TIRE SIZE CALCULATOR
 

Found a great site that allows you to compare your stock size tires with up to four other sizes at once. Gives size difference, revs per mile difference and speedo difference.

http://www.1010tires.com/tiresizecalculator.asp

That's a good calculator. It's already shown on the Wheel Gallery and Fitment Guide as a usefull link along with some other very good calculators.

http://www.ft86club.com/forums/showthread.php?t=7535

I have always used the Miata one - http://www.miata.net/garage/tirecalc.html

I have been using both for quite a few years now. For the last four years+ I have preferred 1010.

here is another good offset calculator

http://www.rimsntires.com/specs.jsp

Yup, almost all of those are already linked in the Wheel Directory...

but I did add the rimsntires.com one... thanks miodculae!

This is the one I've always used. +1