Tires: Tire Noise or Wheel Bearing Problem?, arizonian tires, cv joints

Question
I have a 1999 Dodge Caravan Sport (short wheelbase).  About 20K miles ago I put on 4 Arizonian tires from Discount Tire.  Tires performed well.  However, I now have a very loud annoying noise that sounds like tire noise (a humming/buzzing sound, not a squeal or squeak).  The sound resonates in the vehicle.  There is no apparant tire noise that can be heard outside the vehicle.  The tires have even wear.  I have just  had the wheels balanced and rotated and kept the tire pressure per the placard on the vehicle.  The noise can still be heard and has not improved after the balance and rotation.  The sound is the same while driving over asphalt or cement.  The sound pitch changes depending how fast I'm traveling.  The higher pitch is related to faster speed and lower pitch at lower speeds.

What could be the problem?  I'm not so sure a tread problem since the tires were quiet up to now.  Do I need to replace wheel bearings or alignment?  HELP!

Thanks.

DAN M.

Answer
Dan,

I love puzzles!

And the key to this puzzle was that the noise did not change between driving on concrete and asphalt.  If the problem was tires, it should have.

So that means the problem is somewhere else in the vehicle.  The likely sources are bearings and CV joints.