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Compilation: Link ends, lets talk comparisons!

Discussion in 'Center Of Gravity' started by BadDog, Aug 19, 2004.

  1. BadDog

    BadDog SOL Staff Member Super Moderator Author

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    [ QUOTE ]
    I want to start a compilation of various topics relevant to those who are building serious off road rigs. Lots of stuff is touched on here and there, but finding it and putting it all together can be a problem. Lets try to get some of this stuff grouped together in one post. This is one such attempt among several. Lets try to keep this very focused and tech rich. NO POST PADDING! If you don't have something to add, please don't post fluff like the typical "that's cool" or similar having adding nothing relevant to the discussion.


    [/ QUOTE ]

    I'm hoping to start a full buggy this fall when things cool down and I get caught up on some stuff. But, no way I'm going to be ready with it for bb04 and there are other things I want to do before dismantling the truggy for parts going on the buggy. So, I'm looking to get some experience with link suspensions on the truggy before (most likely) screwing up the buggy with a "first try". That said, I need to order some sort of link ends, which of course can be reused on the buggy even if the links themselves need to be redone.

    What do you guys like and why?

    I'm a cheap-skate so price is important, but I don’t want to cut it too close.

    I also have a heavy truggy, and the buggy will be heavy too.

    Bushings:
    Brook has successfully run bushings on both ends for some time! I'm thinking I may even try this for a first pass just to get a feel for things without spending a lot of money. No expensive rod ends that I may not like, no threaded tube inserts that will be junk if I can't reuse the links, and will still work better than what I have (I hope). Knowing it's disposable also alleviates the problem (some claim) of splitting bushings frequently. I don't think Brook (The Freak) has split one yet that I recall. At least not enough to be a problem.

    Rod Ends:
    Thinking about rod ends, something like the QA1 1.25" rod ends with 1" eye or similar. Nice, beefy, lots of angle, but a bit pricey and they do wear out. Smaller joints wear out much faster due to smaller bearing surface. Common options in smaller sizes include 3/4 as well as 7/8 sizes. Misalignment bushings are often required which make the eye size even smaller. For instance, the 1" eye on the big joints becomes 3/4 with misalignment bushings, and the 3/4 becomes 5/8" (IIRC).

    Johnny/Jimmy joints:
    Several choices in various sizes and prices, but most of the cheaper ones have a small bolt (like 9/16). Up side is they are rebuildable and seem to last longer (large bearing surface area) between rebuilds. Can be had threaded like a rod end, or in "weld on" form.

    So, lets compare and contrast. Prices and manufacturer options along with pro/con would be great. I'll try to find some prices and more info on what I've been looking at to add later.

    <font color="red">
    PLEASE keep this technical! Don't respond with "I know a guy who runs "X" and it works great, so that's what I would run" type of stuff. Tell me what you think is best and why. Know a guy who runs it is fine, but tell me what makes it so great you would do the same thing…
    </font>


    Here, lets even make a poll out of this...
     
  2. BadDog

    BadDog SOL Staff Member Super Moderator Author

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    BTW, I'm also considering bushings on the axle with maybe Johnny Joints on the chassis side.

    It's also possible to need the beef of one of the big rod ends or a Jimmy Joint for things like Wishbone uppers where there is one joint with a tremendous load on it. This should be considered separately as a special case.
     
  3. Sandman

    Sandman 3/4 ton status Author

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    I'm going to throw my money on the Bushings mainly because I think they are cost effective and can take a beating in a harsh enviroment. I desighned correctly, I believe the travel that is looked for is available and I also wonder if rod ends are more of a fad then anything. I plan on linking up my rear this winter and planned on bushing ends. The question I have is: Are poly bushings better for the control or regular rubber bushings the way to go for the easier movement when looking for flex?
     
  4. Triaged

    Triaged 1/2 ton status

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    One thing you forgot to mention is that Brook's links have a large threaded coupling in them that allows them to rotate. If it wasn't for that I'm sure his bushings wouldn't have lasted.

    If you use a wishbone link make sure you have the axis of the bolt aligned with the load properly. The bolt on the single piviot end should point up and down (with respect to the link). Spherical bearings are only strong in the radial direction and if you put the bolt going side to side the side loads will put a axial load on the spherical bearing. Axial strength is only about 10% of what radial loading is!

    Also don't forget that if you use a spherical rod end on the end of a wishbone you will be loading the threaded shank in bending...the weakist way to load it.
     
  5. BadDog

    BadDog SOL Staff Member Super Moderator Author

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    Good points.

    If I do bushings, it will probably be poly. Rubber deflects a lot and costs much more.

    Isn't Brook's threaded rod only in the front radius arms? The rear links are solid tube if I'm not mistaken. As long as the links are aligned with the primary movement, then there seem to be relatively little bind, no worse than that seen in leaf suspensions at least...

    Also good point on the radial loading and shank in bending. It's amazing how many are exactly backwards, oriented to pop the eye out on side loads. As for the shank in bending, I wouldn't worry about that on to much on the top links. That single link would probably be one of the larger variety, and there is very little side load for a 1.25" shank compared to what you see landing on the bottom links.
     
  6. willyswanter

    willyswanter 1/2 ton status GMOTM Winner

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    I run the 1-1/4" heims at the axle and the large RE joints at the frame end. The RE joints are toast after only about 5 trips and 1000 miles or so. That was after greasing them practically every day as well. The plastic bushing material basically gets soft and squeezes out of the joint through the gaps between the end washers and the ball.
     
  7. Triaged

    Triaged 1/2 ton status

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    [ QUOTE ]
    Good points.

    If I do bushings, it will probably be poly. Rubber deflects a lot and costs much more.

    Isn't Brook's threaded rod only in the front radius arms? The rear links are solid tube if I'm not mistaken. As long as the links are aligned with the primary movement, then there seem to be relatively little bind, no worse than that seen in leaf suspensions at least...


    [/ QUOTE ]

    Yep...solid in the rear...been a while ago now /forums/images/graemlins/whistling.gif
    [​IMG]
     
  8. bgreen

    bgreen 1/2 ton status

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    Here is the PM I sent baddog yesterday... I finally signed up, so I might as well just post it here myself.

    [ QUOTE ]
    You were correct that I havent split out a bushing on my rear 4 link yet. The only thing thats split is the flanges on the sides of the bushings. So, really I havent "had" to replace any of the bushings yet. Been about 4 seasons now? I think.

    Just a few weekends ago I finally did replace most of the bushings though. Not cause I had to, but because I developed a clunk, that I could not find, so I ordered new bushings and inner sleeves. Since I had hte links out to inspect the bushings, I went ahead and replaced about half of the bushings.

    The inner sleeves wear out, causing some extra clearance on the bolt, and the actual bushing itself wollers out some, causing some extra clearance between the sleeve and bushing. I think that with your terrain you will not have the same success I have had. While I do ride alot of washouts and get pretty twisted up from time to time, I dont do it nearly as much as someone who wheels in the rocks all the time.

    I am considering threading my rear links like the front. At the same time, I will likely do a double triangulated 4 link instead of the |\ /| I have now. I think if I did the threaded deals, I would be able to get more life out of the bushings, and still have a quiet, comfortable ride. Without spending a bunch of money on big heims.

    So far I have not bent any of the 9/16 bolts, but I have worn out the holes in almost all of my 1/4" thick brackets. From now on, all my suspension brackets will be 3/16 (the ones that can be hit on ricks will be 1/4") with weld on washers, to increase the bearing area where the bolt goes through. (I am pretty sure most of the problem here is from not keeping the bolts torqued properly, but still)

    [/ QUOTE ]
     
  9. heavytlc

    heavytlc Registered Member

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    I have used bushings, 3/4- 11/4 heims, JJoints,and RE joints. Each one has +-, depending on link angle/design, travel, enviroment, weight, upkeep, cost. Bushings have to have a thick sleeve that the bolt passes through, if not the bolt will move against the bracket, enlarging the holes, and ultimately killing the bushing. ORD makes real nice bushing assembleys, I use a ton of them, and the sleeves that Steven uses are topnotch, not junk like some. The problem with bushings, is they do not allow for very much angle, and are best suited for the chassis side of a link. Using them at the frame side, does a good job of isolating vibration, and allows for some give in the link geometery. At the axle side you can use Heims, or one of the other style joints(jj,re). They all have enough range of motion for just about any suspention style. With the heims, 3/4 works for the lower, and I am happy with them up to a 4+klbs truck. Only the QA1, 2pc with kevlar, never a 3pc, ever, at all, under any condition. The wall is wayyyy to thin on the 3pc. Anyway the heims live a good life down at the axle, the bushing at the frame help some of the shockloading. The uppers same thing, 3\4, unless it is wishbone, than I would much rather use 11/4, mounted with the bolt on the verticle plain.
    On the RE joint/ JJoint, I hate the snapring on the JJ, the threaded style RE joint is more user friendly, and easier to assemble/service, otherwise they are the same for comparison. Price wise, they are the same as the QA1 3/4 heim(around 30) they can be used in place of the bushings, or the heim, or both. the joints are rebuildable, and give good life, I have never broken one,at least to to the point it was unuseable(same with QA1 3/4 2pc heim). The big down side to the RE/JJ joint is the 9/16 bolt. It is plenty strong, but AA mfg,and the chassis shop or who ever you get prefab brackets from make everything you need, but only in 1/2 and 3/4. If you want to make all of your own brackets then this is not a big deal, but I try to limit building stuff that I can buy for 1-2dollars each.
    As I always preach limit straps, bumb stops, stout links(I like 1.50x .500wall) . Once you have the super flexy ramp champ, you will miss being able to carry a tire, sometimes it is all about contact pressure, not 4tires on the ground.
    My new project is leaf front and rear, and $$$ is not the reason, but I would not tell anyone not to go link.


    QA1 2pc heim= &lt;$30 Summit
    RE/JJ joint large= $30-35Where ever, I am unhappy with the source I have, so no pimping for them
    Bushings, complete with bolt,sleeve, tube and all $10-15 OffroadDesign, they have lots of sizes and dia.
     
  10. Greg72

    Greg72 "Might As Well..." Staff Member Super Moderator

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    Russ,


    You probably remember this, but I'll post it for the benefit of the others.

    I ended up buying the TeraFlex rod ends for my own link project. They are the 1.25" style with a beefy forged end, but what makes them nice is that the "guts" are rebuildable because the joint is modular and has a snap ring setup machined into it. You can replace the center with rubber, steel or a urethane setup depending on what you are using it for, and based on how much noise you want to put up with.

    The ends themselves are probably no more expensive than a regular heim (around $80 ea IIRC), but you can buy the rebuild kits for around $10. One of the real issues I had with building a link suspension (with around 16 heims) was the thought of having to replace them every year or so ($$$$$) and the fact that I'd have to completely re-measure and re-tweak all of my link lengths each time I unscrewed the ends from the links to replace them. With the TeraFlex units, I can just remove the clips and rebuild the ends while they are still connected to the link, and I can redo the whole suspension for less than $200.

    I can't give you any "hands on" experience yet since they are still in a moving box buried somewhere in my garage....but I actually DO own them and intend to set them up in a suspension "mock up" once I get my East Coast "Man Space" up and running.....

    /forums/images/graemlins/thumb.gif
     

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