6" lift pack I believe. I had a set of 6" Skyjacker 56" rears until recently. Check with Mudzer he has them now and could probably tell you the leaf count.
     
  4. BadDog

    BadDog SOL Staff Member Super Moderator Author

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    Re: 56\" rear springs?

    56's were found in mid/late 70s up C/K models for "heavy half" tons, most 3/4 tons, and all 1 tons up until the end of the R/V series in 91. The "new" C/K series introduced in 87 used totally different springs.
     
  5. lifethroughdeath

    lifethroughdeath 1/2 ton status

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    Re: 56\" rear springs?

    [ QUOTE ]
    The obvious is the less leafs you have the more flexy it will be.
    As for the spring count. My dads 3/4ton stock 56" springs have 11 leafs AND an 1" thick overload leaf /forums/images/graemlins/yikes.gif

    [/ QUOTE ]

    So then when people are swapping these in they're removing a lot of leaves i assume. I remember sidslc swapped 56" springs in the rear and he had only 5 leaves in the pack. /forums/images/graemlins/dunno.gif

    Nate /forums/images/graemlins/k5.gif
     
  6. BadDog

    BadDog SOL Staff Member Super Moderator Author

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    Re: 56\" rear springs?

    We removed most of the leafs from the K30 56" rears we put on my son's K5. It’s got 4 or 5 plus the overload flipped. Nice thing is the number of leafs makes them very "tunable".
     
  7. sidslc

    sidslc Registered Member

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    Re: 56\" rear springs?

    Funny I just finished instaling a set on my blazer. The best ones that I found as far as the spring rate was from tuff country. the reason I went to the 56' springs was to turn them around backwards and strech the w/b out 5'. there was lots of benifits and only one drawback. the benifits are driveline angle, departure angle, and more unsprung weight at the rear. the only thing that sufferd is the break over angle. go to the link by my sig and look.

    later
     
  8. BadDog

    BadDog SOL Staff Member Super Moderator Author

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    Re: 56\" rear springs?

    With asymmetric springs turned backwards you also have to deal with pinion angle problems. It wants to turn down toward the ground on droop and also on flex since most of us have more down travel than up. Then there are more spring wrap issues as well when a positive arched spring has a longer front than the rear. I know you've got a wrap bar to take care of that as do I with my reversed 57" F150s. But then, because the spring and wrap bar are in contention, you get some bind from the two fighting each other. Just wanted to let others know that it's not completely straight forward to flip asymmetric springs.
     
  9. sidslc

    sidslc Registered Member

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    Re: 56\" rear springs?

    ya thats true I did rotate the pinion up and made new spring purches to compinsate for that. but with the new ladder bar that I made I got rid of almost all the bind and freed up the rear end a lot compaired to the first ladder bar that I made
     
  10. lifethroughdeath

    lifethroughdeath 1/2 ton status

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    Re: 56\" rear springs?

    [ QUOTE ]
    With asymmetric springs turned backwards you also have to deal with pinion angle problems. It wants to turn down toward the ground on droop and also on flex since most of us have more down travel than up.

    [/ QUOTE ]

    So if i installed 56" springs backwards to increase wheelbase and departure angle, etc... if i'm running a shackle flip with an extended shackle (which would point the pinion up) that should help with the pinion angle right.? Bring it back to where i want it.

    Nate /forums/images/graemlins/k5.gif
     
  11. BadDog

    BadDog SOL Staff Member Super Moderator Author

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    Re: 56\" rear springs?

    Not really. At static height you'll be pointed at the case like for a CV. Then on droop or significant articulation, the pinion will be rotated toward the ground because the spring is bowing into a more pronounced arch. Normally, the axle will be on the forward half of this arch, so the pinion starts to turn up as the arch increases. This actually helps at low speeds due to the small decrease in shaft angle required for a given droop and less angle on the lower joint which means more over all droop before binding.. When the springs are reversed putting the short side in the back, the axle is on the back part of the arch, and all this is reversed. The more severe the arch, the more the axle is going to rotate the pinion into the ground, making shaft and joint angles more severe rather than better. Stopping this tendency to point the pinion into the ground (by using an anti-wrap bar) is restricting the spring from moving the way it wants to move, and so by definition, you have introduced "bind". I counter this in my suspension (to a large extent) by running the Springer/AK57 drop arms on the back (short side) to effectively make it behave as if it were a symmetric spring by letting the lower eye drop when the anti-wrap stops the axle from rotating. So, instead of forcefully deforming the spring and introducing bind, the spring follows a more normal deformation and eliminates most of the bind without allowing the negative effects.
     
  12. lifethroughdeath

    lifethroughdeath 1/2 ton status

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    Re: 56\" rear springs?

    baddog thanks a lot, it all makes sense now /forums/images/graemlins/waytogo.gif

    Nate /forums/images/graemlins/k5.gif
     

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