Panhard/Draglink Relation

Would the plates for the double shear arm be made from mild steel or chromoly plate? 75/25 gas?
Sorry to get off topic I've tried looking for info online about this and I haven't found much.

 

You can weld 4130 to mild steel if you want. 75/25 should be fine. 98/2 could provide better shielding on thicker materials but if I already had the 75/25 I would end up using that. If it were tig 100% argon is fine.

 

So reviving this thread. Similar issue as op. Superduty axle. Draglink measures 46.5 eye to eye and panhard is 41. 5.5” difference and panhard is currently a 1.5 degree difference from the draglink. I am going to adjust the panhard to be as close to the same degrees and believe I can get it to 0 or within 1 degree.

how much bump steer can I expect with a 5.5 in difference though? Everyone says the degrees is important and to keep them flat which they are close but the 5.5 in length difference worries me since my personal truck is within a degree and within an inch. But my truck also uses an inside the frame steering box vs the outside the frame Toyota box in this other truck.

 

@malburg114

I built my truck (frame/suspension) in SolidWorks before I started actually building it. I messed around with a few relationships with the draglink/panhard trying to minimize my bumpsteer. So in my modeling I found as the suspension droops, the pinion angle increases (obviously this depends on how you setup your upperlink/lowerlink length ratio), and the axle mount for the draglink creates a slightly larger travel arc than the axle mount for the panhard bar. So in order to minimize bumpsteer it is better to have the draglink slightly longer than the panhard bar. For my application, I found making my draglink 2.25” longer than my panhard (my upperlink is 84% the length of my lowerlinks) my bumpsteer is practically zero. The smaller your upperlink/lowerlink ratio (to where your pinion angle won’t change much throughout travel), the closer your draglink/panhard need to be in length. If your upperlink/lower links are the same length, then your pinion angle changes more, and I’d shoot to make the draglink maybe 2.5”-3” longer than the panhard bar. This is an oversimplification, there’s obviously a ton of variables and unless you model your exact setup you won’t know what is the most optimal. Hope that all makes sense.

5.5” difference is quite a bit. You will have some bump steer (I can’t tell you how much or how good/bad it will be), I’d say just try to make sure your pinion angle points higher as it droops, lengthening the upper link will help.

Another option is to do an inverted-T steering setup.

 

Thanks. So after lots of research and hooking up the steering shaft and putting a camera to watch the steering wheel and a few hours of cycling, I found there is next to no bump steer. And this is with the frame side panhard still high 1.5 degrees compared to the drag link. The only time I see bumpsteer is when the axle is fully articulated (one side up, one side down) and it’s very minimal. Steering wheel maybe moved a 1/16 of a turn. It’s barely enough for me to see at the pitman arm/knuckle. I cycled it several different ways and main thing I was concerned about was at ride height and 2 inches up and 2 inches down from ride height and there is none there so that’s good.

good to know about the lower/upper link percentage and how it affects it. I forget the percentage it is now and I haven’t finalized the pinion angle so that’ll help more.