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Technical Rear ladder bars

Discussion in 'Traditional Hot Rods' started by sdluck, Nov 27, 2018.

  1. sdluck
    Joined: Sep 19, 2006
    Posts: 2,038

    sdluck
    Member

    I am installing rear ladder bars on my Model A frame,do you guys install them so they are level to the front to back when they are at ride height,they are pete and jakes. Thanks. DDDenny please chime in.It is a model A roadster, frankland quickchange,SBC ,t 10 4 speed.
     
    Last edited: Nov 27, 2018
  2. DDDenny
    Joined: Feb 6, 2015
    Posts: 11,351

    DDDenny
    Member
    from oregon

    Hey SD
    And not just any sbc either!
     
  3. gimpyshotrods
    Joined: May 20, 2009
    Posts: 15,888

    gimpyshotrods
    Member

    For a fairly neutral street ride, make the lower bar level at ride height.

    You're not on a drag strip, or a road race course. Level is good.
     
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  4. mgtstumpy
    Joined: Jul 20, 2006
    Posts: 7,200

    mgtstumpy
    Member

    As Gimpy states, the ladder bars need to point up or be horizontal to be geometrically correct and give you anti-squat with the correct amount of pinion angle at ride height. Pointing them down will cause the car to squat under load which will in turn can cause the rear tyres to easily unload. The pinion will point down. The front pivot points need to correspond horizontally with centreline of housing at ride height.
    With anti-squat built in and bars pointing up at the front up, the wheels have a tendency to turn the axle in the opposite direction. This motion causes the bars to push the car up.
    With them pointing down the opposite occurs and the rear drops.
    Race cars can have 1-2 degree down angle
    [​IMG]
     
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  5. sdluck
    Joined: Sep 19, 2006
    Posts: 2,038

    sdluck
    Member

    Lower bar not upper?,what happens with upper bar level.This is a street car but it does have a aluminum SBC 427.
     
  6. sdluck
    Joined: Sep 19, 2006
    Posts: 2,038

    sdluck
    Member

    Are you talking the top bars need to point do,how much
     
  7. mgtstumpy
    Joined: Jul 20, 2006
    Posts: 7,200

    mgtstumpy
    Member

    The front pivot points need to correspond horizontally with centreline of housing at ride height so the top bar, if installed similar to above, will be horizontal (Parallel) to ground, lower bar will point up as it mounts lower. They need to taper in at the front pivot point. This is a 32 setup, those more experienced than me will chime in with more specifics.
    http://www.srbymichael.com/index.cfm?ptype=results&category_id=931&mode=cat&start=49
    https://www.hotrod.com/articles/install-ladder-bars-ford-9-inch/
    upload_2018-11-28_16-19-56.png
    upload_2018-11-28_16-17-44.png
     
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  8. Kerrynzl
    Joined: Jun 20, 2010
    Posts: 2,284

    Kerrynzl
    Member

    The front pivot point needs to be slightly lower than the axle centreline on a street driven vehicle.
    This does induce a slightly more amount of squat [which springs overcome]
    But the advantage is a more neutral ride because of roll understeer.
     
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  9. gimpyshotrods
    Joined: May 20, 2009
    Posts: 15,888

    gimpyshotrods
    Member

    This.
     
  10. sdluck
    Joined: Sep 19, 2006
    Posts: 2,038

    sdluck
    Member

    Thank you all
     
    Brian Eddison likes this.
  11. DDDenny
    Joined: Feb 6, 2015
    Posts: 11,351

    DDDenny
    Member
    from oregon

    Now, about that engine?
     
  12. sdluck
    Joined: Sep 19, 2006
    Posts: 2,038

    sdluck
    Member

    It is a SBC rodeck 427 aluminum block,brodix heads,roller cam.It has a 4 barrel 3310 on it now,later 2 1/16 hilborns mech injection
     
  13. These at P&J ladder bars on my '32 pickup, hope this helps. HRP

    upload_2018-11-30_11-44-44.jpeg

    upload_2018-11-30_11-45-11.jpeg
     
  14. 4ever18
    Joined: Nov 1, 2007
    Posts: 454

    4ever18
    Member

    24E1B445-7170-402A-8437-CBE79318D85E.jpeg 34E95550-4825-4EFC-BBF1-2A5BF8AEA1AF.jpeg FF33C8A7-7E00-49A9-BD49-4EF47C18D48F.png 5CBBD359-3F38-41D4-A302-C5233FD8AE04.jpeg 24E1B445-7170-402A-8437-CBE79318D85E.jpeg 34E95550-4825-4EFC-BBF1-2A5BF8AEA1AF.jpeg FF33C8A7-7E00-49A9-BD49-4EF47C18D48F.png 5CBBD359-3F38-41D4-A302-C5233FD8AE04.jpeg Here’s my old Model A, with Pete & Jake rear ladder bars.
     
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  15. gimpyshotrods
    Joined: May 20, 2009
    Posts: 15,888

    gimpyshotrods
    Member

  16. sdluck
    Joined: Sep 19, 2006
    Posts: 2,038

    sdluck
    Member

    front is 7 and 3/4 inches I believe
     
  17. gimpyshotrods
    Joined: May 20, 2009
    Posts: 15,888

    gimpyshotrods
    Member

    Not you, the guy with the photos. Those ladder bars look parallel.
     
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  18. 4ever18
    Joined: Nov 1, 2007
    Posts: 454

    4ever18
    Member

    03A710B0-F554-4B52-AFBC-21F0E0E4396D.jpeg
    The ladder bar kit comes with the front crossmember, with those attachment brackets already welded in place. I no longer own the Model A, but I checked my ‘34 and here’s what I have. My ladder bars are 43” long, including the rear clevice. If your bars are this same length, the setup dimensions will be the same as the ‘34 Ford. The bars mount to the front crossmember, 6” apart. They mount to the rearend 31 1/4” apart (if my eyesight is correctly reading that fraction).
     
  19. 4ever18
    Joined: Nov 1, 2007
    Posts: 454

    4ever18
    Member

    They are not parallel. I used the Pete & Jakes crossmember, which determines the angle.
     
  20. 4ever18
    Joined: Nov 1, 2007
    Posts: 454

    4ever18
    Member

    Did you see my response to this question? It’s two notes, prior to this one.
     

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