Schlumpf Drive


A Schlumpf Drive is a two-speed planetary gear assembly for use on bicycles. It is distinct from other bicycle planetary gear assemblies in that it is located behind the chainring rather than in the rear hub. A push-button on each side of the axle allows the rider to switch between high and low ratios. These are operated by the rider's heel.
Schlumpf Drives are primarily used as an alternative to multiple chainrings. Four models are currently produced, with differing ratios from pedal revolutions to chainwheel revolutions.
Schlumpf drives are currently used in some Pashley and Moulton bicycles.
Schlumpf products were initially designed and manufactured in Switzerland. They are now manufactured in Germany by Haberstock Mobility.