Schlumpf Innovations Gearing Systems

Swiss manufacturer Schlumpf Innovations produces two-speed, planetary gear-driven crank/bottom bracket systems. With a Schlumpf Speed Drive, Mountain Drive, or High Speed Drive, you can expand the gear range of a single-speed, fixed-gear, or internal gear hub-equipped bike while maintaining a clean look.

 

With Schlumpf's gearing systems, two gear ratios are available without the chain moving between gears, and there's no front derailleur, shifter, or cables to maintain or clutter up your bike. You simply shift with a quick heel movement against the push-button axle in the center of the crank arm. The gearing systems use a clutch plate design that won't slip under power and they require very little maintenance.

Cycle Monkey offers all three of Schlumpf's gearings systems: Speed Drive (1.65 overdrive ratio), Mountain Drive (2.5 reduction ratio), and High Speed Drive (2.5 overdrive ratio) in all the various configurations. We also have a longer axle version that is compatible with the 54mm chainline of the Rohloff SPEEDHUB 500/14. Crank arms are available in black or silver in a variety of lengths.

Schlumpf Speed Drive

The Schlumpf Speed Drive is ideal for town bikes: single speeds, fixed gears, internal gear hub bikes, or bikes with only a single, rear, derailleur. The close 1.65 overdrive ratio means shifts can be made more often and more comfortably. This is also the best Schlumpf model to combine with a Rohloff SPEEDHUB 500/14 for those applications in which the gear range of the SPEEDHUB 500/14 is not enough. It's also great for small-wheeled bikes to get a larger gear ratio without a huge physical chainring.

Key specifications and features of the Schlumpf Speed Drive include:

  • 1.65 overdrive ratio (similar to a front derailleur shift)
  • Small physical chainring and larger effective chainring size in overdrive
  • mode
  • Close range well suited for use with single speeds, fixed gears, internal gear hubs, and rear derailleurs
  • Splined chainrings available in 27-40T
  • 110mm BCD spider also available for standard chainrings
  • 110mm BCD spider version can be used with two chainrings
  • Optional trouser guard available
  • Offers 868% gear range when combined with Rohloff SPEEDHUB 500/14

Schlumpf Mountain Drive

The Schlumpf Mountain Drive is the best choice when you are looking for the lowest possible gear ratio. The wide 2.5 reduction ratio can offer an effective chainring size that is lower than any available chainring (depending on physical chainring selection). It also has the highest running efficiency of Schlumpf's offerings, making it the best choice for HPV's or other land-speed vehicles. It is not recommended for use with the Rohloff SPEEDHUB 500/14 due to conflicts with Rohloff's minimum gear ratio requirement.

Key specifications and features of the Schlumpf Mountain Drive include:

  • 2.5 reduction ratio
  • Large physical chainring and smaller effective chainring size in reduction mode
  • Offers lowest gear ratio option of Schlumpf gearing systems
  • Highest running efficiency of Schlumpf gearing systems
  • Possibility of an effective chainring size that is smaller than any available chainring
  • 110mm and 130mm BCD spiders available for standard chainrings
  • 110mm and 130mm BCD spiders can be used with two chainrings
  • Optional steel spider for heavy duty use on tandems and cargo bikes
  • Best when combined with a gear hub or rear cassette offering at least 250% range

Schlumpf High Speed Drive

The Schlumpf High Speed Drive is the best choice when you want to maximize your overall gear ratio and keep a small physical chainring. It is great for small-wheeled bikes to get larger gear ratios without a huge physical chainring. It is a popular choice for recumbents and trikes, usually combined with an intenal gear hub in the rear. It can also be combined with a Rohloff SPEEDHUB 500/14 for an extremely wide gear range.

Key specifications and features of the Schlumpf High Speed Drive include:

  • 2.5 overdrive ratio
  • Small physical chainring and larger effective chainring size in overdrive mode
  • 27T sprocket/ trouser guard comes standard (67.5T equivalent gear in overdrive)
  • 30 & 34T splined chainrings available (75 & 85 equivalent gears in overdrive)
  • 130mm BCD spider available for standard chainrings
  • Best when combined with a gear hub or rear cassette offering at least 250% range
  • Offers 1315% gear range when combined with Rohloff SPEEDHUB 500/14

Please contact us to learn more about Schlumpf and the best gearing system for your bike and riding conditions.

Schlumpf Drive Options
 

With a 1.65 overdrive ratio, Speed Drive is versatile for a wide range of single-speed, fixed gear, and geared bikes.

With a 2.5 reduction ratio, Mountain Drive provides the lowest possible gear ratio for super steep climbing.

With a 2.5 overdrive ratio, High Speed Drive maximizes your gear ratio while retaining a small chainring.

 

For more information, please contact info@cyclemonkey.com or (510) 868-1777
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