I've got a 98 S70 with 175K on it.
I have a right side front end noise that sounds like tire noise. The noise appears as the car is picking up speed. The best way to describe it is, it sounds like the noise you would hear from the tires of a large truck as it passes you.
I've rotated my tires, noise is still there. I've put different tires on, noise is still there. The front end has been aligned, and the tire pressure is correct.
Thinking it may be the wheel bearings, I asked my mechanic to check it out, and he said all looks fine. I also did the test where you jack up the car, grab the wheel at 12 & 6 o'clock and shake to check for worn bearings, no noticable movement.
I've tried listening as I turn the car left or right to see if (it were a bad bearing) when the wheel is loaded or unloaded, the noise remains or goes away. I really can't hear a difference when I turn. Also, there is no clunking or other types of noises associated with this.
Any ideas on what else to look at?
Thanks
Mad Finn

I had the same problem (twice on the same wheel). It ended up being the wheel bearing, which of course is not just a "replace the bearing" deal with Volvo. It is a bearing hub that has to be replaced.

If you leave it long enough it will eventually begin to make the noises associated with a bad bearing, but the noise you describe is the beginning.

I agree that it is most likely the wheel bearing. Mine sounded the same way and I initially suspected the tires too. About $150 for the assembly and Bay 13 has the instructions you will need. Takes about 2 hours to do.