As you probably know, the Efneo gearbox is not the first company to turn to planetary gearing as a replacement for a front derailleur. Truvativ tried it with their HammerSchmidt, FSA offers it in their Metropolis Patterson Transmission, and other companies like Schlumpf have packed two gears into one for years. So what makes the Efneo crankset unique? Instead of the usual gear with an overdrive function, Efneo has managed to cram three different gear ratios into a compact crankset. Since the project was first announced, and launched on Indiegogo, the gearbox has attracted a lot of attention, but not enough funding to reach its goal.
To get there, Efneo is offering a secret deal that really isn’t much of a secret anymore…
If you’re not familiar with the concept, a planetary crank system works by running the chain around a single chain ring. Shifting the gearbox changes the gear ratio internally through a system of planetary gears which are basically exactly as they sound: a bunch of little planet gears rotating around the central “sun” gear. Changes in the planet gears cause the outer ring to spin faster or slower depending on the gearing. The Efneo has three different ratios which are the equivalent of running a 28/40/50t triple crankset with the first gear running 1:1, the second a 30% increase, and the third increases the gearing an additional 25%. The result is a triple without the problems of a typical front derailleur but more importantly an ideal chainline as well as the ability to run a ‘3 speed single speed.’ Other advantages include shifting under full load and shifting while stopped.
Designed to install on any frame with a 68mm BSA bottom bracket shell, the Efneo can be retrofitted to many bikes though the company specifies it’s not for “extreme mountain biking.” The weight for the actual crankset isn’t listed, but they claim it will add 200-300g over a quality aluminum triple drivetrain. Available in 170 and 175mm crank arms, the Efneo will have its own paddle shifter that controls the gearbox with a single shift cable.
Another crowd funded bicycle project, the compelte Efneo gearbox starts out at $230 for the early adopter pack through Indiegogo. The kit includes the crankset, bottom bracket, shifter, and cable which is everything you will need to install it on your bike minus the tools. However, if you select the “Secret Perk” on the backer page you will get your gearbox for just $185. Not a bad deal to try out an entirely new drive system for your bike.