Reply to "Tires/wheels advice needed"

Shah,

Your rear tires sound like they are too short, but I doubt that hurts acceleration. I can't answer whether the diameter difference would be perceptible when driving, but I can say with certainty that on my Pantera I can tell the difference in acceleration between my light 15" magnesium wheels and my much heavier (and thus slower) aluminum 17" wheels. Perhaps the difference I feel is exacerbated by the rotating mass being further from the hub on the 17" wheels, but there is a noticeable difference. I experience this on one of my other cars as well. I haven't measured the difference with a radar gun, but I doubt it's more than 10–15% on the 0—60.

That said, acceleration and braking will probably be much more significantly impacted by your tire choice than the rolling diameter. My new Pirelli P-Zeros are a LOT stickier than my 8-year old Dunlops. If you go from old 15" rubber to fresh 17" rubber, you will probably be happier. This will be especially true if, as you say, your wheels do weigh the same.

Mark