Hum / Noise with Sunroof Open?

[consultant1027]

Anyone on their G Sedan, notice a low hum when driving between 30 and 45 MPH with sunroof all the way open. It goes away if I close the sunroof so it is only 2/3 open. I'm wondering if maybe the particular tires are the car are resonating is the cause or is this something a lot of people hear. Anyone tried putting one of those little lips on the front edge of the sunroof opening to reduce noise?

[biggie]

Probably the air going over a cavity. Just like if you roll down just the back windows. See if you open the sunroof and then crack a window or 2 and see if it goes away.

[consultant1027]

Ya, I know what you are talking about. Cracking a window slightly doesn't make much of a difference. A manufacturer isn't going to turn a car out that when the sunroof is open it sounds like an 18" subwoofer is humming in the trunk. It definitely isn't normal. The rear tires have a very aggressive (high performance) looking tread pattern. I think first thing is rotate to see if the other tires on the front when moved to the back solve the problem.