LCA bushings, adjustment cams and wear at extreme settings

I have a question about the LCA bushings i cant seem to find a concrete answer searching on. Recently added a moderate lift and was trying out different caster settings on the SPC UCA. To optimize the suspension travel, i was adjusting the LCA cams to center the tire in the wheel well at full articulation for clearance and to eliminate rub. I'm only running a 32" tire on a 0ET wheel so nothing extreme, no CMC or other trimming other than removed mud flaps.

When adjusting the LCA cams to extreme opposite settings to add caster, does that have any negative effect on their lifespan? Seems that the arm is very twisted like that and may bind a bit under movement, no?

For example, when i put the SPC UCA in pos D which adds 2deg caster over stock, i found i needed to adjust the LCA cams to opposite extremes to push the tire full forward so it would not rub at the rear. This put me at a resultant 4 deg which rode super nice but had me concerned about LCA bushing wear with how twisted the LCA would be. You can see how one cam is pushing full inward and the other is pushing mostly outward. Another side effect of this is the tie rod ends had to be spun almost all the way inward to zero out the toe and the SPC UCA camber slider almost ran out of adjustment full inboard to zero camber since the wheel was getting also sucked inward. For many reasons, this didn't seem like an ideal overall configuration so i went to try another setting. No wonder people have to do a CMC with 33's even with modest caster correction!



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I then switched to setting E on the UCA, pulled the coilover and went to reset the LCA settings again. At this position, i was able to get the LCA cams, the tie rod ends and the UCA camber slider in a much more neutral setting while still having enough tire clearance in the well at full compression. This setting only supplies 1 degree of added caster but with some very slight adjustment of the cams, i was able to net 2 degrees total which seems to drive fine. You can see below that one cam is completely neutral and the other is slightly pulling inward to add some caster. Tie rod has plenty of thread and the UCA camber is like midway in the slider so lots of adjustment leftover. Seems a lot less twisted overall and less likely to wear prematurely if thats a thing.



Seems like the SPC arms could use a setting between D and E that might be able to add 1.5 degrees to net somewhere around 3 degrees total caster. You may need to tweak the LCA's a little more but would be a better compromise vs the D setting.

 

When you have larger tires, it matters more where caster adjustment is done, (LCA vs UCA).
Add caster via UCA moves tire back closer to body mount where tire is more likely to rub. Add caster via LCA moves tire forward where it is easier to move plastic liner to avoid tire rub.
I maxed the LCA cams to get the most caster on my 4Runner. Theoretically it may stress bushing material more but I haven't had issue from it so far. Been at least 40,000 miles since I maxed those cams. No visible tears or performance loss.

 

You're overthinking this. The rubber LCA bushings are more than capable of absorbing any slight angle of the control arm because the arm adjusters are maxed one way or the other. Set your caster so that your tires don't rub and the truck tracks straight, then go drive it.