tweetdriver63 wrote: and the 55 vs 45 would make the actual speed 7.2% higher than indicated. Therefore, the speedo would end up indicating about 2% or so higher than actual....a lot more accurate. However, I would think the handling would have to be affected by a tire with a .85 inch larger radius. Probably not noticably for normal street driving though. I wouldn't think that difference in diameter would make them rub in the wheel arches, though, but I could be wrong there.
Don't forget, Chris - Jeff is talking about 15" UK wheels, so the increase is from 50 profile to 55, but the overall effect should be as described (less distortion in the speedo reults, and a slightly smoother ride, but at the expense of a bit of roll in corners.....
....as to hitting the arches, well, if it didn't, then it didn't - so what else can you say!

