I think it's tire cupping, which is caused by alignment.

來源: 於 2012-01-23 01:15:09 [博客] [舊帖] [給我悄悄話] 本文已被閱讀：次

You need to change tire (source of vibration) and check alignment (source of cupping).

What kind of car is it? I had tire cupping problem with my last car, 97' Honda Civic, forced to change tire at 30,000 miles for 70,000 mile life tires.