rounder1122

I have a loud noise coming from the rear of my car. It sounds like a flat tire. I thought that it was the rim or tire but its not. I bought new tires and rotated the rims. It follows the speed of the car exactly. But it doesn't cause any vibration. It sounds like " whoap whoap whoap whoap" if you can imagine a sound from that word. like " whoa" with a P at the end. Any help is appreciated.