Lift impact on thrust angle?

I have a 2023 ORP and have some questions regarding alignment and thrust angle.

I had the truck aligned from new at the dealer and thrust angle was -.13
I installed 6112/5100 a few thousand miles later for a 1" front and 0" rear lift and at that alignment the thrust angle was -.08
I installed b12 rear springs for a 1" rear lift, aligned again this week, and the thrust angle was -.29

That last measurement is concerning to me. Could the rear springs with 1" lift have caused it? Could it be an error in the alignment measurement? I don't think this is possible, but could the articulation of the rear axle to fit the new springs have shifted something back there?

Just trying to figure out if this is something I need to worry about and attend to, or if it is a non-issue to ignore.

Thank you for your thoughts!

 

It is due to the rear lift because of how the rear uses a panhard bar. The higher you go it shifts the axle more to one side. at 1" lift it probably is not so much an issue. higher than that it may affect handling a bit. That is why there are panhard correction kits. For me at 3" of lift initially I did not think anything but after adding the panhard correction kit it handled noticeably better. Mostly less squirrely in slippery conditions.

 

%^ this!!

I got this..... https://drkdss.com/collections/pan-hard-bar-bracket after installing my lift, quite some time later i added this to help with the shifting of the rear axle. It is very noticeable before and after. Like jdm said, less squirelly on road bumps and wet conditions.

 

Did either of you see a thrust angle change in your alignment as well?

 

How much of a lift did you have before you installed the bracket?

 

I wouldn't worry about it at 1" of lift. These brackets are meant to be used on 2-3"+ lift. If you overcorrect the panhard you will have thrust issues in the opposite direction.

 

That makes sense

 

Unless anybody knows the measurement error of the machines being used, I don’t think you could tell just by the numbers.

However, I would worry if something feels wrong while driving, for example if you feel it pulling to one side or another when you are accelerating/decelerating.

But there’s really not much that can change the thrust angle of the rear axle, because it’s fixed. Nothing is adjustable on it.

The panhard will move the axle slightly to one side or another during compression/extension of the suspension, which is normal. If you lift, then your axle will have a new resting position side-to-side, which might (?) impact the thrust angle measurement (I’m not sure). Panhard relocation only helps if you are feeling a subtle left/right motion during bumps that compress the suspension. This happens if the panhard is over center/not parallel to ground. But like has been already mentioned, a 1inch lift doesnt really necessitate one, and can actually create a problem where one didn’t exist.

 

Yeah, I was thinking about tolerances since the number keeps changing on each alignment. It drives well - better after this last alignment. I asked for a little more negative camber (-.3) and a bit more toe in (.05). I couldn’t get as much caster as I wanted and ended up at 2.8, but it tracks well and the wheel is straight.

It does make sense, however, that if the axle moves a little sideways it’ll also rotate a little. So getting some thrust angle out of a lift does make sense to me.

 

Sidebar to your situation…..

So you’re lifted 1” in the front and the alignment shop could only get 2.8 degrees of caster?

They should be able to get 3.8 at that lift height.

 

Yeah they told me they maxed out. Maybe I need a better alignment shop. This was with the dealer, which was perhaps a mistake.

Edit: or perhaps that was max they could get while hitting my camber and toe targets?