Need 15 -16-17 or 18's

to match (or stay close to) the factory tire height on my 17/18 combo I have found 205 or 215/50/17 for the front, and a 235/45/18 on the rear...

there is a great tire calc tool i found... it shows the difference in 2 sizes, and includes speedo chagnes. you can tinker for a while and figure out how to match overall height, sidewall height front rear, or whatever.

http://www.miata.net/garage/tirecalcold.html

enjoy

JOE