Technical details

Gearbox type

It is a planetary gearbox.


It will add about 200-300 grams to the weight of your bike if you remove a three-chainring crankset of good quality (with aluminum cranks) and put the Efneo gearbox on your bike.

Gear ratio

Overall gear ratio is 179%.

2nd to 1st is -30%, 2nd to 3rd is+25%.

Efneo’s gearbox is equivalent to a front crankset with 28T/40T/50T chainring.

Frame compatibility

You can put Efneo gearbox on any frame designed for a tapered square axle bottom bracket 68mm (ISO/English), used in almost all of the city, urban, single-speed, hybrid, trekking bikes, as well as trikes & recumbents.

Please, see here how to check if Efneo gearbox fits your bike.

Gear shifting

You can change gears when you are not pedaling.

You can change gears under load when upshifting a gear. You have to loosen your leg a bit when downshifting a gear (like in most bicycle gearboxes on the market).

Shifter and cable

Trigger and twist grip shifters available, you can see them in this movie.

Shifters fit 22,2mm diameter handlebars.

A lot of different cable positions are possible – please, see examples here.


40,5 mm


177 mm

Crank length

170 mm

Gearbox disc diameter

130.6mm (graphic)

Rear transmission compatibility

Can be paired with a rear derailleur, rear gearbox or single-speed hub. For a rear gearbox check the maximum front chainring suggested by the gearbox manufacturer (they often require minimum 34T, and the Efneo gearbox has 28T); this condition does not apply to bikes with much smaller wheels, then standard 26″-28″, for example folding bikes.

Chain / belt compatibility

We will offer a chainring for 1/8 and 3/32 inch chains.

The chainring is made from a very high quality Chromoly Steel 32HRC.

Soon we’ll offer a sprocket for a carbon belt (Gates Carbon Drive®, CDX 46T size).

Installing gearbox on your bike

Installation is presented shortly on this video.

The gearbox package includes:

– a rigth crank, with a gearbox inside,
– a left crank,
– a square tapered axle bottom bracket,
– a shifter, with a cable,
– a complete installation manual.

Maximum torque

We guarantee the Efneo gearbox works perfectly in all conditions except for extreme off-road applications like downhill or professional MTB.

Coating and colors

Crank will be painted. Black and silver versions will be available.

No embossed / engraved logo will be put on the crank, so you can also repaint the gearbox, if you wish.