Why are the gears and chain always on the right‑hand side of bicycles?

5 April 2023

Enrique Diaz/7cero/Getty Images

Why are the gears and chain always on the right-hand side of bicycles?

Richard EllamBristol, UK

The short answer is because most people are right-handed.

When the first chain-driven bicycles were designed, around the year 1890, the easiest way to attach the sprocket for the chain on the rear wheel hub was to screw it on. The mating screw threads were made using screw-cutting lathes, and these were (and still are) optimised for right-handed users. This meant it was much easier to cut a right-hand thread than a left-hand thread.

A clockwise movement tightens a right-hand thread and it …

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