Fixie Calculator for Android
Divide chainring teeth/cog teeth with your calculator of choice... Ratio! Skid patches?... Reduce the previous fraction; its denominator = Patches! Congratulations, you now have this app's abilities. Feel empowered, bike geek! :D
Good nice..
by B####:
Its simple and easy but maybe too easy, there are no tire or rim sizes. It actually affects the ratio.