Epicyclic Motion

Everything depends upon the sizes of the gears. The rates at which the gears, and rings, and planet assemblies rotate is governed by their number of teeth relative to each other. In the ubiquitous Sturmey Archer 3-speed hub, the numbers are;

 sun gear = 20 teeth

 planet gears = 20 teeth

 ring gear = 60 teeth

 One notes that when Martin Luther first saw the newly invented printing press, he said "There's a Devil in it!", and he was right.

Fully Awesome

The Sturmey-Archer hub is an awesome machine which routinely runs for decades on a few squirts of oil. In "the Era of Giants", that is, the past, SA hubs were available as close-ratio 3sp, wide-ratio 3sp, close-ratio 3sp-fixed, and many others. The great Eddy Merckx rode nothing but! Olympic Champions swear near them. Anyway they are still a good option, say for a commuting bike; though in Asia they use them for everything. In future posts I will attempt to refute the Categorical Imperative and show how SA hubs work, and a little about how to fix them as well as other cool bike stuff. Onward and Inward!