Alignment, Caster, Clearance, and Driving Report with Light Racing UCAs

Seems like i have spread this into a couple random SPC threads.
May as well jam it in here too.

The T4R 3rd gen guys were/are running a 'G' (forward) setting to clear the body mount/rear fender.
Had me scratching my head as it was reducing actual caster numbers.
I had thought more caster helped to clear the rearward rubbing area...not so.
I just did this to help myself understand whats going on, maybe it will assist others.

That balljoint seems to get installed 180* backwards a bit too, watch out for that.
3 backwards pics.

 

Ok, so trying not to confuse myself with this... but what are their final alignment numbers to avoid rubbing?

I’m all for moving things around before my next alignment but there’s too much conflicting info... My UCA balljoints are set at D (+2°) now, with the lowers almost maxed for caster and I got right around +3° of caster on my last alignment sheet.

I have little to no rubbing on the cab mount right now but I’d like to try to find a way to set the UCAs before I go in for my next alignment that would allow the tech to only touch the lowers and hopefully leave them in more of a “centered” position to avoid unnecessary stress on the bushings. But I’m starting to think that’s not going to be possible if I want to avoid a CMC...

 

Great info, i've been trying to correct this as much as i see it around as well. A lot of posts seem to indicate more caster = more clearance while that may be true with other uca's that's not really the case with SPC ucas since you can lower the caster up top to push the wheel farther forward.

in my case i havn't gotten a professional alignment yet and not sure if i ever will. I'm running lower control arms completely maxxed for caster, rear cams maxed out, front cams maxed in and my spc in position D. I'm running -25mm offset SPC 16x8 F5's thats 3.5bs with 285/75/16 (33's) i had plenty of clearance from touching the cab mount chop with no CMC for street driving. I did have to trim the front and rear fender, and heat gun remolded the front plastic wheel well. I did a CMC and pinch weld hammer as it looked like it would barely rub once i started to do some offroading and plan to maybe eventually run a larger tire. For now tho I've got 0 rubbing after addressing the spots where it was rubbing.

Spent a lot of time self aligning and got it pretty much dialed in and driving straight. I may eventually take it in, but don't really trust any alignment shops around here to work with this custom setup.

 

So many variables, wheels, tires the particular vehicle. Also personal driver sensation.
Generally the 3rd gen 4runners seems to be getting about 1.5* to 2.5* caster on the G setting... one guy said he got 3* caster.
This was to clear the body/cab mount with tires over 33", more so the 35"+ guys.

I personally like the higher caster numbers, i am just shy of 5* caster (D setting), steering is a tad on the heavy side but this T4R tracks like an arrow now. No wandering sensation like i had at 2.7* caster.

Now i am sort of wondering if high caster is bad for the rack and pinion, if it has to work harder to fight the added caster? Burn up the steering rack?

 

I don’t like the way my steering wheel reacts to bumps right now, I can tell you that much... and it did not feel that way on the stock UCAs. And I’m afraid if I go any higher on my caster numbers I’ll have to cut even more out of the front bumper/wheel well to avoid rubbing. I already had to trim that area a ton to fit the 285/70/17s.

That’s one of the main reasons I want to play around with my alignment settings. I just don’t know which way to go first... do I add more caster up top to try to get the lower cams more centered, do I drop it to G and fully max the lowers or do I stick with the D setting and just have the tech tweak the lowers to get everything dialed in?

Either way, I’m going to wait until I get my new wheels installed before I change anything since they have a more aggressive offset than my current setup and will change where any potential rubbing will occur. I’m just still really confused about the best approach for avoiding rubbing the cab mount and the best steering wheel feel.

 

If you set it to G you will have less caster adjustment and move the top of the tire into the front bumper more.
I have stuffed a tire into the front bumper on this D setting, bent the little front lower wing on my Shrockworks...

The less caster you have the more the road surface will try and move the steering wheel around.

 

Moving the top of the tire would work, I just don’t want the bottom any closer to the front.

Maybe I’ll try the setting in between D and G and see how that goes. I’ll just need to get a lifetime alignment package so I can play around with it and have the techs just tweak things to get the camber/toe right.

 

I’ve read and read but couldn’t find a clear answer.

What is the preferred ball joint orientation? I installed mine today in neutral. I will have 35s on tomorrow and may play with the settings. My main concern is pushing the tire forward, not increasing caster. I already set my lowers properly.

I’ve always had high caster numbers (~4-4.7), don’t know the difference in driving experience with lower caster.

 

I have 285s, but I set my SPCs at “D”. It pushed them about 1” further forward after the total alignment was finished. My caster is now at 4.1 and 4.3 I think. Before with Icon non-adjustable my caster was both around 2.5 or so. It drives much better with higher caster.

 

Just to give some insight to people, I left my cam tabs on position E. Super annoyed with how it tracks on the freeway. I only achieved 1.8 and 2.1 caster. Lowers maxed out.

Will be moving the ball joints to position D tomorrow and pushing for some higher caster numbers.

 

Any new insight? I hate the jerky steering wheel over bumps. Im on detting F, caster at 2.4 and 2.8, 0, and 1/32.

 

Update

Moved from E to D. Super happy with how D drives, truck feels more stable at higher speeds and more like my old truck. I set caster and camber, only minor adjustments were made on the rack (5 minutes worth, tops).

Caster: 2.4 and 3.0
Camber: .4 and .2
Toe: In spec

 

Nope... only insight I can provide is that my power steering rack is shot, which might be part of the reason my steering has felt so crappy. I’ve got leaks on both ends of the rack and will be swapping it out (and adding energy suspension poly bushings) before I mess with the alignment.

 

What are the best numbers for alignment? I hear set castor to max or +3, then the toe and camber to spec. I did that and my tires still wore out fast.

I’m thinking Max castor to fit larger tires and set toe and camber to zero.

when at spec, for the 265 tire and zero lift the tire is pretty much flat on the ground. I maybe wrong but When I add 2.5” of lift and a 285 tire, the spec numbers (camber) increase because the angle is increased due to the increase distance from the lager tire.


I’m not geometry major, just a grunt. But this is my point. Stock is fine if I didn’t adjust the ride height.

Throw me a bone someone

 

Not sure what you are asking.
0-3 inch lift as long as your alignment is good your tires should sit flat on the ground.
If not you may have more camber than you want.

 

yeah I thinking to much into it.. 0 cam 0 toe.. stock kills tires

 

Question: I curretly have cmc and castor set at 3 with spc. Planning to run 35's soon and want to set caster from LCA further out. What are the cons of setting castor past 3? Some say it'll ride like sh*t?

 

Myself and others are pushing 5* caster or more.
All the caster will effect is the way the steering wheel returns to center.
I got sick of endlessly steering just to keep the 4runner tracking straight down the highway.

Not sure how caster can change how the rig rides.
Tires, air pressure, shocks and springs will effect the ride quality.

 

Sub’d for great info!

 

Here's one I didn't see in this thread yet. Put my SPC's on over the weekend. Just got back from a highly recommended alignment shop and found my ball joint settings were asymmetric. Being OCD, this bothers me, but the truck drove great both on the highway and through my neighborhood. My caster came out to 3.5/4.0 and It seems the rubbing from my 285/75/16s is gone. Both of my LCAs are definitely set full forward caster (rear 100% out, front 100% in). Driver side at "C" position while passenger at "D." Maybe the infamous taco lean is causing this issue? Anybody else have an issue with this? I've already called SPC tech hotline and they say it is perfectly normal. One setting off from each other is ok....

Side question: My alignment report reads caster values at 20 degree wheel turn, is that what most other people on this thread are reporting to? My tech mentioned something about Toyota uses 15 degree to get their measurements.