Hi! I currently have the stock 195/55/R16 run flat tires on a 2008 S model. Is it OK to go a little wider (205?) and a little lower (50?) on the same size (stock) rim? I had a bad experience with a Lexus ES300 when I tried to put 215's on it when 205 was stock. Even though the "book" said it was OK to do so, they rubbed on the fender. Is there a "tire bible" that is accurate?

 

There's a whole forum where this sort of thing is endlessly discussed.

205/50-16 works fine, I've used those for several years. Some people run 205/55-16, I'm not quite convinced about those. Some people run even wider than that.