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FSA Unveils Metropolis Patterson Transmission Internal Geared Crankset for Commuters

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SEA OTTER CLASSIC 2010 – FSA had one of the few, perhaps only, real game changer* product release at Sea Otter.  Debuting under their Metropolis line of street products, their new Patterson Transmission crankset uses an internally geared planetary drivetrain that provides an effective 42T chainring to complement its physical 28T ring.  The big news?  It requires no frame mounts or modifications.

What this really means is that come NAHBS, Oregon Manifest and Int’l Framebuilders Expo (formerly the San Diego Custom Bicycle Show) next year, I’m betting you’ll see this on many, many bikes.  Why?  Because combined with an internally geared rear hub like, oh, say Shimano’s forthcoming 11-speed Alfine, you could get a 22 speed bike with nary a derailleur in sight!  If FSA makes it available with a carbon belt drive gear, which FSA mentioned is in development, you’d be looking at a relatively bomb-proof commuter and city bike drivetrain that would appeal to a lot of folks.

Sound interesting?  Click more for details and photos…


Like Truvativ’s HammerSchmidt, the Metropolis PT crankset uses internal gearing to change the drive ratio from 1:1 with the 28T to 1.6:1 to simulate a 42T ring, and shifts are instantaneous and effortless, even under load.


FSA’s version is meant for commuter-type use only, not mountain biking.  The only requirements for use are a standard 68mm bottom bracket shell and downtube front derailleur cable runs.


The cable runs down the tube and directly to the inside of the crankset.  Normally, the ring runs in cadence with the cranks for lower gearing.  When shifted, it essentially engages the pawls that are turn the internal gears and provides for 1.6 gear turns per crank rotation.

Where HammerSchmidt relies on ISCG tabs to mount to the frame so it doesn’t rotate, the Metropolis PT setup simply has a plastic arm that swings into the chainstay to prevent rotation of the entire unit.  It’s a simple solution that opens up a lot of opportunity for people to install on existing frames.  In fact, FSA says installation is so easy, an experienced mechanic (home or shop) could probably put one on and have it working in about 20 minutes.


Because the internal pawls retract completely when disengaged, the system runs very quiet and the unit will shift with pretty much any two speed shifter.  FSA did caution against using it with shifters that snap the gears too quickly, though, as they could basically trick the system into not shifting or something like that.  Sounds weird, but they’ll have a compatibility chart when it becomes available.

Speaking of which, it’ll be spec’d as OEM on complete bikes first, then hit the aftermarket at the end of the year.  Look for MSRP to be around $300.  Weight is around 1,500g (about double high-end racing cranksets, but not too far off low-end commuter sets).

FACTOID: The Patterson Drive is the brainchild of Sam Patterson, who worked at SRAM for 14 years and helped develop the original Grip Shift products. He doesn’t like front derailleurs.


The brushed aluminum finish of the PT crankset will match the Metropolis mustache handlebar and a new matching stem and seatpost (not shown).

*You could argue that the Shimano’s 3×10 Dynasys or SRAM’s 2×10 X0 and X9 groups are gamechangers, but in our opinion the 3×10 is an evolution, a good one, and the 2×10 was all but foreseen for those two groups having already been announced on the X7 group.

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14 years ago

Very cool development for the city-cycling crowd! But please, dont bother with a belt drive version. Instead, develop a “Metropolis” chaincase so a standard chain can be used.

Belt drive is cool for sure, but it it very expensive, requires a special frameset, and does NOT offer longer wear than a regular 1/8″ chain that is inside a chaincase.

14 years ago

Why not belt drive? If a special frame set is required (which I agree it is, I already own one and have another on the way), why not start producing all frames with this feature. A belt drive frame can be equip with a chain drive so then you could go either way.

I really think a 22 speed internal system with a belt would be a very nice commuter or touring bike that would be quite reliable as well.

Just my .02

14 years ago

It’s a Schlumpf Speed drive with a cable actuator ..
Florian’s Products are all ready in production 1.6:1 overdrive
available manufactured in 27t , and with a spider to fit , say, a 38t to pair with 16t cog on Rohloff hubs .

Admittedly, Asian contract factorys will have lower labor costs than Switzerland.

Schlumpf Innovations also manufactures a 2.5:1 over drive, and a 1:2,5 reduction gear .

.. and a 2 speed Unicycle hub..

13 years ago

Can anyone comment if the Metropolis set-up would be compatible with the eccentric bottom bracket arrangement used on some Nexus/Alfine IGH bikes (e.g. Felt X-City 1)? I kinda suspect the Metropolis combined with the Alfine 11-spd might be overkill, but Metropolis with an Alfine 8 could be quite nice. I acknowledge the Alfine-11 sounds like a much nicer-engineered unit than the 8

12 years ago

i have a better idea. how about a bike with drives on both sides where both chainwhees freewheel in both directions?. when one chainwheel is locked the other powers the bike in track bike mode. if neither chainwheel is locked you have a freewheel

to wit one would have a trak bike where one could shift to two speeds or to freewheel-3positions.
email me for details

ted kulhan
ted kulhan
12 years ago

Having trouble finding Schlumph 2 speed unicycle hub. Help Thanks ted

Doug Hakd
Doug Hakd
12 years ago

Metropolis needs to make a more bomb proof version for mountain bikes. I am tired of continually bending back my rear deraileur and buying new deraileurs and dropouts. Rocks and brush are not kind to flimsy external shifters. For road bikes, internal drives are nice. For mountain use, internal drives are long overdue.

11 years ago

New transmission CVT design by BitRaptor. Is a continuously variable transmission CVT gear only (the only one functional in the world), very compact and lightweight, and which could replace the current systems both for efficiency, simplicity and not least the costs.

Because this CVT work only with pinions is better the all other systems by efficiency and high torque transmission.

In the web page you will find more explanations, drawings and a short video of a basic prototype.

The first prototype will be ready for tests during this year.

Other possible applications CVT design by BitRaptor are: bicycles, motorcycles, cars, automobils, boats, gearboxes, electric motors, steam and wind turbine, as well as a large number of industrial or agriculture applications whenever is necessary some adjustment of the gear ratio.

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