Wobbling feeling on driver`s side wheel while driving

My gf`s car,1998 Olds 88 started having an odd problem. When you`re rolling,it feels as if the driver`s side front wheel`s warped or something. The steering wheel shakes and the speed of the wobble increases with car speed. I checked what I could.........watched the wheel while she was driving and didn`t notice anything. I checked all the lugs and they`re tight. Nothing looks odd about the tire and there`s no uneven wear or anything. The suspension looks good.

What could be the cause of the wobble??????

Could be off balance, a bearing, a broken belt in the tire, etc. swap the front and rear tires and see if the wobble follows the tire(s) or stays in the front.