Tires: Uneven Tire Wear

Question
Why am I having more tire wear on the inside than on the middle to outside of my tires.  I noticed this condition on three sets of tires.  I always have a four wheel alignment done after tire purchase but the condition continues.  I need to mention that I rotate regularly (3k-5k)and I am getting the suggested mileage out of each set.  The last set were warranted for 50K and I got 50,338 miles but when the tires were removed they were smooth on the inside (safety issue)while still having 2/32 - 3/32 on the outside, front to back.

Your thoughts.

Thanks

Answer
First you have an alignment problem.  That is causing the wear issue.  Assuming that the alignments were done to the spec - than the problem is with the specs.  I have 2 thoughts:

1)  In my opinion the tolerances allowed for the alignment is too wide by half.  They need to be within the inner half of the spec to assure good tire wear.

2)  Any camber greater than 1° can cause a problem like you describe.  I notice that the alignment specs for a 2000 Toyota Camry have both the front and rear camber specs such that the allowable camber can be over 1°.

So you need to specify that you want as much camber taken out of both the front and the rear, such that the finished value is less than a degree.

The alignment shop may tell you that the car can't be adjusted  - and that is false.  Even though the factory didn't include adjustment slots, eccentric bolts, etc., there are things that can be done to get the alignment where it is supposed to be.  

I looked this up and there are eccentric bolts that can adjust the camber - and the alignment shop should use those.  

So go get an alignment and specify you want to see the before and after values. (usually there is a computer print out). - AND - you want the camber, both front and rear, to be less than 1° when the alignment is complete and if they need to get those eccentric bolts to get the values less than a degree, then you are willing to pay to have them installed.