A bicycle anatomy guide

2025-06-02

A bicycle anatomy guide

Bicycle anatomy can be both incredibly simple or frustratingly complicated. At a very basic level, a bicycle is two wheels with a frame, pedals and handlebars. Turn the pedals, the wheels go round and hey presto.

Sometimes though, there is a need to go much deeper into the detail. For example, if you need to explain to a mechanic what is wrong with the bike, or if you need to describe the bike to the authorities should it, or parts from it, ever be stolen.

If you’re not sure where the bottom bracket is, or what a derailleur is, then our handy bicycle anatomy guide for beginners is for you.

It’s a very good idea when you buy a new or second-hand bike to keep a record of exactly what parts (and the make and model of each part) are on the bike and any unique characteristics (such as a two-inch scratch on the down tube – do take photos).

Most online listings for new bikes have all the parts (including the all-important brand and type/model) conveniently listed. If you change/upgrade a part, do update your records and any online bike registration database records (such as with immobilise.com that the police have access to should a stolen bike be recovered).