Bottom bracket gearing
 

Does anyone here run, or have run, a bike with a geared BB? What's it like? Who's famous for them? Seems like a neat concept, but not having any first hand I'll remain on the fence.

M.

The only one I know of is made by Schlumpf....Has a good reputation but I've never run one....I think fietsbob(a member here) has one on a folder or something.Maybe he will see this and comment.

Looked at adding a Schlumpf to my old 1x1,but stopped cold when I saw the price tag. :eek:

FSA makes one,but I can only think of one bike that uses it(Raleigh I2x8).

Truvativ also makes one,but it's designed for MTB use,is as expensive as the Schlumpf,and if memory serves you need a special mount on the frame.

Strida makes a 3spd,but only for their folders.

I've looked at them,and think they're pretty much a niche item. If they could make them fit in just the BB,so you could use any cranks,and could do something about the jumps in gearing(the Strida EVO 3spd is a better idea),they'd be much more practical.

I put the Schlumpf for Brompton Mountain drive in my M3L .. the big reduction gear is 150%

so the AW3 hub is run through twice.. a 50t acts like a 20t in low range..

but for real Bottom of the frame gearing you may look at the Pinion.

It has more in common with motorcycle transmissions than planetary variations of the old 3 speeds.

http://pinion.eu/en/ 18 speeds, frames are made around the gearbox, centered in the BB area, like

http://www.en.tout-terrain.de/bicycles/silkroad-xplore/

http://www.en.tout-terrain.de/bicycl...ricana-xplore/

the guys that developed it were with Porsche , I read.

Schlumpf has transferred the Manufacturing of his stuff across the border to Germany

as the CHF , home of the secret numbered bank account was stronger as the rest of the continent
was pushed into Austerity plans , which makes Swiss Exports over priced.

These are the only ones I am aware of. I have ridden a Schlumpf equipped recumbent and was very impressed with it, the price tag is what it is. You are paying for a limited production well made item. I have an FSA in the box that someone gave me, just haven't gotten around to putting it on a bike, not sure which one it is going on.

Aaron :)

Looked at the site for the FSA same 1.6X overdrive as the Schlumpf speed drive, but..

Chainring is 28t, vs the use of a 110 spider , so 34t or larger rings are possible ..

and the Schlumpf can use any crankarm 1 from a tandem kit , to get the pedal, RH/LH, threads
thats the Rt, of the front crank , + the left off a standard single crank
(they of course come with a set of cranks, you have choices)

the FSA is cable operated, so you have another lever on the bars..

vs just tapping the center of the crank with your heel, one side or the other..

Schlumpf High Speed Drive is the inverse of my mountain drive 2.5 x overdrive .. 27t/67.5t !