Tires: 2 wheel vs 4 wheel alignment, wheel drive vehicles, wheel alignment

Question
I'm going to be replacing the OE tires on my 2006 Chevy Monte Carlo LT (3.9L) soon, and I was wondering if its necessary to get an alignment at that time.  The car doesn't seem to be pulling one way or the other now.  Years ago, it seemed that just getting a 2 wheel alignment was fine, but now it seems that the shops are pushing the "4 wheel alignment".  Is it really necessary to get a 4 wheel alignment vs a 2 wheel alignment?  What is there to align on the rear wheels anyway, since they don't turn?  Seems like just something the auto shops came up with to get more money!

Answer
Mark,

 A good rule of thumb is to have your vehicles alignment checked and adjusted if necessary anytime you have tires installed.

 Even if your vehicle is not pulling the alignment can be off enough to cause irregular wear in your tires.  Once a wear pattern is started it is very difficult to correct.

 On ALL front wheel drive vehicles the manufacturers recommend a four wheel alignment.  Let me se if I can explain this to you about aligning all four wheels.  When a four wheel alignment is performed the rear wheels are adjusted to spec if required.  Once the rear wheels are set, the front wheels are aligned according to spec in relationship to the rear axle.  This allows all four wheels positions to track properly in relationship to each other.

 Hope this helps you to understand the purpose of a 4 wheel alignment.

*** Mark, I read your rating and I am not sure what I didn't address.  Please feel free to send me another question whereas I address the Root of your question ?