Hoping for some interpretation of alignment numbers, with the JBA high caster UCAs, and a ~2" Dobinson's spring lift. Today I finally went in for an alignment, and here are the numbers:



Looking at the "after" numbers, they look pretty decent, toe and camber are in spec, and caster is a little high but not unexpected with the JBA UCAs.

But, the cross camber is out of spec, and the SAI and Cross SAI are way out of spec.

The service manager said they "did all they could" to bring the numbers in spec, but couldn't do it. I watched the tech from afar, and tried to communicate with him, but his English was almost nonexistent, so that was a lost cause. From afar, I didn't see him working on the LCAs too much if at all, but I might have missed it. Overall though, this is definitely not a high-end alignment shop.

Here is how the cams are currently positioned:





I'm not sure what to do with this. Can I make some adjustments to get the cross camber closer to spec, and then go back for another alignment? I also don't know what the SAI numbers mean. Why are they so high, and why did they change between the first two alignments, when I don't think I changed anything in the truck?

One more thing, the truck has driven great with all these alignments, I never had any pulling, wandering, or failure to center.

I'm probably going to end up going to a high end alignment shop, but before I do, I'd like to understand better the meaning of these results.

Some more background and earlier results, which may not be relevant.

I came in for alignment on 11/25/19, with OEM UCAs, and brand new LCA bushings, KYB shocks, and a 1/2" spacer lift:



Caster was a bit low (not surprising for a lifted truck), but everything else was in spec.

I went back again on 1/15/21 because I added 5th Gen 4Runner rear springs, but still with OEM UCAs, KYB shocks, and 1/2" spacer lift:



Caster was now in spec, but the SAI numbers (18.5*) were now way out of spec. I realize now that I didn't even notice the SAI numbers, I just focused on toe, camber, and caster.

But maybe the SAI numbers became high because they adjusted the caster to bring that in spec (given the lift), which threw the SAI numbers out of whack (the caster was not in spec on the previous alignment, which is probably why the SAI angles were fine)

I’m going to do my best to explain SAI but I’m not very good at putting things in layman’s terms.

SAI is Steering Angle Inclination. If you were to draw a line from the upper ball joint through the lower ball joint and end that line at the ground that is your steering axis.. The angle formed by a vertical line and the steering axis is the SAI. In a stock suspension vehicle a bad SAI can indicate a bent suspension component (upper/lower control arm) or frame/mount. The SAI specification isn’t going to apply to lifted vehicles. Because you have raised your ride height you have now changed the locations of the upper and lower ball joints (the steering axis) in relation to where they were. They have moved down and inward because the control arms move each ball joint in an arc. The upper and lower control arms are different lengths so the arcs are different. As an example the lower control arm moves the lower ball joint 2 inches down and .5 inches inward toward the centerline of the vehicle and the upper control arm moves the upper ball joint 2 inches down and .25 inches toward the vehicle centerline this causing the SAI to change. (These figures are not exact, but it is accurate that the upper control arm and lower control arm move the ball joints inward in different amounts for the same vertical movement.)

TLDR: SAI (steering angle inclination) is going to be different and more out of spec the further you get from factory ride height and factory suspension geometry. If you are lifted don’t worry about it.

Higher caster helps with steering wheel return to center and not wandering when going straight but steering effort will be increased when turning. Uneven caster (cross caster) can cause a pull. Uneven camber (cross camber) can cause a pull. Some manufacturers have slightly different left/right camber/caster to account for road crown. (Most roads are not perfectly flat to allow water to drain off easier. Typically the double yellow is the highest point in the road and it tapers in elevation towards the white lines/shoulder.)

Performing an alignment is an educated guessing game. Once you have your starting/current measurements and the manufacturer specifications then you start with camber/caster. Unless you have a special upper/lower control arm all camber/caster adjustments are made with the two eccentric cams on each lower control arm. When you rotate one of those cams you are changing BOTH camber and caster simultaneously, which is the tricky part because most alignment machines do not show you real time caster changes. You have to guess your adjustments and then perform the caster measuring procedure again. It can take a very long time to get the camber and caster correct. After camber/caster is set then you set the toe and go.

Thanks @Bad Luck , that makes sense. So I won't worry about the SAI.

I'm thinking about what to do next.

I looked at the cams more closely, here is how they look (this is looking forward from the back) - I'm showing the photos and a cartoon of how I think the cams are positioned:



Then I took the standard (neutral position) view of the cams:



And over it, I superimposed my cam positions, along with my understanding of how the LCAs are located relative to neutral (neutral is black, mine is orange):



Here are my results again:



Sp looking at the results and the LCA adjustments, that certainly explains why the caster is high. I am guessing the tech who did the alignment before the JBA UCAs moved the rear cams out and front cams in to try to get the caster higher, but the tech who did my alignment yesterday, with the high caster UCAs, didn't bother to readjust the cams back in to reduce the caster. Totally consistent with my observation that he didn't do anything other than toe.

So if all this is correct, it seems like I can do several things:

1. Bring both rear cams in a little to reduce the caster from 3.9* to about 3-3.5*.
2. Increase the -0.5* camber on RH to about 0.1* (to match the LH) by bringing out both cams on RH side a little bit. Or alternately bring in both cams on the LH side.
3. Take it back for alignment to fine tune the camber/caster and toe in.

I realize that adjusting camber and caster is interrelated, which is why I'd take it back in afterwards. But at least I'd get it closer to where I think it should be.

Does that make sense?

I'm glad that helped and made sense!

1) Moving both rear cams in (meaning the lower control arm bolt moves toward the vehicle centerline) will reduce caster. If you want to try to keep the camber where it is then you can move the rear in a line or two and then move the front cam out the same amount.

2) To increase the camber you will need to bring the cams inward. (Negative camber is when the bottom of the wheel is further out than the top of the wheel. Think of those slammed/cambered ricer cars.)

Gotcha, thanks, I always get my camber backwards!

OK, so I'll reduce the caster a little by moving rear cams in and front cams out by same (small) amount (that will preserve the current camber).

Then I increase the camber (or "reduce the negative camber") on the right side by moving both front and rear cams inwards by same amount.

Right?

Another snip from the FSM to help you with all of this:



I do wonder how the tech adjusted the camber a bit, but then didn't go all the way to adjust the caster at the same time. It is Firestone though - they are rarely superstars with this stuff...

One thing to keep in mind - the extra caster using the lower arms is giving you more clearance at the back of the wheel well for tires. Reducing it back to the top of the factory range may cause tire rub. Make sure you have room to "give up" in that regard.

When I did my driveway eyeball alignment before going to the alignment shop, I started with 'max caster' (only 1.5" lift) and then brought the camber back to what looked like it was near 0. In your case, you want to start at 'mid caster' and then adjust for camber from there. Since the L and R cams are adjusted pretty similarly, you can rest assured that you likely have no bent components in the front...

-Charlie

Correct.

The only DIY way I can think of to see your camber change would be to get a magnetic angle gauge (something like this) and sticking it to a vertical part of the steering knuckle and zeroing it out. I've never tried it DIY so this is all "in theory". Make sure to jounce/bounce the vehicle a few times after each adjustment if you decide to try using the magnetic angle gauge.

Thanks for the chart Charlie, that'll help to know how much change to expect for each graduation.

I'm able to borrow a pretty nice AccuLevel alignment tool, so I can easily (and reasonably accurately) read out the camber directly.

And to your question about how/why the tech adjusted camber but didn't bother with caster - I actually saw him do that part, and he simply hit the tire with his fist to get the camber to move into "green" on his screen, I guess that was good enough for him . Like I said, I'm not sure he even knew what the cam bolts are for.

I get your point about decreasing caster leading to loss of clearance in the back of the tire, so I may just nudge it down a tiny bit and call it good.

I'm not the first to say this on these forums, but it seems that I've reached the point where I am basically using my lifetime Firestone alignment purely as a Hunter machine rental, to check the adjustments that *I* made, since I can't count on them to do the adjustments correctly. Pretty ironic.

I adjusted my camber settings by the amounts suggested by Charlie's chart, and confirmed by my AccuLevel. Will be bringing it back to Firestone this week to double check the angles, and to adjust the toe.

When I called them for the appointment, I understood why the tech never adjusted the cams on my last visit. The shop manager said that Firestone never adjusts camber or caster on lifted vehicles, and only works on toe. I tried to argue that there is no reason to not even try to adjust the camber/caster settings, but to no avail.

So I think we may be in for my tongue-in-cheek approach of making DIY adjustments at home, then bringing it in to Firestone to check the values more accurately. The joys of free lifetime alignments .

Try telling the manager they can either adjust camber/caster or you will schedule 10 alignment appointments in a day and do small adjustments in the parking lot between the appointments. He might be a little more willing to work with you lol You paid for lifetime alignments so no worries there lol

Exactly . Maybe they'll get the message when I schedule a repeat appointment before I even leave. Or better yet, maybe my DIY adjustments got me close enough on camber that all I'll need is toe adjustment.

Yeah, that sounds crazy. No such issues with mine. I guess a lot depends on the shop manager. I have also heard that some Firestones don't care for the lifetime if the vehicle is offroaded, but thankfully no issues here.

Here's an update - I had adjusted my camber to +0.2*, according to my AccuLevel, then went back to Firestone to have them double check the settings and fix the toe (my steering wheel was at a 30deg angle ).

The new tech (different from last time) asked why I was there just a week after the previous visit, and I said that the previous tech couldn't do the camber, so I did it myself. He found that very amusing, and put the truck on the rack. The camber measured at +0.2* on left side, and -0.2* on right side. The tech seemed very impressed, and announced that "the camber is in spec!". Yes, but not thanks to Firestone.

Here is the summary of my initial visit results, my adjustments, and the final results:



I'm not sure why my AccuLevel was dead on for one side (+0.2), but off by 0.4* on the other side (+0.2* vs -0.2*), but I was still pleased with the results. The caster was roughly the same as before, right around 4*. Also interesting to note how the SAI improved, and is now almost in spec.

I went back home and immediately double checked the camber with my AccuLevel. This time I got the same measurements as Firestone "after" readings, +0.1 on left side, and -0.1 on right side. I also noticed that camber can change by about 0.1* by as little as touching the tire, so I think I'm splitting hairs here. That was also supported by seeing that the new alignment has different camber numbers for before and after, and I KNOW the tech didn't touch the cams.

For anyone else reading this, I wanted to add some more info to Charlie's chart on how to adjust cams to change the camber and caster readings:



i stared at that chart for a long time and found it completely unintuitive on its own. So I went back one page in the FSM, and found the guideline for how to use the chart, which helped a lot:



So in my case, with my caster at 3.9*, and wanting to change right side camber from -0.2 to +0.2, I first plotted the "measured" value at 3.9 caster and -0.2 camber (red), then plotted the desired "standard" value at 3.9 caster and +0.2 camber (green), then drew the arrows in red to see how much the front cams and the rear cams need to move. In my case, both had to move by 4 graduations in the (-) (shorter) direction:



Here are before and after positions, with the roughly 4 graduation move:



So I created this picture to help others in the future, since it has both the chart and the decoder ring on how to use it:

I too struggle with $100 toe-and-go alignments. When you did yours with the acculevel, did you make the adjustments with weight on the wheels, or just take measurements with WoW and then lift the truck to adjust?

Also, did you use the wheel adapter kit or just the acculevel? If just the acculevel, how'd you rig it?

Haha, "$100 toe-and-go" - that's basically what it is!

I made the adjustments with the truck resting on the ground (one advantage of having a lifted truck).

I have the AccuLevel with the wheel mount Amazon.com: Longacre(R) 52-78298 Digital C/C Gauge, AccuLevel/QuickSet : Automotive., makes the process much easier -