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Technical Rear 4 Link Setups

Discussion in 'The Hokey Ass Message Board' started by LUTHER99, Dec 7, 2021.

  1. LUTHER99
    Joined: Aug 11, 2011
    Posts: 40

    LUTHER99
    Member

    Looking for some ideas and pics on a rear 4 link suspension set up on a Model A frame , Thanks .
     
  2. 1934coupe
    Joined: Feb 22, 2007
    Posts: 5,051

    1934coupe
    Member

    I've built a few in my time and have gained some thoughts on the subject. On my MG I have a unequal length 4 bar. For my purpose it works great. On a Model A I would run the GM truck lower arms with upper arms running from the center outward. I just don't think that P&J's system looks that good. That is what I would do, it's just my opinion.

    Pat
     
  3. oj
    Joined: Jul 27, 2008
    Posts: 6,454

    oj
    Member

    On a typical A the 4 link is an unnecessary complication, the whole purpose of the Model A hot is simplicity. Stick to the tried and true suspension stuff and you'll be happier.
     
  4. lostone
    Joined: Oct 13, 2013
    Posts: 2,820

    lostone
    Member
    from kansas

    My 31 tudor
     

    Attached Files:

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  5. krylon32
    Joined: Jan 29, 2006
    Posts: 9,397

    krylon32
    ALLIANCE MEMBER
    from Nebraska
    1. Central Nebraska H.A.M.B.

    I've done countless customer A chassis and have good luck with Pete & Jake's Model A triangulated 4 bar set up with coilovers.
     
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  6. Hnstray
    Joined: Aug 23, 2009
    Posts: 12,355

    Hnstray
    ALLIANCE MEMBER
    from Quincy, IL

    Please define “GM truck lower arms”

    Ray
     
  7. AccurateMike
    Joined: Sep 14, 2020
    Posts: 631

    AccurateMike
    Member

    Ray, '60-'72 C10 2WD. Google "Truck Arm". Mike
     
  8. jaracer
    Joined: Oct 4, 2008
    Posts: 2,419

    jaracer
    Member

    This is a Heidt's triangulated 4 link. I'm pretty happy with it.

    IMG_1290.JPG
     
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  9. mgtstumpy
    Joined: Jul 20, 2006
    Posts: 9,214

    mgtstumpy
    Member

    What ever 4-bar you settle on, I'd suggest a stout 'K' member to minimise any torsional frame twisting.
     
  10. 1934coupe
    Joined: Feb 22, 2007
    Posts: 5,051

    1934coupe
    Member

    Ray what accurate mike said I couldn't think of a name only what they where on.

    Pat
     
  11. 52lomofo
    Joined: Jan 29, 2005
    Posts: 788

    52lomofo

    welder series and they are in Ontario
     
  12. Hnstray
    Joined: Aug 23, 2009
    Posts: 12,355

    Hnstray
    ALLIANCE MEMBER
    from Quincy, IL

    I know what the term generally describes, I even have them on hand for a project. However the reason I asked for a definition is because the “GM truck arms” are NOT used in a 4 bar configuration and the reference seemed out of place. They are used in pairs, one each, left and right, are rigidly u-bolted to the axle housing (no pivot point) so they do not require “upper arms” to control the axle housing …..as do actual 4 bar setups. They do require a Panhard bar to control axle housing lateral movement.

    Ray
     
    Last edited: Dec 8, 2021
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  13. AccurateMike
    Joined: Sep 14, 2020
    Posts: 631

    AccurateMike
    Member

    Ray, sorry I just saw
    I have no idea what the reference was. Mike
     
  14. grdra1
    Joined: May 20, 2013
    Posts: 526

    grdra1
    Member

    Jaracer, what angle are the top bars and length compared to the bottom bars on your chassis, thanks Glen
     
  15. Hnstray
    Joined: Aug 23, 2009
    Posts: 12,355

    Hnstray
    ALLIANCE MEMBER
    from Quincy, IL

    @AccurateMike Just for clarification, the reference was contained in post #3 (see above), which was ‘quoted’ in my post #7, to which you responded. Thank you for offering assistance….no harm, no foul.

    Ray

    Ray
     
  16. LUTHER99
    Joined: Aug 11, 2011
    Posts: 40

    LUTHER99
    Member

    Thanks for all the replies , lots of info , will ,post pics when l'm into it .
     
  17. dmar836
    Joined: Oct 23, 2018
    Posts: 357

    dmar836
    Member

    Im sure those who’ve contributed to this won’t care but are there pre-‘65 photos of 4- links?
    This is in the Traditional Hot Rod forum but this is still an honest question.
     
    X38 likes this.
  18. 19Eddy30
    Joined: Mar 27, 2011
    Posts: 2,314

    19Eddy30
    Member
    from VA

    Triangler 4 link more eye appealing then
    model A 4 bar plus you need pan bar ,
    I prefer to see one bar below the frame than two bars, I used 32 set up on stock boxed A frame made my own lower frame mount so It would be parallel to the ground at ride height ,
    Street & Drag With high Hp .
     
  19. ekimneirbo
    Joined: Apr 29, 2017
    Posts: 4,216

    ekimneirbo

    Don't know what you already have, and if you just prefer the model A frame.....or just have one and thats why you are using it. They are pretty weak as original, and a lot of people put 32 frame rails under their Model A bodies. Just thought I would mention that.
    As far as the four link goes, they can look nice, and they definitely improve ride and handling. Something to consider is driveshaft angle. With leaf springs, people set the rearend on a lesser angle because torque causes the rearend to rotate upward as power is applied. With a 4 link the rear will move up and down vertically but does not rotate upward.......so initial angle will be different than a leaf setup.
    Here are some pictures of 32 Ford frames that might give you some ideas. I only have 32 Pics, so not pressing that point, just saying that they may give you some ideas no matter what frame you use.
    32 Ford Frame 1.jpg
    32 Ford Frame 2.jpg
    32 Ford Frame 3.jpg
    32 Ford Frame 4.jpg
    32 Ford Frame 5.jpg
    32 Ford Frame 6.jpg 32 Ford Frame 7.jpg 32 Ford Frame 10.jpg
    BigBang32c.JPG
    Anyway, maybe a little food for thought.........:)
    I realize these are not "4 links", but it would not be difficult to run them instead of hairpins. It just gives you a chance to see some well done setups and maybe help with your build.
     
    Last edited: Dec 8, 2021
    TA DAD likes this.
  20. jaracer
    Joined: Oct 4, 2008
    Posts: 2,419

    jaracer
    Member

    The top bars are 17 1/2 and the bottom bars are 21 1/2. The car is all together now so I can't really tell you the angle on the top bars although I believe they point downward slightly. It's currently on the lift so the measurements were easy. The lift is a frame contact lift so the suspension is hanging down and angles aren't at ride height.
     
  21. grdra1
    Joined: May 20, 2013
    Posts: 526

    grdra1
    Member

    Jaracer, I meant the angle from housing to frame of the top bars, thanks Glen
     
  22. lostone
    Joined: Oct 13, 2013
    Posts: 2,820

    lostone
    Member
    from kansas

    Well gm has used triangulated 4 link since atleast 1960 if not longer.
     
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  23. gimpyshotrods
    Joined: May 20, 2009
    Posts: 23,264

    gimpyshotrods
    ALLIANCE MEMBER

    64_convertible_frame.jpg
     
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  24. gimpyshotrods
    Joined: May 20, 2009
    Posts: 23,264

    gimpyshotrods
    ALLIANCE MEMBER

    Cars that ride poorly, and have dangerous handling are traditional.

    Should we keep that tradition up? Where would one draw the line?
     
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  25. dmar836
    Joined: Oct 23, 2018
    Posts: 357

    dmar836
    Member

    Isn't that trailing link? I never thought those to be truly a 4 link suspension but I'm open to learn.
    Our Camry is pretty comfortable and safe. Is there an adapter out there in a catalog somewhere?
    I didn't bring any of that up - just honoring the forum rules regardless of my opinions on safety.
    D
     
  26. gimpyshotrods
    Joined: May 20, 2009
    Posts: 23,264

    gimpyshotrods
    ALLIANCE MEMBER

    This thread is about rear 4-link setups. The photo that I posted is of a pre 1965 chassis with a rear 4-link setup, triangulated,even.

    You asked, I delivered.

    Yes, it is trailing link. All common rear 4-link suspension systems are trailing link. I am not aware of a rear OEM leading link setup. I have seen a few on custom mini-trucks, but have no idea how they handle. Jeep used a leading-link 4-link on the FRONT of may new-generation SUV's from about 1984-on.

    Prior to the chassis that I posted, there were common 3-link systems, with the third-link being a wishbone, with the two attachment points on the chassis, and the third on the axle. As this attachment point was roughly 20-inches to the right, it made for an offset roll center, and uneven handling. The fourth link was added to eliminate that issue, all before 1965.
     
    Last edited: Dec 9, 2021
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  27. dmar836
    Joined: Oct 23, 2018
    Posts: 357

    dmar836
    Member

    Interesting. Thanks. My BMW moto has a leading link front end. Would be interesting handling in a car.
    Are there any pics of hot rod builds of the day using 4-link?
    Race cars maybe?
     
    Last edited: Dec 9, 2021
  28. gimpyshotrods
    Joined: May 20, 2009
    Posts: 23,264

    gimpyshotrods
    ALLIANCE MEMBER

    I am sure that there are. You would need to search for them, with the caveat that practical portable digital photography began in the 1990's.

    As for eyewitnesses, you should start another thread on the main board. I cannot help you here. I was manufactured in the 1969, to be released as a 1970 model.
     
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  29. gimpyshotrods
    Joined: May 20, 2009
    Posts: 23,264

    gimpyshotrods
    ALLIANCE MEMBER

    I am pretty sure that Jaugars had 4-links in the early 1960's, but I am no expert in the UK stuff.
     
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  30. Mimilan
    Joined: Jun 13, 2019
    Posts: 1,230

    Mimilan
    Member

    Back in the 70's I saw a speedway midget with trailing link lowers and leading link uppers.
    This was with an open tube axle and the links were attached to "birdcage" floating bearings.

    The birdcages acted like a bell-crank on a watts linkage [basically a longitudinal watts link]
    This caused the axle to travel on a vertical path straight up and down.

    Rover had a similar setup with the P6 ,but with a De-Dion rear axle [The De-Dion axle had a slip centre to allow for articulation]
    upload_2021-12-10_18-10-44.png

    On the front end of the Rover P6 they used a leading link upper A-Arm and a conventional "lateral" lower A-Arm
    upload_2021-12-10_18-14-56.png
     
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