Huggacast 50: Jeremy Sycip shows the Schlumpf internally geared crank

When I was at Sycip Designs in Santa Rosa, Jeremy was in the midst of building up a bike with the Schlumpf internally-geared crankset. The Schlumpf has 2 speeds on a single chainring; you toggle from the 2 gear choices by tapping a button on the crankarm at the BB axis. This system is similar to the new SRAM/Truvativ crank for free-ride and downhill except the SRAM design uses a bar-mounted shifter and requires a specially designed frame.


My German is not too good, but this idea has been around for a long time. Illustration

I’m very interested in the Schlumpf for [the Modal](, as another mode. We’d considered using the Melvin to make it into a two-speed (for the hills), but just wasn’t down with that for travel.

wahrscheinlich haben Sie Recht..

.83er and dead baby joby just built up a long haul trucker with a schlumpf and a rohloff.  it’s got a pretty huge gear range.

it does require the bottom bracket shell to be modified.  not entirely onerous but something to be aware of if you’re going to modify a flexible bike like the modal.

if all you want is a two speed, maybe try something like another wheelset built around a bendix kickback hub or get val to wrangle you up one of his custom 2-speed fixed hubs.

Wouldn’t work for everybody… my heel already brushes the crank arm on every rotation. That little button would either disrupt my pedaling motion or be shifted by accident, which wouldn’t be so nice.


Ja, I vas tinking das as vell. Mein heels hit den crankarm too. Maybe nicht sehr gut fur us. 

(since Schlumpf is Swiss, this parody is meant to be in Schwitzerdeutsch, the Swiss-dialect of the German language incomprehensible to Germans.)

Engineered poetry in motion

I’ve been using a Schlumpf SpeedDrive on my Greenspeed Recumbent ( since 2006. Indispensable. And no, your heel doesn’t brush the button.

I team it with a Rolhoff 14-gear Speedhub   (



I have kept an eye on these for a couple of years now.  Seems like an interesting application for single speed mountain or CX bike to me.  Expensive as all heck…especially with the US dollar so depressed.

FYI The BB doesn’t necessarily have to be modified, at least one model of the Schlumpf uses a torque arm that clamps to a chainstay.

it looks like Schlumpf has new models coming out for 09:

Advertise here

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