Binding in upper control arm??

Aggressive1

Aggressive1

Well-Known Member
Joined
Apr 19, 2005
Location
Myrtle Beach
I am setting up a tri link upper control arm and can't figure out whether I will have binding in the urethane joints (on the frame) if I make the mounts point towards the top of the diff. I need the upper to leave no latteral movment so I don't have to run a track bar in the rear.
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Will the 1st one work or do I need to do the second or third design?
 
After carefull review and countless hours of measuring and mockup........I have no idea....:) :) :) :) :) :)

Looks sweet Dave....Need a hand this weekend. I think the wife would like to Myrtle Beach Drive
 
The second drawing will give you better everything, assuming your brackets can handle the sideloads. In the first drawing, most of the stress will be on the bolts, in the second, it will be distributed between the bolts and the brackets, mostly into the brackets (as if it were sliding along the bolt, only that shouldn't happen). The first will give you binding, with negligible benefit as far as lateral movement. The second will give you free up and down motion, and still provide enough lateral control.
 
Ok, I'll say the frame mounts straight back for compression and droop because if its angled the tubes and mounts (I guess you mean like shackle mounts) will converge when out of the neutral position. The banking of the axle in relation to the frame will be handled by that rear superflex joint. I think that axle superflex joint mount should be perfectly centered though. Friend of mine sorta runs that set up backwards, 2 shackle axle mounts and one pivot at the tranny crossmember. Just my thoughts, right or wrong.

Scott
 
Matt and Scott, thanks alot for the information. I ran it through my head many times but could not figure out if there would be binding or not. I will truss the sides of the brackets and box them top and bottem (with enough clearence for the joint) and the upper truss can be found at:
http://www.usjeeps.com/forum/viewtopic.php?t=869&start=60
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p26-1141011154.jpg
 
Your first drawing will bind using bushings, since the movement in the arm at the frame end will be up/down pivot point - the bushings facing each other will counter act each others movement. The second drawing is best, it will not limit lateral movement as long as the mounts/bushings, etc can withstand the load. A 3 link will almost double the forces of a 4 link so build it with some beef.
 
If possible, I would run the side supports on the rear all the way up to where the bolt goes through. During hard cornering, you may see up to .8G's, which is about 1600lbs of force on a 2000lb rear weight. This can be much higher due to dynamic loads like bouncing off of a rock and such. While what you have shown in the first picture will probably hold, having the triangulated supports go to the area where the bolt is will definitely make it much stronger. Even welding some plate from the supports to the top of the tabs would help tremendously.
 
Heres a pic of my rear 3 link. Disregard the tube truss, cause it lasted about .4 seconds before it twisted into a pretzel.
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Heres it flexing, so it kinda worked
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The truss is welded together now (no pics right now) and they are up against the bolt like you said. I'll add some 1/4" plate up to the top like you said. I like that idea.
 
How common is it for the ball to pop out in an RE Flex joint? I would think it would be better to have the bolt vertical since the joint will be main one locating the axle.
 
Good call. I was trying to remember last night why I always see the bolt vertical in all the bolt on 3link kits.
 
Aggressive1 said:
Damn, wish ya'll had thought about that BEFORE I welded it together. Damn.
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Dont sweat it, I ran mine very hard with the bolt parallel to the axle with no problems. I think the RE joint has 35* deflection, just flex your rear axle out and see if the joint maxs out, chances are your shocks will limit you far before the joint maxs out. Or you could always put a band-aid on it and run limit straps.
 
If you check the specs on the joint, and the max load in that direction is 2500lbs or great, you should be fine. Imagine trying to break the joint in a press, you will probably need more than a ton of force.
 
Aggressive1 said:
Good deal. Hoping to have this thing together by the weekend.
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Cool, shoot us a pic of the finito producto.





Oh yea, when its done are you actually going to wheel it this time round :flipoff2:
 
Forgot to put pics up:
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Everything worked great except I've got TOO much antisquat. When I put it in gear its twists pretty bad and lifts up one side. Working on that and adding some additional beaf to the upper control arm before I take on the front.
 
Here are the calculations for the links after I figured the adjustments that I could do on the upper control arm mounts. I have room to move the mounts up at the frame and down at the axle. I thought the more verticle seperation between the upper and lower at the axle, the better when I built the set up but now I am finding out that was incorred. I started out with 200% antisquat and as you can see I'm down to 175% but I need to be at 100% right? I read something about being able to just put a limiting strap in the center of the diff would help.
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p26-1146535959.jpg
 
yeah, 175% is too much. I'd shoot for more like 80%, at least thats what I was shooting for on my yet un-finished buggy...

the vertical seperation between your lower and upper mount looks to be way too small. move the upper up and lower the lower mounts and it looks like it'll help.

Rob
 
Certainly go up to the upper bolt on your frame end mount, if not even higher than that...

You've got body interference beyond that, so you can't go higher on that upper mount.. Can you lower the frame end lower link mount at all?

More separation at the frame will help you get what I think you're wanting..
 
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