6112/5160 and AAL… bumpstop challenge

New numbers with angles against true horizontal. Bumping up against uncertainties a little. If you figure the shift, I’m within about 0.2 degrees for the working angles compared to zeroing on the output flange.

 

Didn't change a whole lot.
I was curious why the 1st working angle is so far off.
A cb spacer is going to be the easiest way to try and correct it.
A shim is probably the better way.
1 deg of shim per every inch of lift is a good rule of thumb.

 

Yeah, a little stumped on why the first working angle is so high. Going to put some more miles on it and reassess in another few weeks or month.

A CB drop is going to make the first angle worse, while lowering the second and third angles. And a shim is probably going to add 1/4”+ lift to the rear. Kind of damned if you do sort of solution.

 

I didn't measure before lifting and my truck had a shim when I bought it. (2yrs used)
2.5" front. 1.5" rear and these were my measurements with only the 'stock' shim?
I added a cb spacer at one point just to see. It brought the angles closer to 0 but created that 30mph vibe so I took it out.
1st angle is 0.4 (0.5 degree.)
2nd and 3rd are mostly equal and less than 3deg so I left it at that.
Drives fine.

 

Well, I went out and bought a small carpentry square to make sure I’m getting plumb measurements off the surfaces.

Here’s a before and after I put in 3/8-1/2” of CB drop with some washers. I still don’t understand that high first working angle (yes, CB makes it a little worse). That’s something that seems pretty high to start with. Still have some vibration after the CB drop, it I’ll drive it for a few days to get a sense of how it’s changed. I could probably get 2-3 degrees of axle shim in there and reduce the overall angles, but that’s more lift.



I also took some measurements for what the resulting lift was. I’m about an inc( over what I was hoping for.

Front R/L: 2 3/16”, 2 5/16”
Rear R/L: 2 5/16”, 2 7/16”

Distance from the ground on 45k miles of 265/75/16s. This was measured with a laser for consistency.

Front R/L: 36 11/16”, 36 9/16”
Rear R/L: 38 3/16”, 38 4/16”

Calculated rake.
Rake R/L: 1 8/16”, 1 11/16”

I’m not sure what the stock rake is out of the factory, But I’m sure I’d lost a fair amount of it. I think I recall stock rake being about 1”?

 

Alignment done recently with Tandem Offroad.

 

Sure would have been nice if caster was at the higher end.

 

Yep… they sort of said: “Three letters bro, UCA”. They were pretty sure I could get in spec with some aftermarket control arms. I’ll hold off on that for a bit. It all adds up. . Front end is just a bit more twitchy, but still completely tolerable.

Now I’m debating 33’s in the summer, repeating my 265/75/16, or moving to 235/85/16.

 

Update: I finally got around to installing my 3 degree shims and it completely removed my vibes. They had lessened a little bit over the months, but were still noticeable. Now I think it’s only my tires that are starting to show their age. Otherwise, pretty smooth. I still have a few washers above the carrier bearing. It’s 98 feeling like 104 out there today so I’ll find a cloudy day to do the measurements again.