My stock size is 195/60/15 I was runnign 195/55/15 for a while with no problems.

Here is a Tire Size Calculator that may help some.

IMO running 55's was fine for me. it gave me a little more wheel well space but I havent droped my car yet eaither.

I am back to 60's cuz they were given to me and I needed tires.

I am planning on going back to 55's if I stay with my 15 in wheels or I'll go to 50's if I go to 16's.