Front camber and caster are only adjustable by shifting the front subframe. This means that side to side is not adjustable independent from each other. This is also something that 99% of Firestone like shops will not mess with. Having -1.5 up front is not very bad and Isn't going to cause abnormal tire wear.

 

So do I take from this that my alignment isn't that bad? Or are you saying that the camber/caster isn't my problem, it's the cross-caster? I really don't understand suspensions.

 

I agree that unless your toe is on the outside of the range, your wear should not be too bad with -1.4 camber. But this depends on a lot of other variables like pressure, wheel/tire combo, driving style, etc.

Also, if you are inclined to try to get it evened out, I had good results with the tyrolsport collars and new bolts to center the subframe.

 

Also, if you are inclined to try to get it evened out, I had good results with the tyrolsport collars and new bolts to center the subframe.

Say more...

What am I looking at in terms of parts/labor? What would you do if this was your car? (My goal is to avoid having my tires, especially if I replace them, getting worn down to nubs for any other reason than just normal wear/tear)

 

How are your tires wearing? Is it uneven, or are they just wearing evenly but quickly?

I don't know much about how all of these settings work together with regards to performance and tire wear, but here are some general observations:

Contact patch - the footprint of the tire on the road, ideally even across the width of the tire. Basically, you want it to be larger for more grip, but smaller for more fuel economy, so there is a happy medium to shoot for.

Camber - the angle formed by the wheel and the road surface. Because of weight transfer in cornering, the contact patch shape changes to be more of a pie shape with the wider end towards the outside. If you do a lot of hard cornering, this will wear out the outer edge of the tire. Having more negative camber (top of the wheel tilted in towards the car) helps to counteract this. Too much and you are just rolling around on the inner portion of the tire (contact patch more pie shaped with wider part on the inside), wearing it out slightly faster.

Toe - the angle formed by the wheel and the straight ahead direction of travel. Slightly inward helps with stability at speed, zero toe or even slightly outward gives more bite at turn-in. Again, too much toe leads to scrubbing of the tire as the car moves down the road and causes wear. Probably the #1 culprit for wear, especially when combined with incorrect camber.

Caster - multiple angles formed by the lower control arm pivot axis in relation to horizontal and vertical. Relates to how the wheel pivots up and down behind the axis formed by the front of the lower control arm. Because the center of the wheel is behind this axis, it lends some stability (think of shopping cart wheels). So it gives a stable highway feel. Also, higher caster contributes some extra camber when the wheel is turned, which is when you need it.

So, on our cars, the caster is fixed by the geometry of the front lower control arms. The rear mount is bolted to the sub frame, the front bushing is captured in the sub frame, and the outside is the ball joint connection to the spindle hub. So it isn't really adjustable unless you get aftermarket rear mounts that change the pivot point.

Camber is also fixed, because there are no OEM adjustments at the top of the strut where it mounts to the body, or the ball joint. But because there is some play in the holes of the sub frame where it bolts to the body, it is possible to shift the sub frame side-to-side to even out the camber. Various manufacturers make a set of collars to shrink and center the holes in the sub frame so that it bolts exactly centered and doesn't shift. USP Motorsport has two choices. Then there is the labor of raising the car and installing them with new bolts in key places.

I chose to do it, because racecar. The collars gave me even camber.

 

Thread update: Alignment Completed

First of all, thanks to louiekaps and jrutter for the tips and information.

I just got my car back this weekend from Tru-Line in Bellevue who in fact had to readjust the subframe to get my alignment reasonably configured.

Strangely enough, their assessment on the "before" situation was wildly out of whack with what Firestone said they dialed my alignment into.

Firestone said they dialed everything into "recommended range" except:

FL Camber: -1.1° (specified range, -1° through 0°)
FR Camber: -1.4° (specified range, -1° through 0°)
FR Caster: 6.3° (specified range, 7.1° through 8.1°)
Cross Caster: 1.0° (specified range -0.5° - 0.5°)

Tru-Line said that, actually, nearly all alignment numbers were out of whack except FL Camber, Front total Toe, and RL Camber.

Now, all that's out of whack, what they were unable to totally dial in, is:

FL Camber: -1.13
FR Camber: -1.28

These are marginally out of whack, and TruLine said they want to review the tire wear patterns in about 4,000 miles.

They said that the front subframe was shifted, and some fasteners that secure the subframe were damaged. They say it's not creating any issue nor is it a safety issue.

So I guess it's a game of wait and see.

 

Just my $0.02, but if you really want to be able to dial in the camber and have it 100% even, with a good contact patch, you need to get the tyrolsport subframe collar kit (or equivalent such as 034 or USP) and one of two things: camber plates or adjustable ball joints.

I went with the ball joints for three reasons:
1. They cost less
2. No need to remove the strut or cut the strut towers for adjustment (or install, for that matter)
3. No change in NVH

However, the route you're going is the correct way if you want to keep the car factory... but you may be in for a lot of visits to an alignment shop as the subframe tends to shift more as the car gets older. The reason is that the bolts that hold it in are torque to yield, meaning they should be replaced every time you touch them, which I doubt the alignment shop is doing.

 

I'm going to go ahead and throw in another recommendation for a subframe collar kit. I have the Tyrolsport kit (they were the only ones offering it when I did mine) and it solved 2 problems: 1. The subframe will inevitably begin to slightly shift as those stretch bolts continue to stretch, causing a pop/clunk noise when maneuvering at slow speeds like when parking, and 2. The aforementioned centering of the subframe from an alignment perspective.

I need to find my latest alignment sheet and see what my adjusted values are, but the alignment shop I go to is a track prep and suspension specialist and they were able to get basically every value dead nuts on what I wanted. My experience with Firestone is limited to one trip with my wife's Jetta, but I won't be going back to them. It seems like most alignment shops these days are pretty lazy and only do the bare minimum to get your car off the rack, and having any value out of spec is not really acceptable to me.