Originally Posted by StiGuy
Ok let me rephrase.
I'm interested in all out performance while staying as close to stock as possible. That's why I wasn't considering other sizes. The new wheels are 18 x 8.
There are the following differences from stock tires size according to this tire size calculator (
http://www.1010tires.com/TireSizeCalculator.asp):
225/40/18
Diameter Difference: 0.44%
Speedometer Difference: 0.434% too slow
Actual speedometer reading instead of 60mph: 59.7
235/40/18
Diameter Difference: 1.7%
Speedometer Difference: 1.722% too slow
Actual speedometer reading instead of 60mph: 58.9
245/40/18
Diameter Difference: 2.88%
Speedometer Difference: 2.954% too slow
Actual speedometer reading instead of 60mph: 58.2
Hmmm, well if you concerned about your speedo being off, tires are the least of your worries. The STi speedo is known to read higher than the vehicle is actually traveling. My friend Rob brought a TomTom GPS on our recent roadtrip and we determined that with my cruise control set at 79mph, we were actually going 74. That is a much larger difference than the tires would make. Again, if you want maximum gription (yes, I know that's not a word), you should go wider. Just something to consider.