Other last week, I took a little 2 hour road trip of hwy driving last week. This sound is that appeared, few days ago. At high speeds I notice mild sound. I took both front tires off to inspect whats going on, Within the last year all four wheel bearings have been replaced with new parts. New brakes and rotors. I checked the front end parts, Ball joints / tie rods ends / All bolts on calipers, Ive looked at both front tires they are all season tires , Maybe 2 years old they have 85% rubber left. I noticed the right passenger tire has small cracks in the bottom portion of the trend, Also like a separation, The tire could heat up then cause this mild Sound. It only happens from 80 kph to 120 kph. Just wondering what you guys would think. My car is 01 cavalier 2.2L engine, 4 spd auto.

Thanks for you're help.

If you already checked the suspension parts, have you checked if your tires are balanced? I know it sounds stupid, but my sisters Jetta had a similar problem (a high pitched whining sound at high speeds). We took it to our mechanic and discovered that the front left tire was completely missing wheel weights, and the right rear was out of balance. After a re-balance and rotation, the sound went away.

I know it sounds odd, usually when tires are out of balance, you'll get vibration in the wheels, but you learn something new every day, I suppose. A little dry rot in the treads of your tires shouldnt be causing it, I had that on my '01, never had a problem.

Anyway, hope this helps.

Thanks for the helpful tip. I took my car in to the tire shop, cracks in the tire were normal wear. Tires needed to be rebalanced. Got them done nice and smooth now.

thanks again.