SPC A Arm Alignment adjustments for tire wear

[arich]

Getting some uneven wear on the out edge of the front tires.
I have a BP51 set and minimal lift and SPC upper control arms set at 0 degrees. The alignment is fresh but I'm getting excessive wear on the outside of the front KO2s. Pic one and two are the fronts, pic three is the rear. We're at about 5,000s and ready for a swap BUT my last pair did this and I don't like it. They should wear evenly across the tread and the last pair did not.
I know the print outs don't show it but I think the truck has Negative Caster. How can an alignment shop measure caster is they never turn the tires to the left and right? Is this what the computer "thinks" it has after proper Camber is set.
Your input would be greatly appreciated. This is beyond my pay grade.

 

[chilibit]

Even if your alignment is perfect you will likely get wear on the outer edges of the front tires owing to turning forces. You could bump up the pressures to compensate. Or rotate more frequently or periodically break the combo and remount the tires. Increasing pressures does not negate the wear---it merely relocates it. Now, if you are actually referring to 'cupping' when you say "uneven" that is a different animal altogether.

 

[BulletHead]

I just upgraded to SPC UCAs (preferred upgrade with OME 2" lift) and my numbers are very similar to yours Anthony.

I was wondering doesn't that caster need to be near 0 deg?

 

[Spudman]

I rotate mine at 10,000 kilometres every service, I've just put new tyres on, but the old ones all wore evenly with that rotation and I have a 2 inch lift, also got adjustable control arms as well.

 

[arich]

Still need help with tuning the SPC a arms

 

[TeCKis300]

What's your full wheel, tire, and suspension setup? You mentioned a mild lift, how much?
Do you drive particularly hard on pavement? Hard turns and canyon carving?

Your alignment looks okay. Perhaps a bit more toe than I personally like. That along with the relatively flat camber could account for some of the shoulder wear.

The other cause could definitely be too little positive caster. Such that when you turn the vehicle, there is not enough camber gain and the tire rolls over on its shoulder. I'd take a closer look at this first.

Lifting the vehicle too aggressively will in and of itself cause wear issues. The suspension operates in a region of its stroke that causes a lot of scrubbing and bump steer.

 

[Cruisin911]

With that alignment, I'd say its turning and scrubbing forces. 6k truck and big sidewall...... its going to happen. Every single AT tire I've owned on every single truck has done this to some degree.

 

[TimCFJ40]

All of my 4x4s have done this even stock. It's more obvious on an offroad tire with a difinitively squared corner like the KO2s. The only reason you don't see it stock is that stock tires have a more rounded corner profile that hides it better. Rotate the tires every 5k and you should get normal life out of them, but you'll never keep that square corner for the life of the tire.

 

[Sinister]

My KO2 have done this as well.

 

[arich]

Thanks for the replies guys. The BP51s are set to 0 preset so this nets me at a 3” raise over stock and about an inch in the rear for a neutral stance.
I have TRD “Rock Warrior” wheels, no spacers.
I don’t drive hard. I feel like the LC keeps me well behaved.
I called SPC yesterday and spoke with Tim in tech. He looked at the alignment and advise me to some negative camber. .5 degrees to be exact. I told me how to adjust the SPC arms if my lower adjustment cams were maxed out.
He thought the caster was fine.
I’m glad to hear I’m not the only one with this issue. My last set at 40k looked terribly worn on the outside shoulder and absolutely perfect on the inside.
I have to a Taco owner who gripped them around with whites out. (Not what I would have done).
Anyway I have an appt for an alignment adjustment up in Buchanan, NY at a great shop I always use. Then since the tire are so new I’ll put the worn shoulder on the inside and rotate to the rear a and ill report back.
While I’m at it I’ll get the guys to re powder coat the TRD rings.