Tyre and Wheel Calculator

[DMWG40]

Hi
Is there any good tyre and wheel calaculator out there, I got one off another forum setup for the g40,a excel sheet. you can change the profile, but you cant change the speed and its set for 120mph.its locked i need to know what speeds I would be doing at normal speeds.

[hayesey]

loads of them if you google search "tyre size calculator".  A quick look at this one:

http://www.alloywheels.com/tyrecalc.asp

and it gives the percentage difference so you can work out the speed difference at any speed reading.  It also gives the answer for 70mph.

[DMWG40]

cheers for that, just wanted to figure out how fast I was going yesterday.