Cadillac Repair: Hum, wheel bearing, road surfaces

Question
I have a 1994 Eldorado, whenever I accerated and reach 30 mph, my car starts to hum.  At times it hums so hard that I can feel it vibrating.  What could be causing this?

Answer
Hi Terry, On differant road surfaces tires can hum. What I am suspecting though is a hub and wheel bearing assembly that is going bad because it will hum in a speed range. When the hum is the loudest move the steeering wheel so the Eldo moves side to side in a lane farely quickly so you get the car to lean and the side with the bad bearing will get louder as more weight is put on it and run quieter as the weight is taken off. You need to do this in a place with no other vehicles around. Hope that helps. Bill