2007 Chevrolet HHR • 193,000 miles

I recently had uneven wear on my tires and started hearing a noise that I thought was caused by the bad tires, sort of a humming that increased as the speed increased. I had the tires replaced and the alignment checked but I still get the humming noise. If it was a bearing, wouldn't it be more of a screetch or metal to metal sound? I am going to take it to my mechanic but I am trying to figure out what it could be. Any help would be appreciated.
November 9, 2012.

No a bearing can do that. I had a car that had a vibration, low hum that would go through the car from 46mph up and it was always there. Sometimes louder than others. FINALLY it was the front wheel bearings even though I had changed them several times. The ones that were being put on were not the right ones for the car. They road just very slightly high on the race. Replace and no noise.

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Nov 9, 2012.