MX-3.com

Just found this little tool since i had to put my g/f's spare steelies on my mx-3 while i work on it.... http://www.net-comber.com/tirecalc.html" onclick="window.open(this.href);return false;

I like doing that on paper instead

I like to use http://www.miata.net/garage/tirecalc.html" onclick="window.open(this.href);return false;

My personal favorite
http://www.1010tires.com/TireSizeCalculator.asp" onclick="window.open(this.href);return false;

I like to use http://www.rims-n-tires.com/rt_specs.jsp" onclick="window.open(this.href);return false;