Heim Joints

[muddypunk]

So my Best man has this Huge Dodge pickup with like 10 inches of lift all links have Heim's and his right uca flops back and forth on the ball of the Heim is this normal? Or do I need to find some new Heim's for him .
The rest of his Joints are tight there is NO clunking the arm just flops left and right ? Please Help and Thank you

 

[rockclimber]

what do you mean by flops?

if you mean that the arm twists because the heims are misaligning, then no, don't worry about it.

pics would help.

 

[muddypunk]

If I grab the arm I can Twist it left till the Heim hit the uca bucket and twist it right till it hits the uca bucket the ball part that the bolt goes threw is good it does not move at all

 

[WaXJ_Skier]

Sounds normal, as long as the body is rotating around the ball you are fine.

 

[redrider2911]

Yes. Normal.

Long explanation.
Probably the reason you can turn that one and not the others is because how the rig is sitting. An axle only needs 4 links to hold it in place. A lower on the driver and passenger side to stop the axle from moving forward or backward under the rig. A upper on one side to stop the axle from rotating (axle wrap). And a panhard to stop the axle from moving side to side under the rig. This is an example of a 3 link. Where there is force at the joints you will not be able to rotate the arms easily by hand. So on my 3 link I cant rotate the upper and lower arms on the passenger side because there are external forces on the joints while stopping the axle from rotating. However I can very easily rotate the single driver side lower because the only force is forward and back movement. While sitting still on level ground there isnt any applied force.

You might be saying wait, this is a 4 link. The same concept still applies except technically you should be able to move 2 link on the same side easily if on perfecly flat ground and the front or rear end has been aligned properly. Since a 4 link binds as soon as a little flex comes into play then all the arms tighten up from pushing or pulling forces. Thats why you dont want to run solid joint (heims) on all sides of a 4 link + panhard.

 

[muddypunk]

All 4 links are heims but the Trac bar has rubber so do the rear torq bars

 

[GlueNTape]

Since a 4 link binds as soon as a little flex comes into play

:bs::conceited

 

[redrider2911]

:bs::conceited

Its a fact. Thats why you never see a 4 link + panhard with solid joints on every side, there is inherent bind. A triangulated 4 link with out a panhard yes...

 

[redrider2911]

http://www.pirate4x4.com/forum/showthread.php?t=829792

Looking at the link calculator... it seems to me that the net change in vector at the x-axis for upper and lower links will give me what I'm looking for? If so, that would indicate that 0 bump on one side with -8 of droop (worst combination) on the other side, would require .470" inches of give distributed over 4-links.

I would have to put some thought into the link length change from the calculator for no bind. If it is .470"/4=.118" (about 1/8") good luck compressing a link that much. Chances are it would just flex the axle brackets and the frame. If you are ok with the frame flexing that much go for it

 

[XJOFFROAD]

Its a fact. Thats why you never see a 4 link + panhard with solid joints on every side, there is inherent bind. A triangulated 4 link with out a panhard yes...

dont have time to do research but isnt BDS long arm kit a 4 link? they have solid joints on both ends.........

 

[redrider2911]

dont have time to do research but isnt BDS long arm kit a 4 link? they have solid joints on both ends.........

Funny that you would mention that. I've been talking to a fellow jeeper on Facebook who's BDS 4 link crossmember has severly cracked twice on him now. He has been trying to figure out why but now that it has been brought to my attention that they are supplying all "solid" joints, I am rest assured to say that that would be the issue.

 

[GlueNTape]

I run the full traction 4 link. I love how it performs. I haven't had any issues.

What constitutes a solid joint?

This message sent from my phone.. which contains glue... no tape... yet..

 

[redrider2911]

Heim joints specifically. It's a really broad term. Joints that don't have alot of give in them. Some ballistic joints where you can set preloads with nylon races. Some of the other joints with a thicker rubber race is kind of a cross between. Forged poly ballistic joints and other rubber joints/bushings would be soft. Depending on the geometry of the kit the joint needs to be able to squish or stretch enough for the amount of bind when flexing.