front suspension testing

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Yeah, Kevin I thought about the alignment of the "flex" holes in the OEM bushings but it ended up not mattering. The brackets on the axle, specifically the front-most mount catches and binds the bushing eyes on the control arms (both stock and Outback) eventually. On that last shot with the shocks off the entire face of the control arm bushing mount was completely flat against the axle mount bracket - looked like they were welded together. I can only imagine the force on those brackets as Dan brought up.

AMMO, you know my truck only works every 3rd weekend...but really I just need some tires before I go out. Those BFG's have to last a few more months.
 
Awesome write-up. Thanks. Well, i guess it's back to the drawing board. I figured those trick twisty arms you had would make a world of difference. Guess not.
 
Just a FYI on the forklift vs real world traveling. We have repeated proven that when we test on the ramp or forklift, and we think we have no rubbing, etc etc, when we get on the trail you have different forces working on the truck and it will actually articulate more than in a controlled environment.

Also, the Outback arms eliminated one of the binding points, but not all. The biggest one is (if you look at the suspension from the top) that you are trying to deform a square made between the control arms, and the axle, with the control arm frame mounts the back to corners, and the axle/control arms mounting point the front corners.

As the one tire drops, the one control arm effectively becomes shorter and the whole square is trying to deform. The fact that the control arm has two mounting points on the front is what is causing the binding. If you remove one, then it is free to move more. Hence the reason why a three link will free up the front to move.

Good testing though.
 
ToolsRUs - I get what you mean about "ease" of flex, makes sense. The weight of the truck in real world situations probably would make that something to make sure was done. I'm pretty sure I'm pulling the arms off again soon so I'll make that change.

LCPhil - I have Christo's weld-in adjustable link which is slathered in enough grease to let it rotate freely as the front articulates.

Christo - I figured you'd know all about this ;) The thing that I noticed and is hard to describe to folks without several 3-D diagrams is that the "box" formed by the frame, control arms and axle isn't square at all so the arms never really have all three bushings moving through a parallel plane. So the frame mount and the rear axle one can rotate on the joint the Outback arms have in that section but the front axle mount, as it drops or raises to full extent, is now trying to rotate in an oblique plane to the other two. Hence it binds up on the front axle mount plates and functions to stop everything from moving further.

ToolsRUs had recommended grinding the bushing mount ring on the front, especially on the top half so it was narrower and could rotate more in the axle bracket. This made sense and I planned on taking the arms off and milling the top edges off. Then after looking at those pics and thinking about it I had this idea. Obviously it is a bit different for my use since I have the caster set up but in a typical setup the front most axle bracket retains the standard gap where the bolt passes through but has flared sides to match the rotational movement of the front bushing. Yes, No, Maybe????
bracket mod.webp
 
Thanks for this great write up!! Very informative. I just installed Slee's 6" kit on my rig (which is a great kit by the way. as if you all didn't already know that.) And when I saw your arms, and Landcruiserphil's shocks I started to get those thoughts of upgrading already. It's great to here that running the L's isn't really going to hurt the travil...however the Bilstein 7100's might find there way on at some point, they have moved way down my list. Also Christo's front arms are a work of art and now I don't feel bad at all that I don't have the rotating joint of the Safari's that I was just sure was going to make a huge difference. And once again you do have great write ups!!! I thought Christo's post about the real vs. symulated settings was interesting. My first thought was you might be getting more flex out of a ramp due to the tires moving rather than dragging on the asphalt causing resistance to movement. However, he has the most experience with it and seems to say they are the same. (ramp vs. forklift)
Anyway
thanks
 
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