tires can be odd, try rotating the tires and seeing if the problem changes.

the humming occurs if both are going IME.
if it's only one for some reason (you nudge your driveway kerb on one side everyday for years...) it can wobble. i had this exact problem in my RX3 and i was told it was tyres, so i put new ones on and the problem was better, but still there. i changed the wheel bearings and problem solved.