Wheel alignment specs?

Many vehicles are so accurately manufactured, there isn't a provision to change the alignment. In this case should abnormal tire wear or tracking issues occur, alignment changes can be made by installing retrofit offset/adjustable bushings or shims. Apparently custom shims could be used to adjust rear alignment, but that's a lot of physical labor (read that as expensive). There would be a lot of dismantling, reassembly, and recheck of alignment, and repeat the procedure until the alignment was okay. The other method to correct rear misalignment is replacement of suspension parts (again pricey).

Camber is the inward/outward tilt of the tires. Inward is negative camber. Outward is positive camber. Your left rear has too much negative camber, so it will wear (ride) more on the inside. Too much toe means the tire(s) get scrubbed off a bit faster. I think its toe that affects your car pulling to one side; however, it's damn hard to find a perfectly level road on which to drive for a distance to check pulling. Most roads are crowned to facilitate water runoff.

You never mentioned the year model for your Tribeca. I found some specs for the 2006 at:

The show degrees and seconds, not decimal degrees as in the report the shop gave you. So, you would have to multiply their decimal degrees by

60 to see how many seconds is the equivalent, like 0.05 is 0 D 3' 0" (degrees, minutes, seconds). For your fronts, the difference in cambers for left and right is -0.2 - (-0.2) = 0, so good. For the difference in cambers of your rears, -0.6 - (-1.3) = 0.7, and the chart says the difference should be 0.52 (0 D 31 minutes which borders the max according to the chart); however, cambers are not symmetrical.

From what I've watched when they checked alignment, the equipment is clamped onto the wheels. They don't remove your tires+wheels and install some reference wheels. They don't spin the wheels to get an average alignment measurement for the complete rotation of all wheels. So, I have to wonder if the wheels aren't perfectly balanced (I mean in their geometry, not in rotational stability) then maybe the measurements would change if the wheels were rotated a bit.

The rears are officially "not adjustable" which really means it's expensive to fix. If you don't want your tires wearing unevenly (excessive camber) or scrubbing off prematurely (excessive toe) then you'll pay for getting new rear suspension parts (or maybe the problem is with your wheels), and that cost could outweigh the cost of replacing your tires a few months earlier (i.e., your tire cost is accelerated due to decreased lifespan, but obviously that's also affected by your driving style and how often for emergency braking).

The cambers are just a wee bit out of spec for my fronts on my '02 Legacy wagon. The rears are within specs. I couldn't get the fronts aligned because to the tie rods are siezed. There's the cost to replace the tie rods, plus the cost for alignment. That car only gets 1400 miles per year for mileage. Yeah, v-e-r-y little wear. The tires may get some uneven wear, but they don't get much wear at all. So, for me, I can put off getting the front alignment. I'll get a tread depth guage to monitor the inside and outside tread depths to check how the out-of-spec camber might unevenly wearing the tire.