Control Arms - Horizontal separation at the frame & axle

[Herzog]

Let's talk Horizontal separation of control arms, since vertical has been beat to death.

What are your experiences with having the arms as far outward on the axle as possible on the front/rear? How about at the frame side? Have you tried variations and noticed any differences? Any math geeks out there run numbers on these scenarios?

My last rig had the lower arms placed at about the same width as the frame at the axle side (so there was quite a bit of axle tube before the wheel, if that makes sense). The rig road very nicely but I had a good amount of body roll (I never had anti-swaybars).

My current rig has the arms out as far as I could thinking this would help with stability and also prevent damage to the axle housing if it were to take a good bounce on the tire/wheel. So far I've noticed that the stability part is quite true, still no swaybar and I have no issues with sway... The downside is that I feel like I can feel more of the terrain through the chassis as my arms have to move more (asynchronously) to soak up the bumps.

Anybody have any experience in this? Is there an optimum zone?

 

[skippy]

I have a theory but I think I will wait for Carl to answer this and then then just copy him...

 

[Herzog]

I have a theory but I think I will wait for Carl to answer this and then then just copy him...

That's what I do too. But it would be good to hear what you think. I don't think it's a well covered topic but it is important.

 

[SWALLDOG]

Are you talking just lowers or uppers also?
This is how I have built most of the setups I've done and my thought process. space and clearance kind of take priority but I like to keep them as wide as I can if they are not triangulated. On the frame side on the lowers I don't like to go past the frame, usually underneath or frenched in to the frame. And then on the axle side I will get them as wide as possible before the tires hit at full lock. I think the more axle tube is sticking out past the link the more leverage the axle/tire has on the suspension. I want it to be as strong as possible. Also with the link close to the tire, it will travel with the tire. Like when the tire goes up and over a rock it will bring that end of the link up with it, higher that if it was farther down the axle.

Probably at work under a truck.

 

[Herzog]

Are you talking just lowers or uppers also?
This is how I have built most of the setups I've done and my thought process. space and clearance kind of take priority but I like to keep them as wide as I can if they are not triangulated. On the frame side on the lowers I don't like to go past the frame, usually underneath or frenched in to the frame. And then on the axle side I will get them as wide as possible before the tires hit at full lock. I think the more axle tube is sticking out past the link the more leverage the axle/tire has on the suspension. I want it to be as strong as possible. Also with the link close to the tire, it will travel with the tire. Like when the tire goes up and over a rock it will bring that end of the link up with it, higher that if it was farther down the axle.

Probably at work under a truck.

Yes both.
I think we are on the same track. That's the same reason I did my current setup out wide. I also figured that having the upper arms (which are triangulated on my setup) out as far as possible on the frame side and also a little more outward than normal at the axle side so as long as the triangulation still works. It does feel very stable, I really like it.

Old - a lot of leverage! I think the only reason it didn't bend was due to the sleeve.


New Lower axle side:

New Upper axle side:


Here are the best photos I have of my current rear setup: