nFIXED London


Sale price Price £429.00 Regular price Unit price  per 

GTRO Gearbox

Are you like most people that really don’t like all the hassles and problems associated with a front derailleur? Now you have an alternative.

Efneo’s GTRO 3-speed front gearbox is perfect for trekking, hybrid, urban, single speed, city and folding bikes as well as for off road non-competition bikes and e-bikes.

Advantages for you

Easy to start from the first gear With Efneo you can reduce to the first gear in a standstill – like in a car – and start easily in 1st gear.

Immediate gear change Much quicker and easier than with a front derailleur. Change gear when pedalling and in a standstill.

No chain-skewing No chain-skewing and chain-dropping when paired with a rear derailleur.

Easy to install The easiest front gearbox to install ever. No frame modifications necessary.

Reduced maintenance No lubrication necessary.

Technical details

Application Efneo’s GTRO Gearbox is dedicated for all non-competition bikes like touring, city, e-bike, folding, recumbent, trike. It has been heavily tested in various conditions (on-road, off-road and laboratory tests, including winter tests). However, it has not been tested for competition MTB, downhill or dirt applications.

Gear ratioGTRO’s 1st gear is a neutral gear (1:1). Second and third gears are incremental. GTRO’s standard chainring is 28T.



Teeth equivalent for 28T



28T (physical chainring size)



40T (physical chainring size)



50T (physical chainring size)

Interface GTRO Gearbox is compatible with most bicycle frames using standard square tapered 4 flats BB’s with 68 mm or 100 mm wide BB shells, with English thread. BB shell diameter can not exceed 45,6 mm.

Gear shifting Efneo’s GTRO Gearbox is delivered with a dedicated trigger or grip shifter.

Rear transmission compatibility Compatible with any rear transmission  (derailleur, geared hub, single speed hub, rear motor) except fixed wheel. For internal geared hub, please check manufacturer’s specs for the smallest front chainring allowed.

* Comes with thumb shifter as standard

* 38T conversion kit includes chainring and bolts, all you need to convert any standard GTRO and increase all its ratios by 1:1.36

* Also available with grip shifter or for Brompton and other folding bikes