A Schlumpf Drive is a two-speed

planetary gear An epicyclic gear train (also known as a planetary gearset) consists of two gears mounted so that the center of one gear revolves around the center of the other. A carrier connects the centers of the two gears and rotates the planet and sun gea ...

assembly for use on bicycles and unicycles. It is distinct from other bicycle planetary gear assemblies in that it is located behind the

chainring The crankset (in the US) or chainset (in the UK), is the component of a bicycle drivetrain that converts the reciprocating motion of the rider's legs into rotational motion used to drive the chain or belt, which in turn drives the rear whee ...

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. *Speed Drive, this allows a 65% increase in the final drive (ratio 1.65). *High Speed Drive, this allows a 150% increase in the final drive (ratio 2.5). *Mountain Drive, this allows a 60% reduction in the final drive (ratio 0.4). *Reha Drive, this also allows a 60% reduction in the final drive (ratio 0.4). However, it is specifically designed for hand-cranked disability vehicles and requires less pressure for shifting. Schlumpf drives are currently used in some Pashley and

Moulton Moulton may refer to: Places in the United Kingdom ;In England *Moulton, Cheshire * Moulton, Lincolnshire **Moulton Windmill * Moulton St Mary, Norfolk * Moulton, Northamptonshire ** Moulton College, agricultural college ** Moulton Park, indus ...

bicycles, and in multiple brands of unicycle, primarily mountain unicycles and unicycles for distance riding.

History

The first Schlumpf prototype planetary gear drive was developed by Florian Schlumpf in 1988 in Switzerland. Production and development were soon established there. In 2004, the first Schlumpf hub designed specifically for unicycles went into production. Shortly afterward, a collaboration with

Kris Holm Kris Holm (born July 15, 1973) is a Canadian best known for riding a unicycle in off-road conditions. He has ridden since 1985 and is considered one of the pioneers of off-road unicycling, and is the world's best-known unicyclist. He is the founde ...

led to a

co-branded Co-branding is a marketing strategy that involves strategic alliance of multiple brand names jointly used on a single product or service. Co-branding is an arrangement that associates a single product or service with more than one brand name, o ...

mountain unicycle version that bore higher loads and no longer required an external torque lever. Since 2012, the entire range has been manufactured in Germany by Haberstock Mobility, following an agreed buy-out in late 2011.FlorianSchlumpf development history
/ref>

References

{{German bicycle manufacturers Cycle parts manufacturers Bicycle parts Engineering companies of Germany Epicyclical gearing Unicycling

History

See also

References