I bought a Focus last year and ever since I got it, I noticed a grinding noise when turning left at high speeds (50 mph and up). Now I got it to a garage and the guy thought it was my brake discs because they were warped (they shuddered when I would brake) so that was fixed but the problem is still there.
I thought it was a wheel bearing at first but then I also think it could be a CV joint? It's odd as it only happens at higher speeds. When I do a 3 point turn or turn the wheel when stationary it's silent so I know for sure it's not my power steering.
Jack the front end of your car up and pull on the wheel. If it moves, it is probably the wheel bearing. If not, it is probably the CV joint.