Strange Sound - 2005 T6 - What is it?

[shailey]

Folks,

I've searched the Forum for information related to the "problem" I'm about to describe, but didn't find anything....

I just bought a 2005 S80 T6 with 83K on the clock. I'm beginning to hear a periodic noise, kind of like "Whuh.....Whuh....Whuh" at a frequency of two or three cycles per second. I hear this between about 40 mph and 50 mph. I don't notice it when driving either slower or faster. The noise sounds a lot like a dragging brake caliper or wheel bearing, but I should hear this at ten mph to twenty mph rather than 45 mph. At 45 mph, the tires are turning at about 600 RPM, or ten cycles per second. I'm guessing, therefore, that this isn't tire-related. The tires are new Pirelli P6 with about 300 miles on them. I did not drive the car prior to the tire change, so I can't comment on whether this noise was present before the new tires were installed. I can feel a vibration associated with the noise through the gas pedal and, to a lesser degree, the floorboard.

Anyone have any thoughts as to the potential cause of this noise? I'm taking it back to the dealer for evaluation, but would like to hear from anyone with a similar experience.

Steve

[shailey]

Three of the 18" wheels were out of round. They were straightened and now the sound and vibration are gone. FYI.