Register now to get rid of these ads!

Technical Leaf-Link Rear Suspension... Why Not?

Discussion in 'The Hokey Ass Message Board' started by Crazy Steve, Mar 20, 2021.

  1. I've seen this type rear suspension rarely used, and wonder why. Generally, most guys go either four-link or ladder bars, but I'm looking for a simpler, less space-consuming design.

    My reasoning behind this is this isn't for a race car. I'm looking at a lowered custom, so race duty isn't needed, just something to prevent spring wind-up, particularly if lowering blocks would normally be used. I understand that most custom guys would use a four link or truck-arm style suspension with air bags for this, but I have no interest in bags (and their expense/complications) and don't care about 'laying frame'. Retaining ride quality is important also, so ladder bars are out. But because the car is lowered, I also don't want anything hanging down like slapper bars.

    Fabbing an axle pivot point below the leaf spring would be fairly simple, add the upper links and triangulating them some gives most of the same benefit as a track bar. This would also allow adjusting ride height easily also. Basically the same design as most GM coil-sprung rear suspensions, just with leaf springs instead of coils.

    Anybody with experience with this? Tips, comments?
     
  2. Are you meaning semi-eliptic leaf springs, (like half of a conventional parallel leaf spring arrangement)?
    Why not just use parallel leafs?
     
  3. Tim
    Joined: Mar 2, 2001
    Posts: 19,637

    Tim
    Member
    from KCMO

    I think you’re taking about a quarter elliptical set up? @Malcolm has it on the back of his roadster. Not super un common to see on hot rods
     
  4. The idea is to use the OEM parallel leafs with upper links. I also wouldn't be clamping the front half of the spring together like the Mopar pro stockers. Kind of a 'traction masters' arrangement, with the bar above the spring instead of below.
     
    1934coupe likes this.
  5. TA DAD
    Joined: Mar 2, 2014
    Posts: 1,565

    TA DAD
    Member
    from NC

    Using the springs and upper links is what Chrysler did years ago. Leak link is what they called it. Harsh set up .
     
  6. oldiron 440
    Joined: Dec 12, 2018
    Posts: 3,828

    oldiron 440
    Member

    That didn't necessarily work..
     
  7. Mimilan
    Joined: Jun 13, 2019
    Posts: 1,235

    Mimilan
    Member

    Shelby did exactly that on GT350R's except they were call "Traction Override Bars"
    upload_2021-3-21_13-15-24.png

    upload_2021-3-21_13-14-36.png

    Ford also did thie OEM on English Mk1 GT Cortinas [except they were inboard slightly]

    This system works well if there isn't too much arch in the springs [due to forward thrust]
     
    Last edited: Mar 20, 2021
    seb fontana likes this.
  8. TA DAD
    Joined: Mar 2, 2014
    Posts: 1,565

    TA DAD
    Member
    from NC

    Correct from what I remember,
    We did this under a Fairlane and it seems to me you had to put floaters on the axle also. That has been decades ago for me.
     
  9. Rusty O'Toole
    Joined: Sep 17, 2006
    Posts: 9,756

    Rusty O'Toole
    Member

    All you need is a single Traction Master type link for a reaction point. Arrange it so a line drawn through the pivot points coincides with the front spring mount.
     
  10. redo32
    Joined: Jul 16, 2008
    Posts: 2,286

    redo32
    Member

    On my '48 Ford p/u I moved the spring hangers up on the frame and removed a couple of leafs. The springs were weak enough to wrap up and I broke a couple of u bolts holding the u joint. It was a 10 bolt GM rear, so I built a couple of links from the stock cast brackets out to the frame. I put 100K miles on it. Rode great, handled great.
     
  11. grumpy65
    Joined: Dec 19, 2017
    Posts: 920

    grumpy65

  12. lostone
    Joined: Oct 13, 2013
    Posts: 3,463

    lostone
    Member
    from kansas

    Yeah if your going to run leafs with upper links just put a full floating kit on it and then it gives you alot more options....
     
  13. oldiron 440
    Joined: Dec 12, 2018
    Posts: 3,828

    oldiron 440
    Member

    It was common to bend the springs.
     
  14. greybeard360
    Joined: Feb 28, 2008
    Posts: 2,097

    greybeard360
    Member

    AMX and SCRambler used a similar setup that worked pretty good.
     
    kidcampbell71 likes this.
  15. Jaguar uses two coil over shocks per side on the IRS. Four total coilover shocks.

    Sent from my SM-A102U using The H.A.M.B. mobile app
     
  16. enjenjo
    Joined: Mar 2, 2001
    Posts: 2,767

    enjenjo
    Member
    from swanton oh

    I've built a couple leaf ling rear axles setups. They work , but not as well as a four link. But they are easy to do. The pictures a couple posts back are pretty much the way to do it. Upper bars should be as long as possible for pinion angle changes. And a Panhard bar sure helps. I have an S10 running around with a stepped and narrowed rear frame half, 31" Micky's and a Blown 400 small block and he has never broke anything in over 20 years. It also runs 10s in street trim.
     
    AHotRod likes this.
  17. So what I'm getting out of all this is a leaf-link isn't the best choice for drag racing but would be suitable for a street deal. That's all I'm after, the car is a 4000 lb convertible and I just want to eliminate any possibility of axle tramp. Do my homework and pay attention to the geometry and it should be fine.

    I'm not adverse to the Jag rear (I've got four of them... ;)) but that's a different can of worms. Gear ratio changes are expensive/difficult and while their Dana 44-based center section is pretty stout, it's not as tough as a 9" which is already in the car...
     
  18. 1934coupe
    Joined: Feb 22, 2007
    Posts: 5,216

    1934coupe
    Member

    Steve 59 - 62 Corvette had what you are talking about with the bar above the rear. Simple and seemed to work fine.

    Pat
     
  19. Hnstray
    Joined: Aug 23, 2009
    Posts: 12,355

    Hnstray
    ALLIANCE MEMBER
    from Quincy, IL

    @Crazy Steve

    Ist generation Explorers used leaf springs with a top mounted link, similar to @Mimilan comment and photo for the Shelby GT350R.

    Ray
     
  20. kabinenroller
    Joined: Jan 26, 2012
    Posts: 1,298

    kabinenroller
    Member

    When I fabricated the rear suspension for the Comet I used leaf springs with tubular bars mounted under the housing going forward to the front eye of the spring. The leafs are relocated inboard 2 1/2”, the front of the bars mount to the same through bolt that locates the front spring eye, the rear of the bar in in the center line of the axle under the housing. I put 1,000 miles on the car before the weather closed in and I am very pleased with the way the rear suspension works. There is no bind and the car rides well.
    My opinion is that if the geometry is correct a Leaf/Link system a good option.
    6C8E6F2B-30D2-4D04-82E4-495C80D34434.jpeg 58700AEB-461E-446E-916D-6527BD4B67BF.jpeg
     
  21. 56MercMan
    Joined: May 22, 2008
    Posts: 140

    56MercMan
    Member

    I know this is an old thread (sorry) but I did not want to start a new thread as this one has some good info already.

    I was thinking of adding 2 lower arms to my rear end similar to what @kabinenroller has above but longer and made of 2x2 box. I would then be adding airbags to that. I can not see any downside but wanted to see if anyone has tried this or sees something I am not. (I know how to set up arms so there is no binding and all that fun from my off road fab experiences)

    I currently have 2 leaves and 3 inch blocks in the rear. It is an air over leaf setup and rides pretty stiff/bouncy due to the high pressure needed to get the car up and as many know with minimal leaves we get axle wrap which will eventually break the leaves. Also the suspension travel is limited to the bag travel which would only come into play if I needed to change a tire.

    I thought if I could add some 2x2 "traction" bars to the bottom of the rear end and run 2600 bags off those arms to provide the lift that would work. It would minimize the axle wrap acting as a traction bar which would extend the life of the leaves and it would provide me a better ride due to the 2600 bags being an air over link design. I am not wanting to go to full 4 link because I do not want to modify the body (Rear seat area). Also if I tried parallel 4 link the pan hard is right where the gas tank is. I have searched everywhere and could not find any info except this thread.
     
  22. RodStRace
    Joined: Dec 7, 2007
    Posts: 7,785

    RodStRace
    Member

    I'd check out mini truck and slammed air ride forums. They have got to have more experience than most here.
    The air over leaf thing seems like a partial solution. The leafs have to support and locate the rear axle, but also flex enough that air changes ride height. The front pivots would need to be strong, yet compliant and quiet.

    This lost the pictures. :(
    https://www.jalopyjournal.com/forum/threads/1956-mercury-monterey-on-airride.924102/

    Bad chad did one. I just found the link, didn't watch.
    www.youtube.com/watch?v=nMzW35rgOZo
     
  23. '29 Gizmo
    Joined: Nov 6, 2022
    Posts: 1,132

    '29 Gizmo
    Member
    from UK

    Austin seven rear suspension. Quarter eliptic springs and torque tube.

    Doesn't get much simpler than this.

    A7_Chassis_4.jpg
     
    56MercMan likes this.
  24. 56MercMan
    Joined: May 22, 2008
    Posts: 140

    56MercMan
    Member

    I have seen 1/4 elliptical on old off road race trucks also.
     
  25. 56MercMan
    Joined: May 22, 2008
    Posts: 140

    56MercMan
    Member

    I appreciate the links. I read that 56 merc thread before I posted in here. Found pics of his car (Really nice) but none of the actual suspension set up.

    I did see the bad Chad vid previously. He is running a mono leaf with blocks and shockwave bags. Very similar to my current set up. The mono leaf is scary to me and he is going to have a similar ride as mine unless the shockwaves are that much better then a bag and a shock. Plus the axle wrap would be even worse then my 2 leafs (Assuming my extra leaf actually helps).

    Basically the leafs in my idea would locate the axle front/back and side/side. The bars would simply provide anti axle wrap and act as the actual spring due to the air.
     
  26. Gofannon
    Joined: Feb 8, 2007
    Posts: 985

    Gofannon
    Member

    Austin 7s handle like crap, something to do with wheelbase changing with suspension travel.
     
  27. '29 Gizmo
    Joined: Nov 6, 2022
    Posts: 1,132

    '29 Gizmo
    Member
    from UK

    Bruce Mclaren's first race car was an Austin 7. They are still popular with vintage race series today.
     
    rod1 likes this.
  28. lake_harley
    Joined: Jun 4, 2017
    Posts: 2,364

    lake_harley
    Member

    I know this is an old thread but '29 Gizmo's post a few posts back seems to have hit on what the original post was asking about. I think the Austin 7 with an addition of upper links to handle torque is on target. Seems many posts went different directions....which is traditional HAMB practice.

    Someone who I think was from Iowa built a Model A with quarter elliptics and upper links a few years ago and actually did some drag racing with it. As I recall I think it worked quite well.

    Lynn
     

Share This Page

Register now to get rid of these ads!

Archive

Copyright © 1995-2021 The Jalopy Journal: Steal our stuff, we'll kick your teeth in. Terms of Service. Privacy Policy.

Atomic Industry
Forum software by XenForo™ ©2010-2014 XenForo Ltd.