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Technical Shortest front parallel leaf springs

Discussion in 'The Hokey Ass Message Board' started by h2omonkey, Aug 28, 2016.

  1. h2omonkey
    Joined: Dec 8, 2008
    Posts: 165

    h2omonkey
    Member
    from vegas

    What is the shortest front parallel springs anyone has run? Speedway has 26 1/8 for novas, only ones shorter I'm finding are for trailers that have too high a spring rate. Looking to put a straight axle in an ot car (52 jeep cj) and want to relocate the axle forward from stock position but still under frame and not way out front. Spring will need to be roughly 22 inches if axle is centered. Want to do parallel springs because this will be the easiest to set up. Haven't decided on motor yet, I know the final weight will effect what spring rate to use. Is this possible or am I going to have to do a single suicide sping/axle set up/ Thanks for any opinions and ideas.
     
  2. seb fontana
    Joined: Sep 1, 2005
    Posts: 6,888

    seb fontana
    Member
    from ct

    IMO go with a single cross spring would be the best..Many choices of mounting the spring [above, in front, behind ] the axle and a multitude of spring choices...Radius rods not difficult to mount and steering poses no different issues..Again, IMO..
     
  3. henry's57bbwagon
    Joined: Sep 12, 2008
    Posts: 677

    henry's57bbwagon
    Member

    Any spring shop can make any length you want.
     
  4. seb fontana
    Joined: Sep 1, 2005
    Posts: 6,888

    seb fontana
    Member
    from ct

    I can only imagine what a 22" long spring would be like; very little travel possible..
     
    Hnstray likes this.

  5. RichFox
    Joined: Dec 3, 2006
    Posts: 10,004

    RichFox
    ALLIANCE MEMBER

    When i wanted a short spring I went to a boat trailer store. ordered what i wanted. had I thought it was to stiff, I could have removed a few leaves, I guess.
     
    LOU WELLS likes this.
  6. Mr48chev
    Joined: Dec 28, 2007
    Posts: 28,552

    Mr48chev
    ALLIANCE MEMBER

  7. Phil1934
    Joined: Jun 24, 2001
    Posts: 2,717

    Phil1934
    Member

  8. Joe H
    Joined: Feb 10, 2008
    Posts: 1,007

    Joe H
    Member

    I have a pretty new set of '37 Chevrolet 1/2 ton springs with four leafs per pack, they measure 26 1/2" eye to eye. Send me a note if interested. I measured them around 325 lb spring rate per side. They held up my truck front just fine with 250 inline six. Could be a little heavy for your jeep.

    Joe
     
  9. Hooley
    Joined: Mar 13, 2004
    Posts: 108

    Hooley
    Member

    I run small trailer springs on the Henry J. We remove a leaf from the right side and put it in the left side. It has ran for several years now. I hit the guard rail last fall and then replaced them with the same ones. It worked for me.
     
  10. Phil1934
    Joined: Jun 24, 2001
    Posts: 2,717

    Phil1934
    Member

    Hooley, what was the load rating on yours?
     
  11. Ned Ludd
    Joined: May 15, 2009
    Posts: 4,211

    Ned Ludd
    Member

    Keep in mind load capacity isn't the same as spring rate. Trailer springs are advertised by load capacity, not spring rate. Drag-oriented cars generally want lower spring rates and lots of travel, to let the nose rise on launch but keep the front wheels on the ground.

    Try this spring rate calculator.

    A transverse leaf set-up with a Panhard bar will allow cross-steering with correct geometry i.e. no bump steer. But how about three-quarter elliptics? See (B) below:
    [​IMG]
     
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  12. Phil1934
    Joined: Jun 24, 2001
    Posts: 2,717

    Phil1934
    Member

    Steering is a future question. The side steer box needs to be on the fixed side of the spring. But I wonder if cowl steering is used how much bump steer will you really get on a low crown spring. I had looked at this calculator http://www.suspensionmaxx.com/tech-support/leaf-spring-calculator/
    The 750# spring was 570#/", the 500# was 290#/" and the 300# was 200#/". Speedway sells 400#/" springs.
     
    Last edited: Aug 29, 2016
  13. aaggie
    Joined: Nov 21, 2009
    Posts: 2,531

    aaggie
    ALLIANCE MEMBER

    At least you are doing it right by thinking it through before building. Most people just put something together that looks right then spends a lot of time and money trying to fix problems. Good luck with the project.
     
    AHotRod likes this.
  14. Barn Find
    Joined: Feb 2, 2013
    Posts: 2,317

    Barn Find
    Member
    from Missouri

    Why don't you extend the front frame rails? I've seen this done on many old CJs to accommodate longer springs, and/or move the axle forward for weight distribution or steering geometry. I think they look good when done right.

    I am working on a WWII Dodge WC59, which is built a lot like a Jeep-only bigger. I wanted longer springs, because the originals were so rough riding. I also stretched the frame 9" to accommodate a straight-eight, and the longer springs and moving the shackle to the back helped make up some of the stretch. On the military Dodges, those with winches had longer frame rails. I used winch frame rails to get the length I needed to mount longer front springs farther forward.

    On the civilian Dodge Power Wagons, they bolted an extension onto the frame instead of having an entirely different frame when a winch was added. There might be a similar trick you could use on the Jeep.
    [​IMG]
     
  15. Rusty O'Toole
    Joined: Sep 17, 2006
    Posts: 9,479

    Rusty O'Toole
    Member

    You can relocate the axle using stock length springs with the mounting point farther forward. Most cars with leaf springs at the back use this trick. The short stiff front part controls spring windup while the long flexible back part allows more suspension travel and a decent ride.

    Short springs limit suspension travel and result in a rough ride.

    There should be a spring shop in your area that can make any kind of springs you want. Since they work with leaf springs every day, why not ask them what kind of springs will work best? New springs for your Jeep, around $100 - $150 apiece.
     
  16. Hooley
    Joined: Mar 13, 2004
    Posts: 108

    Hooley
    Member

    Phill934, I am not sure what the spring rate is. The whole car weighs 2,800 lbs. They were for a small trailer. I chose them more on length than weight. I could add leaves if needed. Good luck with what with your project and make it safe as you can.
     

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