Efneo: 3-gear front gearbox for bicycles

Efneo is a planetary gearbox that promises quicker and easier shifting than a conventional front derailleur.

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There is a slight weight penalty of 400g, but in its favour efneo does away with the need for tiresome, tricky adjustments.

A conventional front derailleur has three chainrings of different sizes rotating at the same speed.

The efneo has one chainring, rotating with different speeds on three different gears. The design allows you to change down to first gear at a standstill and then pull away easily without any chain-dropping. Visit the efneo website.

How does a planetary gear work?

Epicyclic gearing or planetary gearing consists of one or more outer gears, or planet gears, revolving about a central, or sun gear. Best demonstrated by the simple wooden model below.

https://youtu.be/-ue_usZqHYs?t=1m51s