My S60R has about 6200 miles. Just got the wheels changed back for summer to the P Rossis. When I drive with the rear windows open there is a low frequency sound. So low you feel it in your ears before you actually hear it. At about 30 MPH you start to hear it. By 40 MPH it becomes uncomfortable. A while back I read about a TNN for a problem with the exhaust hitting. Could that be my problem? If yes what is the TNN?<p>By the way, what is the TNN for the jumping rear. I am experiencing that also.<p>Thanks.