Alignment journey

[Torkman66]

There are others with more knowledge that will help here. However, your numbers are very close to mine. I would absolutely NOT put in eccentrics to chase that minor caster diff. They will effect camber. That caster diff is not causing any issue. The drivability you say is good. Leave it. It will always have a bit of a truck feel, cause it’s a truck. I would however make a slight adjustment to your toe. Total should be close to .25”. I would make a simple adjustment left and right to get tow close. Then leave it and enjoy.

 

[DirtDonk]

I suppose it could. Can't imagine it would be by as much as you're seeing (1.8 degrees) but any time you mess with the pivoting points themselves (the ball joints) it can conceivably effect the SAI.
It's not the same as camber of course, but if you changed the camber with the eccentrics, you moved the pivot points and that would possibly mess with the SAI.
Even if, as in your case, the eccentrics were used in their forward and rearward settings, changing caster angles, that change could still mess slightly with the SAI I would think.

What about the cut and turn? Thinking along those lines, when you cut and turned the yokes, did you have to do one much farther than the other?
Because caster angle would skew the SAI angle slightly.
Perhaps the combination of cut-n-turn AND eccentrics is what you're seeing in the SAI discrepancy.
Any idea what is it supposed to be? Are they supposed to be equal, or is there an expected cross-sai specification? If so, I've never seen it mentioned.

Paul

 

[DirtDonk]

I would absolutely NOT put in eccentrics to chase that minor caster diff. They will effect camber.

They can only effect camber if you adjust them in such a way as they tilt in or out. But if they are angled all the way forward or rearward, they should not have any effect at all on camber.
That said, if I had them in there, at an indicated 8 degrees, I would certainly not be using them for caster correction!
Instead, I'd try to turn them to reduce some of that camber. I know it's within spec, but I'd pull some of that out and get it down to less than 1 degree per side.

I would however make a slight adjustment to your toe. Total should be close to .25”. I would make a simple adjustment left and right to get tow close. Then leave it and enjoy.

That readout is listed in degrees, not fractions of an inch. A 1/4" is usually the maximum recommended setting, but we have to convert degrees to inches, based on the overall diameter of the tires in use.
Absolutely play around with toe-in though. It's easy, cheap (free usually) and can sometimes make a huge difference in driving feel.

Paul

 

[Torkman66]

That readout is listed in degrees, not fractions of an inch. A 1/4" is usually the maximum recommended setting, but we have to convert degrees to inches, based on the overall diameter of the tires in use.

You are correct. I failed to look close. I would still adjust that toe a bit.

 

[DirtDonk]

Me too. I've seen some surprisingly spectacular results from just a little driveway tweaking of toe-in.

Paul

 

[73azbronco]

Wow I've only got just over 3 deg caster and mine drives pretty good... I run 25psi KO3's at 35 inches.

 

[Torkman66]

Wow I've only got just over 3 deg caster and mine drives pretty good... I run 25psi KO3's at 35 inches.

Yea, I just don't get it. I'm only at a 2.5" SL, 33 KOs, and I require 8* caster to make it drivable. After the initial rebuild, 7* wedges, and even 1.5* eccentrics, my alignment showed 4.3* caster. That should have been plenty for a good ride, but it was a scary ride. So, I started looking at everything else. Lowered the trac bar and pitman arm, triple checked geometry, ensured BJs were installed right. Re-balanced the wheels. Installed stab bar. Tried various tire pressures. Messed with toe in. Front end 100% new parts left to right and new from steering wheel down to the ground. But until I got to 8* caster (adjustable T-Rex), she whipped all over the road to the point it was not fun to drive. Even if I would have cut and turned the Cs, ( I should have) I would still have ended up at the same place in terms of required caster (but with a better pinion angle). So go figure...

 

[73azbronco]

25psi maybe? I tried 33psi, all over the place.

 

[JAF]

Thanks for all the advice guys....added a 1/16" to the toe-in. Also added a hellwig front sway bar. Gotta say it drives pretty good. I think now I'll just put some miles on it...

 

[Torkman66]

Thanks for all the advice guys....added a 1/16" to the toe-in. Also added a hellwig front sway bar. Gotta say it drives pretty good. I think now I'll just put some miles on it...

Gald your happy with the results. I also put on the Hellwig bar...definitely helped with roll rate when turning. Overall, everything you have done is probably the best you will get. It's a truck, it will always drive like a truck. Key for me (and you) is that it must be safe and not whipping all over the road. I'm certain this thread will help others in that this is a common challenge.