left front end humming noise

I've been getting a humming noise from the left front end of my 2001, 4WD. Starts at about 20mph and does stop. Any ideas, thanks for the help.

Greg

Very little to work with here...

I would first make sure that the noise is actualy coming from the front left. Opening your window will make everything sounds like the front left. Have someone outside listen while you drive.

If you just installed bigger than factory tires they will hum.

Just had the same problem with my 99 windstar, wheel bearing!