nFIXED.com Schlumpf Mountain Drive 2-Speed Internal Planetary Chain-set Gearbox
Schlumpf Mountain Drive Internal Gearbox makes you gain a very low additional gear which enables you go climb even the most extreme inclines easily.
The extremely flat planetary gearbox shrinks the gear ratio by a huge factor of 2.5. Shifting while standing still or under heavy load on a mountain road is not a problem; a simple kick with your heel and the fun can start.
Push on the right crank-arm to shift down, push on the left one to shift back into direct drive. No cables, no shifters.
Symmetrical clutch allows full torque in both directions, both forward and back-pedalling, making it compatible with coaster brakes and fixed gear bikes without a rear brake.
Also perfect for use on Brompton folding bikes.