Howdy,

Yes I know what you mean. I was actually alarmed the first time it happened. I thought a tire had come apart or something. Something about the size/shape of the windows. Oddly enough, my wife's Jeep Liberty is really bad with the windows down at 35-40 mph. I think it has a lot to do with how the airflows around the "A"-pillars and mirrors. Remember "vent-wings"; I bet if we had 'em the problem would be solved. I've owned a number of sixties vintage two door hard-top muscle cars with the little triangular vent windows and NONE of them ever displayed the throbbing/thrumming air flow. I also have a Cherokee with "vestigial" fixed vent windows and it does not exhibit the problem either.

I know they are "old fashioned" but hey, those little "vent-wings" really did work...

Slim