I would jack up that wheel. Then you can spin it and see if the sound is still there. If not then it could be the tire as you say. If so you could also observe the tread problem by spinning the tire and watching the tread. If the noise is still there then you can hopefully see what the issue is.

__________________
1998 C230 330,000 miles (currently dead of second failed EIS, yours will fail too, turning you into the dealer's personal human cash machine)
1988 F150 144,000 miles (leaks all the colors of the rainbow)
Previous stars: 1981 Brava 210,000 miles, 1978 128 150,000 miles, 1977 B200 Van 175,000 miles, 1972 Vega (great, if rusty, car), 1972 Celica, 1986.5 Supra