the inside of my rears, especially the left, wears at a ridiculous rate (or maybe not, considering i am constantly spinning the car to the left, hmm...), but seriously all jokes aside, the added width of most 20's compounds the already negative camber these cars come with, and if your tires have a low tread wear rating (as most cheaper tires do) this will wreak havoc on them. I am a tech at a chevy dealership in the sacramento area, and as such have the privilege of unrestricted access to an alignment machine. I try to check my alignment at least every couple months, es pecially when I run my 20's ( april-october) and a trend I see often is the toe set getting out of wack, this causes the tire to move in or out at the front and will make it "drag" across the ground, this wears them out even more than negative camber, so keep an eye on it
