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Wristing control arms

Discussion in '80-Series Tech' started by jmaddocks, Aug 3, 2005.

  1. jmaddocks

    jmaddocks

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    Hope I'm not beating a dead horse here, but I was wondering if anyone has played around w/ wristing one of the control arms to gain front end articulation. There is a lot of talk on this on the Rover and Bronco forums -- the attached picture shows a wristed Bronco control arm.

    Has anyone disconnected one of the control arm mounting bolts, such as the forward driver's side one? This technique was mentioned by the Rover guys (the arm would be disconnected at the trailhead). Other method would be to fabricate a wristed control arm for one side.

    Clearly, the axle torsional loads would be transferred through a single control arm vice both of them -- I don't have a feel for whether the axle housing and non-wristed control arm (and bushings, for that matter...) could handle the additional stress. Thoughts?

    Jason
     
  2. mabrodis

    mabrodis

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    I brought this up a long time ago, although it wasn't called 'wristed', dang I can't remember the term though, but yes Land Rover groups do it alot.

    IIRC the concensus was it probably will help wheel travel/suspension-binding but how much, at at what price. A Cruiser flexes very well with nothing more than new springs and shocks, maybe more so than most vehicles with such minor modifications.

    Personally I don't see that much value in excess wheel travel, it usually makes the vehicle more unsafe offroad, less stable and with lockers front and rear it's rare that you need all 4 tires on the ground to make it up something, can happen yes, but rare.

    Shoot, I still can't think of the term that is normally called, I want to say hinged pin, but that doesn't sound right.
     
  3. Gumby

    Gumby Supamod Staff Member s-Moderator

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    I've always heard it reffered to as wristed. Perhaps it's more of a Bronco owners term. My 40 has 80 series control arms. the right side is perminantly wristed as it will never see the street. In fact, I cut the front bushing off. It now flexes enough that the panhard pulls the tire into the spring long before it lifts the off side tire.

    It's true a locked 80 does not need four tires in contact with the ground. I have lifted a tire a couple of times and have to say it would be nice if the 80 flexed a bit more. Exactly why mine now has L shocks, sway bar extentions and brake line extensions.
     
  4. jmaddocks

    jmaddocks

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    Just as a little science experiment, I played around w/ removing the forward bolt on the driver's side control arm. Subsequent runs up the ramp showed a pretty dramatic improvement in front-end articulation, and I was able to stuff to the bumpstop and reach max extension on the extended shock. Attached is a pic w/ the ghetto wristed control arm:
     
  5. Josh83

    Josh83

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    What shocks are you running? Are you running front bump stops? Extended brake lines? If not, were they binding?
     
  6. LandCruiserPhil

    LandCruiserPhil Peter Pan Syndrome Supporting Vendor

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    I have wristed arms on my junk and they are different from the single hinged arm on a Bronco. The wristed arms improve the articulation some but what keeps me from utilizing all 14" of shock travel is the pan hard. The pan hard causes a great amount of side pressure where the arm mounts to axle. You have probably heard about the Aussies breaking the mount where the arm bolts on to the axle. The DS will droop slightly more then the PS because it has less pressure from the pan hard. I have considered dropping the pan hard 2" to improve this. But even at the droop I currently have I feel it stresses the joint at the steering arm too much with my lift.

    The idea I came up with to correct this is to obtain a PS knuckle arm off of a RH drive 80, flip and lower the pan hard and go to cross over steering. Any thoughts?
    bronco hinged arm.jpg
     
  7. jmaddocks

    jmaddocks

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    I'm just running N73/N74E for now, but I'll probably eventually go to N74L or Bilsteins in the rear. The standard front bumpstop (under the coil spring mount) was just touching. I'm also running front frame-mounted bumpstops from a Toyota truck -- actually, they started life as the rear bumpstops on one of those goofy looking little vans -- for future growth. The OEM brake lines were not binding.

    Interestingly, even with the bumpstop touching, the front shocks were a good three inches from being fully compressed (I've got all my shocks marked w/ a Sharpie). In other words, even w/ the wristed arm, I couldn't use all the front shocks' travel. I may have to look into lowering the upper shock mounts in the future, esp. if I lower the bumpstops for larger tires.
     
  8. clownmidget

    clownmidget

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    Phil, can you post a pic of those arms mounted up?

    jmaddocks, do you have the front sway bar attached in that flex shot?
     
  9. jmaddocks

    jmaddocks

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    I run w/ both sway bars removed, except on long highway trips. Sways are removed in that pic.

    Jason
     
  10. lcwizard

    lcwizard Supporting Vendor

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    I've been tossing the idea around, putting in production, a pair of longer arms with one of the bolts eliminated. The side that retains 2 bolts will need to be reinforced since i don't believe the stock brackets are adequate to handle the double duty. As phil has stated you will need a drop panhard bracket, despite the bumpsteer whining going around, and
    a spherical ball end on one end of the panhard wouldn't hurt. spherical ends on the frame side of the radius would probably improve the situation also.
    And yes, the radius arms would come with drop brackets
     
  11. clownmidget

    clownmidget

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    Wanted to revive this since jmaddocks has the newer thread with pics of his etc.


    Phil, grace us with a pic of those arms already :)
     
  12. alia176

    alia176

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  13. LandCruiserPhil

    LandCruiserPhil Peter Pan Syndrome Supporting Vendor

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    There is really nothing you can see because the joint is booted.

    Here is a picture of a mod I have been eyeing lately. This combined with a panhard drop possibly Daves would make the wristed arms a lot more effective.

    Jason how much travel are you trying to get? And with the testing you have done how much travel do you have now?
    Hi steer 1 mud.jpg
     
  14. Riad

    Riad

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    Yeah I would also like to know the work involved in flipping the front control arms. As far as I can see, you have to torch those brackets off and weld'em on the other side of the tube. Now if you add wristing arms and panhard ros assembly with it, man that would be interesting to see. Cool idea, it would be great to see the numbers such as before and after pinion angle, vibration (if any), articulation and how the truck handles this mod.
     
  15. jmaddocks

    jmaddocks

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    I really don't have any specific goals in mind -- I just want to better match the front and rear articulation. As for the testing, I was mainly just curious to see what would happen.

    With the control arms bolted up and sways removed, I could never even come close to using all the travel of my N73s. As a result, I just couldn't justify moving up to N73Ls, even w/ longer springs. With the wristed arm, I reached full extension on the drooped shock, and compression to the bumpstop (just touching) on the other side. I'm very happy w/ that. I think I could exploit all the travel of the N73Ls and may move up eventually.

    Jason
     
  16. clownmidget

    clownmidget

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    Bjowett did this a while back and had good results.
    P1010030_1.jpg