For about the past month, I've noticed that I'm getting a rolling vibration.....kind of a grinding feeling from the left front wheel. It is constant when going in a straight line but increases during right hand turns, getting worse the more I turn the wheel. The vibration / grinding can be felt in the steering wheel. However, during left turns, where there is less load on the left front wheel, it is almost un-noticable. About 6 months ago, I changed the front brakes, rotors and hubs and the car has driven beautifully up until the last month or so.

What could this be? I checked the brakes and the torque on the hub and everything is in check?

Any ideas?