Alan-
I didn't know a thing about alignments until after my steering retrofit a few
months ago. You can tell how frustrated it made me.

. I was also surprised
at how poor the information is on alignemnts. IT took me lots of reading from
tons of different sources to figure out the "right" way. In the end, it turned out
to be quite simple. ITs just that most dealers only do a few (or none) of the
necessary steps- and you really have to pay attention to everything to get
good results.
1. The rear alignment is an interesting subject. If the rear toe is uneven, it
creates a "thrust angle", meaning that the wheels are both point in a direction
to either the left of right of the geometric centerline of the car. If you think of
a hook and ladder fire truck w/ rear wheel steering, you'll get the idea of what
this does-- it causes the car to turn in the opposite direction of the thrust
angle. If the rear wheels are facing opposite directions like this: \ /, it creates
a dangerous toe-out condition which can causes sudden severe oversteer. I
really doubt that you have this condition. Its hard to know just from driving
the car if the rear isn't set right- although a rear misalignment tends to cause
more dramatic pulling than the front. By the way, a "thrust angle" can be
compensated in how the front toe is set. You may have seen the term "thrust
angle alignment". THis is when sensors are attached to all 4 wheels, but only
the front toe is adjusted-- and its adjusted such that they front wheels are
pointing in the same direction as the rears. This will allow the steering wheel to
be straight,and for the car to travel straight. But, if you think about it- the car
will also be travelling slightly diagonally relative to its body. If sensors are
only attached to the front wheels when doing an alignment, and the rears
aren't taken into account, the car will end up pulling in one direction. Of course
the right thing is to have the rear toe set evenly side to side and to toe-in
slightly and for the front to do the same. The amount of total toe in the front
and rear doesn't have to be the same though. My car's rear toe was out of
spec, and apparently the first dealer hadn't done a proper alignment. I finally
had both the front and rear set evenly-- but my steering wheel has been
crooked in several different ways-- so that's all i'm really working on now.
2. Interesting point that you bring up about the tires "setting in". Its true that if your alignment is off, your tires will wear poorly. Depending on the tire and the alignment condition, there's all sorts of different wear problems that can result. Unfortunately, from what I've read, it appears that after a certain point (about 1000 miles), is nearly impossible to wear the tire back into proper shape following a proper alignment. But, the good news is that I doubt your current and previous alignments were off enough to cause any bad wear. Again, I really think the problems you're experiencing mostly have to do w/ the alignment itself and not the the tires condition. You can check the tires-- Is there more wear on the inner or outer side? Is there a "saw-tooth" pattern across the tread blocks? Is there wear on both sides but not in the middle?
Alan F said:
Rob, thanks for that incredible write-up . . . it's amazing how much you know about this particular subject.
My steering wheel feels perfectly straight and the car really feels like the front has been done 100% correctly. My real concern is the rear of the car.
Something feels a little strange like it's off.
I have 2 questions for you
1) By driving your car, how can you tell if your rear alignment is off ?
2) Once you get an alignment, do your tires have to break in to the new pattern they are set in ? Kind of like when you get new tires and they feel weird at first but then after 500-1000 miles they are broken in to your car .