I know this is not directly a DIY thread but it seemed the most appropriate place for it since it's accurate info not hearsay or opinion.

This is an old 2001 version, there are newer versions but I've been unable to locate one - they are essentially the same, just a little different in format.

Young folk get out your calculator...old folk better go find the slide rule...enjoy!

Michelin tyre grip... http://www.dimnp.unipi.it/guiggiani-..._Tire_Grip.pdf