Check this site:
http://www.miata.net/garage/tirecalc.html
There is over 1" diameter difference between the 2 tire sizes you list!  Enter your stock (205/65 15"?) tire size in the calculator, and you will see that the 235/40 18" wheel size comes closest at only 0.1" difference.
__________________
John
2003 Firemist Red/grey leather SL 500
2015 Palladium Silver/black mbtex GLK 350
1987 Smoke Silver/burgundy mbtex 300E Sportline (SOLD)
Click to see 87 300E
Last edited by JCE; 11-01-2001 at 11:39 PM.
|