One of our cars is a 99 Stratus with 86K miles.  A few weeks ago, my car was
in the shop for the timing belt replacement and I had my wife drive me over
to the shop in this car.  I noticed a pretty loud whirring noise coming from
the rear of the car that increased/decreased with speed.  I almost sounds
like large lugged truck tires driving down the road but not as loud. I was
thinking the wheel bearing might be going out so I jack up the car yesterday
and there is no movement in either of the wheels with the parking brake off.
I would think that if a bearing was going bad, there should at least be some
minimal movement there.

So then I looked at the tires and on both rear tires, the inner tread groove
had a noticably raised slightly jagged tread pattern compared to the the
other lines of tread in the tire....If a tire was bad, I would think it
would happen on only one tire and not both on the rear, but this was the
same on both tires on the rear.  I wouldn't think this is by design.  So I
went ahead and rotated the tires..rears on the front on the same side to see
if the sound moved.

I can still hear it and it does sound like it has moved from the rear to the
front and the wife confirms this.  So am I still looking at a tire issue or
still a possibility of bearing somewhere? Turning sharply left and right
doesn't seem to make a difference in the noise (noise decreases but probably
just due to slower speed, but doesn't fully go away.)

I guess I'm just puzzled about both rears having the same unususal (at least
to me) wear.

Do you think that the raised inner tread will wear down in time and that is
where the sound is coming from, or do I have a deeper issue?

Looking for any advice as I'm just not finding much on steering/suspension
issues on the 99 Stratus...If there is, could you point me to them??

Thanks,
Mike