SPC UCA Settings With 33's

[alexperrucci]

Just curious what UCA settings most people are using with 33's + wheels specs and if you have any issues with rubbing.

Im rocking 333fab cam eliminators, rears outboard, fronts center, think when I initially installed everything I set the SPC's at E as recommended by a few on this forum but when I got the truck aligned the shop put the arms to the "stock" neutral setting. Alignment is great and the truck drives awesome besides some pinch weld rubbing at full lock, mostly in reverse, and some over big bumps.

Wheels were stock 5 stars 16x7 w/ a 1.5" spacer for an effective offset of -23, 285/75's. Now with the new wheels 16x8 +0 still with the spacer we're around -38 offset so obviously the rub is worse now. Most likely stepping down to a 1" spacer so the wheels will be 16x8 -25.

So just curious what everyone else is running and if this amount of rub is normal or if I should think about having the truck realigned with different UCA settings. I'll drop some pics below of how much I've done so far to try and mitigate rubbing.

Thanks!

 

[Zhehan]

I have the JBA High Caster arms and my alignment cams are set to the rears fully out with the fronts at or near neutral. I have 16x8" wheels, 0 offset, 4.5 backspacing and no rubbing. Octanejunkie has the same arms as you, with the Camber/Caster offset in the "E" position like you, he also has cam eliminators and his alignment adjustment is set like mine. You should get yours re-done.

EDIT: Do you know what your Caster is? It should be +3.5*. I bet the alignment guys set is to the stock settings.

 

[alexperrucci]

Not sure what my alignment specs are currently, don't have the sheet.

My arms are definitely set to "D" right now though, I think I installed them at "E" and the shop put them back to "D".

 

[Zhehan]

I glossed over the comment about the shop changing your settings. My bad. I would find another shop that works on lifted Toyotas on the regular if you can find one and they can get you sorted. Or, you could set the arms and cams to the way the way they should be and just tell the shop to adjust toe and be done with it.

 

[alexperrucci]

Honestly after looking at the SPC alignment settings sheet I don't understand why alot of people run them at "E". From my understanding it seems like you would want them at "B" or "C" for more positive caster.

 

[Bad Luck]

Honestly after looking at the SPC alignment settings sheet I don't understand why alot of people run them at "E". From my understanding it seems like you would want them at "B" or "C" for more positive caster.

If you were to leave the lower control arm adjusters centered then yes you would want to use A/B/C to get more positive caster, but by adjusting the front adjuster all the way in and the rear adjuster neutral (or out) that causes more positive caster. If you were to combine that with A/B/C you would have way too much caster.

Also, the purpose behind adjusting the front adjuster inboard and the rear adjuster outboard/centered is it moves the tire forward in the wheel well and further away from the pinch weld.

EDIT: Too much caster makes it more difficult to turn the steering wheel. The more positive caster a vehicle has, the more it wants to return the steering wheel/tires to straight ahead, and the more force is required to overcome that to turn.

 

[Zhehan]

From what I've seen, they recommend that setting because it allows you to get tire clearance by using the cams to move the tire forward in the well. Since the SPC arms also allow you to adjust Camber, you have more options with the lower cams. Maybe give SPC a shout to see what setting they recommend for your truck. Communicate this to the Alignment techs.

The JBA arms have a fixed +3* of Caster in the design, but no additional Camber adjustability. I have good clearance because of the rear cams being pushed all the way out which moves the wheel forward and widens the track a bit as well. It is much better than it was with the stock arms, plus the additional Caster improves on and off road handling.

 

[alexperrucci]

Understood! Thanks for the replies.

Can the tire be moved forward by just adjusting the upper control arm or is it mostly done with the lower?

My lowers are set outboard rears but fronts center, wishing I would have set the fronts inboard now as well. They were kind of a ***** to get in and I'm assuming adjusting them won't be super easy either.

 

[2021nightshade4x4]

The world changed when I went from +2.5 to +3.0. Went from thinking about selling for an LX to not regretting my purchase.


Sent from my iPhone using Tapatalk

 

[Bad Luck]

Understood! Thanks for the replies.

Can the tire be moved forward by just adjusting the upper control arm or is it mostly done with the lower?

My lowers are set outboard rears but fronts center, wishing I would have set the fronts inboard now as well. They were kind of a ***** to get in and I'm assuming adjusting them won't be super easy either.

Mostly done with the lower control arm adjustment since the hub is offset on the steering knuckle towards the lower control arm. I'm not sure how else to explain it so if you need a visual aid look at this photo and note how much closer the hub is to the LBJ vs the UBJ: https://www.toyota-4runner.org/3523017-post14.html

 

[alexperrucci]

Mostly done with the lower control arm adjustment since the hub is offset on the steering knuckle towards the lower control arm. I'm not sure how else to explain it so if you need a visual aid look at this photo and note how much closer the hub is to the LBJ vs the UBJ: https://www.toyota-4runner.org/3523017-post14.html

Got it, yeah that makes complete sense.

Will probably get under the truck this weekend or next and see if I can get some more out of the LCA and get re-aligned.

 

[162435]

Got it, yeah that makes complete sense.

Will probably get under the truck this weekend or next and see if I can get some more out of the LCA and get re-aligned.

Any update on this? I'm considering a change to 285/75 from my current 265/75. My truck drives great on its current (recent) alignment - I set it up with the SPC arms on "D", the lower rears all the way out, and the fronts all the way in.
The truck is on a full Dobinsons IMS lift with at least 2.5" up front, stock wheels, 1.25" BORA spacers, and the small SR5 fender trims.


Andreas

 

[alexperrucci]

Any update on this? I'm considering a change to 285/75 from my current 265/75. My truck drives great on its current (recent) alignment - I set it up with the SPC arms on "D", the lower rears all the way out, and the fronts all the way in.
The truck is on a full Dobinsons IMS lift with at least 2.5" up front, stock wheels, 1.25" BORA spacers, and the small SR5 fender trims.


Andreas

I haven't had time to mess with it yet honestly haha. I would guess you'd be fine with those settings though.

 

[alexperrucci]

Finally messed with this when I rebuilt my front suspension. Rears of lca are now all the way out, fronts all the way in, SPC's set at neutral setting. Now have plenty of room for the tire and no more rubbing!

 

[96RedRunner]

https://www.toyota-4runner.org/3rd-...l#:~:text=Toyota LCA bushings,Attached Images
https://www.toyota-4runner.org/atta...7904328-spc-uca-alignment-sheets-img_0808-jpg
Been rolling on this since late Oct. Rear cam out front cam used to set caster.
3" clearance only rubbing I've had been when reversing wheel turned certain way on uneven ground.