I've been having this odd high pitched humming noise that may have to do with a suspension component. I had the rack and pinion replaced a week ago in order to fix a clicking noise while turning. It's hard to say whether this noise was there before or after the rack and pinion, I've definitely been extra cautious since then.
The noise comes up above 15mph and stays at all speeds. It does not change when turning from left to right or right to left. The wheel has no play at all and no resistance when turning the wheel while jacked up.
I took it to a repair place and they said everything was fine with my car. After getting in my car and going on a test drive with me the mechanic said it could be a bearing getting ready to go bad but he wasn't sure.
All 4 tires have wear on the specifically on the outside, it's not down to the tread line yet but one of the tires is close.
I would record the sound but it is not loud enough to be heard on a video.
2011 Ford focus 74,500