mx5cartalk.com

I've been looking at what tyre I'll need to fit to my NC to get close to the same rpm/speed as std for cruising if I install a 4.1 diff for trackwork.
Found this easy to use program which although in MPH is good enough.
http://pw1.netcom.com/~sgalaba/mph.htm

Looks like a 235/45/17 is close and would give a limo ride

Looks good - tks!

If you've not seen it, useful from a slightly different perspective, especially for multiple comparisons: http://www.1010tires.com/tiresizecalculator.asp

Heres the one I use http://locost7.info/gearcalc.php

i like it because you can see your RPM in every gear