Nissan Repair: shimmy & vibration, cv joints, b f goodrich

Question
I recently had the tires on my 2000 Maxima rotated and balanced.  After that I had quite a bit more vibration coming from the wheels.  I took the car back to Discount Tire, and had them balance the tires again.  The problem was still quite bad.

Knowing that the CV joints were knocking during turns, I presumed that maybe the CV joints were causing some of the vibration.  So, I had both CV joints replaced.  It was smoother, but still I had noticeable vibration at just about all speeds.  The noise is most noticeable at 20mph, but still very evident at highway speeds.

The car has been aligned within the last year and no major hits to the tires since then. The tires (B.F. Goodrich G-Force Sport) have an aggressive tread design that helps the car handle quite well.  There is almost no vibration in the steering wheel, leading me to think that the front tires are well balanced.

The shop that has done the CV-joint repair and the alignment  seem to think it is the tires.  For that to be true, it seems like Discount tire would have caught the problem during the 2 occurrences of balancing the tires.

What would most likely be the problem at this point?


Answer
T,

It is probably the tires not being balanced correctly.  I would take the car back and have them do a balance with weights on both the outside and inside rims and make sure it balances out to zero on all tires both inside and outside.  If this is correct then the tires are probably out of round or the belts are seperating.