Gears are a pretty fundamental part of the modern bicycle.
In fact, as the handlebar-moustache-sporting, Victorian gents amongst you will know, the introduction of gear rings and chains spelt the end for the Hi-wheel (the Penny Farthing to you and I) and other direct drive bicycles.
By varying the size of the chainring at the front and the sprockets (or cogs) at the back, cyclists could generate greater speeder without having to spin the pedals at ever-increasing RPMs (or balance precariously above gigantic front wheels).
In this post, I’m going to give an introduction to bike gears.
Since this is a blog about road cycling, I’ll stick to talking about derailleur gears (i.e. the ones seen on road bikes). Conveniently, this means I can avoid having to admit that I really don’t understand how hub gears work (what? ah…).