Tires: unusual tire wear on rear, chev malibu, firestone tires

Question
I have a 2003 Chev Malibu. The right rear tire is wearing with an unusual pattern and is making a lot of road noise. The wear is indentations about an inch wide, about an inch apart on the outside of the tread, all the way around the tire. It is front wheel drive. What could cause this? It has the original Firestone tires.

Answer
Hello, Morris

I had a set of Michelins do the same thing. I did not rotate the tires until about 20K and when I did the front ones were wore a little on the edges like you said. After putting them on the back there was so much road noise I had to buy new ones. I think it was because i waited to long before rotating them but am not sure.