The section on your main page that discusses how you make a small bike ride big erroneously states that "Gear inches" is the distance a bike will move (in inches) for one revolution of the crank arms (pedals). It's actually correct to say "Gear inches times 3.14" is the distance a bike will move (in inches) for one revolution of the crank arms (pedals).
In the days before bikes had sprockets and chains, one would purchase a penny-farthing based on the diameter of the drive wheel. When safety bicycles came in, bike shops had to come up with a way to sell them based on the metric that customers were already familiar with, hence "gear inches". See https://en.wikipedia.org/wiki/Gear_inches