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quarter elliptic spring front end

Discussion in 'The Hokey Ass Message Board' started by fattrodder, Jan 29, 2008.

  1. FiddyFour
    Joined: Dec 31, 2004
    Posts: 9,024

    FiddyFour
    Member

    jj mack, take another look... his setup has top mounted bars in addition to the bottom mounted quarter elipticals. think hairpins. his caster angle will remain the same during suspension travel, just as unkl ian mentioned in his four-bar analogy
     
  2. jj mack
    Joined: Mar 22, 2007
    Posts: 735

    jj mack
    Member

    HUH?

    Look here.

    http://www.milleroffy.com/miller_122_frontdrive_rear_web.jpg

    Spring on top....spring on bottom...both will more the same like a 4 bar. Change one from a spring to a bar..it wont work.

    The only point to this is....Lakemods setup will not work properly unless he adds a shackle or something else to control the axle angle.
     
  3. Easy enough to test.
    Bolt it together with just the main leaf,and see what happens.
    ----
    Shackles don't "control the axle angle".
    They pivot on both ends.
    Kind hard to control anything with 3 pivot points per side.

    Shackles would make the problem worse,instead of better.
     
  4. 067chevy
    Joined: Sep 18, 2005
    Posts: 2,073

    067chevy
    Member

    I agree
     
  5. jj mack
    Joined: Mar 22, 2007
    Posts: 735

    jj mack
    Member

    I buy that....

    I think Turbo26T's pic is the correct way to do it...If he plans to use the the lower bar also.

    I dont think that using a spring to replace a bar of a 4 link set up is a good thing.
     
  6. 067chevy
    Joined: Sep 18, 2005
    Posts: 2,073

    067chevy
    Member

    you don't need 2 bars if you don't use a shackle. your spring is one bar. but I think you want your spring and bar parallel
     
  7. Mr48chev
    Joined: Dec 28, 2007
    Posts: 33,861

    Mr48chev
    ALLIANCE MEMBER

    Here are a few photos of a T in WA state.
    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]

    I don't know anything about it except it has a lot of nifty ideas in it and I like it.
     
  8. DrJ
    Joined: Mar 3, 2001
    Posts: 9,419

    DrJ
    Member

    I can't think of any car manufacturer that mounted a spring with just the through bolt(s).
    They always use a U bolt type fastener that surrounds the spring or a rolled end on the spring that surrounds the fastener in a way that allows the movements that are going to happen without placing the type of forces on the fastener that will loosen, bend or break it.
    I think the flexing and twisting of the spring while moving down the road is going to either loosen and/or break those bolts.
    I think you NEED to put U bolts on to to encapsulate the spring and hold it against the frame.

    I may be wrong, but if I'm right you truely have a suicide front end.

    At least drill and safety wire them.
     
  9. lakesmod
    Joined: May 27, 2002
    Posts: 458

    lakesmod
    Member

    Zipper Motors use two bolts to hold the spring,no u bolts.

    www.zippermotors.com

    The guy that has the modified I built(the one in the spring pitcures) drove it from Hot Rod-A-Rama(Tacoma) to Spokane and said it handles like a go-cart and rides great.The last time I talked to him he had over 3K miles on it.

    Fred



    www.zippermotors.com
     
  10. pikesan99
    Joined: Aug 13, 2002
    Posts: 370

    pikesan99
    Member

    Here are the pics of what I did: http://www.myrideisme.com/Garage/pikesan/10/47/
    I have the springs mounted inside the 2x3 frame with 2 thru bolts that are actually part of the headlight stand/shock mount. 3 years on the road and no problems. I check them very regularly (thanks Dr. J) and of course, I used Grade 8 with nylocks.
    Let me know if you want any other kind of pictures.
    pikesan
     
  11. jj mack
    Joined: Mar 22, 2007
    Posts: 735

    jj mack
    Member

    4 bars work because you have fixed attachment points and the bars are a fixed length....Springs are not a fixed length.

    As the spring flattens out...the distance from the mounting point to the eye lengthens. this will change the angle of the axle. The only way to prevent this is to add a shackle to compensate for the lengthening.

    At the same time you will also need to use something...wishbone, radius arm, haipin, etc to control the axle angle.

    The problem with lakemod's ...from My proscpective...is if he is using the pictured set up only....the angle will change.

    I hope he tries it out as I mentioned before. And would like to hear the result.
     
  12. If you use any 4 link with non parallel arms,or different lengths
    top and bottom,or both,you will get some angular change through travel.

    Just like on the back of many GM coil spring cars.

    The common street rod "triangulated 4 bar" typically uses
    different length arms top and bottom,mounted at different angles.

    Not a problem.
     
  13. And then what happens ?




    These cars are typically sprung stiff enough,
    that the suspension travel is minimal.
    Which makes any angular change small.
     
  14. jj mack
    Joined: Mar 22, 2007
    Posts: 735

    jj mack
    Member

    Bump steer. How much...I dont know.
     
  15. jj mack
    Joined: Mar 22, 2007
    Posts: 735

    jj mack
    Member

    Not the same analogy......
     
  16. jj mack
    Joined: Mar 22, 2007
    Posts: 735

    jj mack
    Member

    Bottom Line.

    I dont give a fuck how you build your car.

    I think Lakemod's will cause problems. But it is his and he can do what he wants. At least maybe he'll think about it and check it out to make sure.

    And I sure hope that if I post picks that someone thinks are fucked up some one says something about it. Isn't that why we post em?
     
  17. bobw
    Joined: Mar 24, 2006
    Posts: 2,376

    bobw
    Member

    The black '27 in the picture on page 1,(post #5) has a no-shackle arrangement, with the spring acting as one of the bars in the 4 bar set up. It's been on the road for 6 years with no problems and no bump steer. In a previous thread on this same subject, a number of people pointed out that some British sportscars (MG Midget, Healy Sprite?) used this arrangement in the rear.
     
  18. jj mack
    Joined: Mar 22, 2007
    Posts: 735

    jj mack
    Member

    Lets see some pics!!!
     
  19. sodas38
    Joined: Sep 17, 2004
    Posts: 2,410

    sodas38
    Member

    evil1 is working on a 30 Durant that used the Posie's set-up. It may help with ideas:

     
  20. sodas38
    Joined: Sep 17, 2004
    Posts: 2,410

    sodas38
    Member

    The set-up I built, I used 1-rear leaf spring off a 57 Chevy and cut it in half. Then I bought 2 sets of the front spring mounts from Speedway Motors, the kind that mounts to a 3"tube. Then I just sliced the curved part of at a right angle so it could be welded to the side of a frame rail. Then you just need the spring shackle mounts and the spring shackles.
     
  21. jj mack
    Joined: Mar 22, 2007
    Posts: 735

    jj mack
    Member


    Great looking setup.
     
  22. 067chevy
    Joined: Sep 18, 2005
    Posts: 2,073

    067chevy
    Member

    doesn't seem to be any shackles on the posie truck. I'm not saying there shouldn't be. I like my own design just fine but always looking new and better ways to build it
    [​IMG]
     
  23. jj mack
    Joined: Mar 22, 2007
    Posts: 735

    jj mack
    Member

  24. bobw
    Joined: Mar 24, 2006
    Posts: 2,376

    bobw
    Member

    [​IMG]
    J J, I don' have any pics of the '27 handy. But, I liked the set up so well that I build this shackless rear suspension for my International last winter. Drove it all summer.
     
  25. 067chevy
    Joined: Sep 18, 2005
    Posts: 2,073

    067chevy
    Member

  26. Dyce
    Joined: Sep 12, 2006
    Posts: 1,973

    Dyce
    Member

    It reminds me of a triangulated four link on a rear axle. Looks like it would work.
    [​IMG]
     
  27. bobw
    Joined: Mar 24, 2006
    Posts: 2,376

    bobw
    Member

    [​IMG]
    Side view of quarter elliptic without shackle.
     
  28. bobw
    Joined: Mar 24, 2006
    Posts: 2,376

    bobw
    Member

    [​IMG]
    See the parallel bar underneath.
     
  29. bobw
    Joined: Mar 24, 2006
    Posts: 2,376

    bobw
    Member

    [​IMG]
    A poor pic of the mount to the axle. Over 10,000 miles of trouble free, no bump steer driving.
     
  30. jjmack: That pic was made when I was in the mock-up stage and had a temp. link in place...heres a shot made a little further along in the build
    Stan
     

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