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