also check for bruised (bulged) sidewalls... I know that the Xfire I got a few weeks ago needs one tire for the left, and the right has a slight dent on the inside... a "Good" tire person will tell you about the damage on tires when you have them spin balanced... also, either of these can cause vibration issues... funny thing... the guy that sold the car tried to tell me that A. he did not feel the vibration, B. it was the road... all cars do that, and C. that (get this) "if the vibration is over 50 MPH, spin balancing won't fix this... because the machine won't go that fast..." I was like WHA??? I have STATICALLY balanced wheels for DC-10's and 747's... and they don't vibrate at almost 200MPH! :P

anyway, belts, bruises and uneven wear are signs that the tire is damaged... and yeah, can cause vibration... as can bent rims etc... alignment will generally not, if it is the cause it will frequently show as wear... look at the charts at a tire place...

Seannon