My Focus has the optional 16" rim package, which get wrapped in 205/50 R16 tires. The stock 15" option comes with 195/60 R15 tires. Now, although the 205/50 16's are the closest match to the 195/60 15's, they are still slightly smaller in diameter. I was considering using 205/55 16's for several reasons. 1) MUCH more popular tire size (GM, Toyota, Honda, etc), giving me more/better tire options. 2) 0.8" bigger diameter, meaning 0.4" thicker sidewall, meaning smoother, quieter ride. My Focus doesn't exactly have soft suspension or much soundproofing, so I'm all for a smoother ride. Now, the 205/55 16's are slightly bigger that the 195/60 15's, than the 205/50 16's are smaller. Does that make sense? My speedometer already reads slightly fast (based on all of the speed sensors around town) so the 205/55 16's could help make my speedo more accurate, too. No fitment issues with the bigger tire either. I've only seen one other Focus with the 205/55's fitted. Opinions? I just wanna make sure that the bigger tires won't throw off my odometer or speedo by some crazy amount, based on something I've failed to consider.