A humming or roaring from the wheels can be a failing bearing or just noisy tires - and they are easy to confuse. A few tests tell them apart. Here is how to distinguish wheel bearing noise from tire noise.
Does it change when you turn?
The best test: a bad bearing usually gets louder or quieter when you turn, as cornering shifts load across it - louder turning one way, quieter the other; see signs of a bad hub bearing. Tire noise generally does not change much with gentle steering.
Does it change with road surface?
Tire noise changes with the pavement - loud on coarse asphalt, quieter on smooth concrete. Bearing noise stays tied to speed regardless of surface; see bearing vs brake noise. If the sound follows the road, suspect tires.
Speed and wear clues
Both rise with speed, but bearing noise often has a rhythmic growl and may come with vibration or play in the wheel. Cupped or unevenly worn tires make a similar drone - inspect the tires for wear patterns.
Confirm and fix
Jack up the wheel and check for play and roughness by spinning and rocking it; see driving on a bad bearing. Replace a bad hub bearing and torque it to spec; see hub torque. Keep the brakes fresh with quality pads and hardware.