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.

Product gallery

Technical details


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 ratio

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

Gear Ratio Teeth equivalent for 28T
1st 1:1 28T (physical chainring size)
2nd 1:1,43 40T (physical chainring size)
3rd 1:1,79 50T (physical chainring size)


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, grip or bar-end 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.

Bike types

GTRO for Trikes & recumbents

GTRO is a perfect choice for any trike or recumbent for three reasons.

Firstly, it’s even more important to be able to downshift to the 1st gear after stopping on a recumbent than on a standard bike.

Secondly, keeping the chain tension is much easier with a single front chainring than with 2 or 3 chainring crankset.

Thirdly, it’s a safety matter. When things go wrong and you hit something, the bom is broken, it’s much safer to have a GTRO with its chainring fully covered than a bare chainring that comes with most standard cranksets. It can make a big difference.

GTRO for E-bikes

Rear-wheel electric motor e-bikes are popular in urban/city segment. They usually look more elegant and sleek than mid-drive e-bikes.

Efneo’s GTRO paired with a rear-wheel motor makes a bike practical, stylish and maintenance-free. Three gears are just enough for urban applications. First gear to start (even uphill), second to accelerate or cruise, third to ride at top speed with an acceptable cadence.

There are various manufacturers collaborating with Efneo and testing GTRO on their e-bikes with very positive feedback!

Our objective is to make GTRO the first choice for this segment.

To give you a better idea of how exploding this market is – according to eCycleElectricConsultants 34 million e-bikes were sold worldwide in 2017, mostly in China and Europe.

GTRO for Folding bikes & e-bikes

Folding bikes segment belongs to the fastest growing in the cycling industry. Folding e-bikes are becoming a first choice of transportation for modern city dwellers in crowded European cities.

Efneo’s GTRO is a perfect match for folding bikes & e-bikes. All small-wheel bikes are facing the same challenge – at high speed, the chainring quickly becomes too small and the cadence skyrockets. On the other hand, front derailleurs are too spacious to be used and only small-range rear derailleurs can be applied, due to bike’s small size.

With the GTRO a bike’s designer gets much more flexibility. The physical chainring (or beltring) is small, while virtually it gets very large on a 3rd gear. With a folding e-bike, no rear derailleur is necessary to make gear shifting possible.

We are showing GTRO on Strida and Brompton, two top brands with which GTRO is now technically compatible. For both bikes GTRO offers better gear ratios, shifting & ride comfort and (as far as we know) higher reliability than original gear systems used on these brands.

Our objective is to make GTRO the first choice for all mid- and high-end folding brands on the planet.

GTRO for Urban bikes

Urban bike is a category for which gearboxes (like our GTRO) were made. Urban bike users and manufacturers do not favor derailleurs. Efneo’s GTRO is sleek, elegant, practical and comfortable.

Efneo’s GTRO design fits modern urban bikes perfectly.

Unlike rear wheel e-bikes and folding bikes, front gearbox (like GTRO) will never be a first choice for urban bike designers (mainly due to its price), but we want it to be an attractive option for OEM designers and retail upgraders.

GTRO for Touring bikes

A touring bike needs a vast gear ratio. That is why it usually uses both rear and front derailleurs. In the past, it used to be 3×8, now it’s rather 2×10 or 2×11. The reason for migrating from 3 to 2 chainring on a front crankset is that nobody really likes front derailleurs. Frankly saying, most people hate it.

Howerver, they still need it. Large rear cassettes like 11-42 have less around 400% gear ratio, which is usually too little for a real touring bike.

A rear cassette combined with GTRO offers all of the best from both worlds of gearboxes and derailleurs. GTRO adds the ability to reduce to the low gear after stopping and eliminates chain skewing or chain dropping. And you should feel how it upshifts when accelerating – nothing compares to this!

Moreover, you can use even the largest rear cassette and still be within the range of your derailleur’s cage. It also makes the bike designer’s work much easier.

GTRO for Compatibility with belt systems

One of the trends in the cycling industry is the growing popularity of belt systems. Unlike a chain, a belt is silent, clean (does not need lubrication) and more efficient energetically.

Moreover, if one wants a rear-wheel engine e-bike to be geared, front gearbox like GTRO is the only option. And most e-bike motors today still need some gears, at least when starting and at top speed.

GTRO is now offered with a 130BCD adapter that fits standard belt front sprockets from industry leaders like Carbon Gates or Continental. It can be also used for Strida, which always comes with a belt as a default option.

How to install


Click here to go to the manual section. You’ll see how to install the gearbox, how to change the shifter or shifting cable etc.

Check before you buy

Click here and read carefully how to check your bike’s compatibility with the Efneo’s GTRO Gearbox.

Testimonials and reviews

Check out what wrote about us

Check out what wrote about us

Check out what trikeasylum wrote about us

Check out Chris’s opinion

Chris review


So, I’ve put about 500 miles on the gearbox and i can say that it was totally worth the wait. I am including some pictures of my rig. Right now I am riding a Surly Big Dummy as a daily commuter. I live in the NC foothills and need to transport a fair amount of gear on a daily basis. For the drivetrain, I wanted something that was low maintenance…no derailleurs. The rear hub is a Nuvinci N360 which pairs well with the Efneo gearbox. With 3 gears up front and a CVT in the rear I have an almost infinite range of gear ratios.

The Efneo gearbox was easy to install, about 10 to 15 minutes. Shifting is super smooth and my top speed has increased by about 25%. One of my favorite things about this crank is that the physical 28T sprocket provides a huge amount of chain wrap. This means I am driving more power to the pedal even when I drop to the 40T and 50T settings. This will definitely be a must have for all future builds. let me know if you would like any other photos or testimonials.

Regards, Christopher

Check out what Blue Heron wrote about us

Check out what Bentrideronline wrote about us

Buy Efneo’s GTRO

30-day Money Back Guarantee for all GTRO models. No questions. If you don’t like it, we will pick it up on our cost and give you a full refund.

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If you are a bike dealer and you want to sell Efneo's GTRO, please e-mail us at fm(małpa) to get a special dealer offer.