Originally Posted by MarkE90M3
why use miata.net's calculator when we have our own in the wheel and tire forum (at the top of the forum).
as for the diameter, the overall diameter is the same no matter which e90 you get.. the larger wheels on a 330 is balanced by smaller tires to achieve the same overall diameter, which is the key.
Thanks guys, I should have looked at the wheel and tire forum. Sorry to be so stupid.