Thoughts on Short Arm 3 Link

I searched and didn't come up with much more than XJRanger's thread that no longer has pics. My D30 has raised upper and lower mounts. Running fixed length RE Superflex lowers and homemade .25" wall uppers. 4.5" lift w/ 32s, looking to eventually run 33s or 35s with little or no more lift.

After wheeling a few times with the beefed links I have, my truss cracked around the weld at my pass side link tower. I believe this to be largely due to the binding associated with a 4 link coupled with the leverage of a tall link tower welded to Ballistic's 1/8" steel truss.

I was planning to just redo everything with a midarm with stiffeners, but I don't really feel the need to extend my links as it rides and flexes well as is. Time is also bit of an issue. With the appropriate beefing of the stock driver's side frame mount, how awful of an idea is running a single stock length upper using the 7/8" heims already enroute to me?

i'd worry about THE SINGLE unibody side upper control arm mount, that thing is like sheet metal.....

The stock UCA brackets brake off normally so you would have to cut one off and remake it. I run mid arms 3 link but my UCA frame side mount is about three inches below and thee inches behind the stock UCA hole.

I run the larger 2 5/8 joints for my uppers and lowers using 9/16" bolts as well.

xjh3 said:

With the appropriate beefing of the stock driver's side frame mount

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I would either reinforce or rebuild the frame end mount for the upper.

xjh3 said:

I would either reinforce or rebuild the frame end mount for the upper.

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You would need to plate the 'hard to get' inside as I have seen that thin sheet metal rip out when the UCA breaks off.

Best bet is to cut it off and re-do it but when you do that you might as well relocagte the hole and locate it into a position that is better for a three link (almost flat UCA).

cracker said:

Best bet is to cut it off

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Done! Looking at what is there, I think there is plenty to plate over in order to provide the strength needed. Doesn't look like I will need to move the hole much to make the upper/lower links parallel. Should be pretty simple.

xjh3 said:

Done! Looking at what is there, I think there is plenty to plate over in order to provide the strength needed. Doesn't look like I will need to move the hole much to make the upper/lower links parallel. Should be pretty simple.

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Focus on making the UCA flat more than parallel with the LCA.

xjh3 said:

After wheeling a few times with the beefed links I have, my truss cracked around the weld at my pass side link tower. I believe this to be largely due to the binding associated with a 4 link coupled with the leverage of a tall link tower welded to Ballistic's 1/8" steel truss.

Click to expand...

not to knock your skill or who ever fabbed your truss... and im no engineer, but i feel this is not accurate. i would suspect the design or integrity of the welds before blaming the inherent bind of a 4 link as the sole factor for the truss's failure.

I feel its accurate if its welded to 1/8" and he used all hard joints.

:gee:

thats what i get for posting late at night. i thought it read that the truss itself was failing. if i understand correctly is the CA mount itself thats failing where it attaches to the 1/8" truss?

I used all hard joints on the axle ends, frame ends were all rubber.



Not sure how well you can see from the picture, but in person it is pretty clear to me that the weld itself did not crack. The entire weld joint, including the 1/8", pulled out of the truss (not a case of inadequate penetration, either.)

When I raised the LCA mounts I also raised the uppers. That made the link tower quite tall. I still think the leverage of such a tall tower combined with the binding was working it back and forth slightly which sort of work hardened the 1/8" on the truss. I thought spanning the entire width of the truss would be strong enough. In hindsight, probably a bad design on my part.

I thought of plating the top of the truss with 1/4" and welding the tower to that, but I think that would just make it take longer to do the same thing again. It seemed to me like the only way to make such a tall link tower work would be to have the tower weld to the actual axle tube and rise out of the truss. Cutting it off and going with a 3 link seemed like a better plan to me.

lets see the rest of the link tower.... all too often, i see people skimp on the link towers... some people only use 2 peices, left and right, without even boxing it in!

pure retardation. theres nothing in the way, WHY NOT throw in an extra gusset?
thanks for posting, weve done a few ballistic truss's, so will be keeping an eye out for cracks. (what else is new?)

I could have gusseted the other side, but what would have probably helped more is if I had more gusset running parallel with the front brake edge on the truss like I did on the back. Should have run two triangles parallel to the edge, then made a flat piece to box them in. Oh well.