mechanical noise which follows vehicle speed in my 95

[nuck]

I have 100k miles on her. Recently I have been experiencing sounds which I thought where tranny related but which seem to follow the vehicle speed after initial silence for the first couple of minutes of driving. Almost like a flowing sound, or the continuous drone of the heater or a/c system. but this happens with the heater/ac off. It comes only while driving, and disappears at a dead stop. The tranny seems to shift okay(has been loose for 50kmiles but no different now) The car isn't runing long enough for it to be actual coolant flow. Any thoughts? thanks

[nuck]

I am starting to think it might be my tires. They have just over 50k miles on them and are not a high end brand. This would fit with the noise taking a while to appear as the rubber had to heat up. The bug hunt continues.