Review: FSA Metropolis Patterson transmission

By Justin Steiner

Sam Patterson may not be a household name to the average cyclist, but he’s had a great deal of impact on the cycling world. Patterson, the namesake of FSA’s Metropolis Patterson Transmission, co-founded SRAM back in 1986, where he designed the ubiquitous Grip Shift shifters. Since leaving SRAM in 2000, Patterson has spent countless hours designing and prototyping fun stuff in his backyard workshop. He now has his sights set on redesigning the bicycle drivetrain as we know it—this transmission is just the first step. Patents are pending on other designs, so keep your eye out for some interesting stuff from Patterson.

Patterson isn’t a fan of front derailleurs, due to their complexity and clutter, so he’s spent the last 20 years brainstorming alternatives. Design sketches of the Metropolis Transmission were first put to paperback in 2006, and from that point, Patterson began building rideable prototypes.

The Patterson is a two-speed crankset and bottom bracket unit similar in design and execution to SRAM’s HammerSchmidt and the Schlumpf Speed-Drive. Unlike the HammerSchmidt, which requires frame-mounted ISCG tabs, the Patterson is compatible with any standard 68mm bottom bracket shell. Installation is more straightforward than you might imagine, easily executable by a home mechanic with proper tools and moderate mechanical aptitude.


The Patterson Transmission provides two ratios, a 1:1 ratio and a 1.6:1 ratio (overdrive). The overdrive ratio is provided by four planetary gears, which run inside a ring gear, all housed within the drive-side crank. When engaged, these planetary gears drive the ring gear and accompanying chainring, 1.6 times faster than the cranks. In this overdrive mode, the stock 28-tooth chainring becomes equivalent to a 45-tooth ring, so it’s a pretty significant jump in gearing. Other chainring options, as well as Gates Carbon Drive cogs, will be available in the future. Crankarms are available in three lengths: 165, 170, and 175mm.

Patterson offers a very broad range of gearing as tested with a wide-range 11-32-tooth cassette and would be sufficiently wide with a 12-28-tooth road cassette for most on-road users and commuters. During my test, I spent much of my time in the overdrive ratio pedaling to and from work and around the city. Only on significant hills did I feel the need to bump down into low gear.

Shift actuation is performed by any indexed or friction front shifter, so compatibility is open to just about anything from integrated road shifters to thumb shifters. Shift action is swift and positive, up or down.



In many ways, the ultimate use of a transmission like this would be in conjunction with an internally geared rear hub, or even with a singlespeed—you’d have a normal “cruising” gear and a “climbing” ratio. In these applications derailleurs would be eliminated altogether, delivering a clean aesthetic and requiring less maintenance.

There are a few minor drawbacks. In overdrive, a light clicking or freewheeling sound is emitted as the chainring spins faster than the cranks. I didn’t find this annoying, but some users might. Also, there are frictional losses in all of the two-speed cranksets on the market; it’s simply the nature of the beast. That said, FSA worked hard to minimize friction, and I didn’t notice any on the road. Lastly (and sadly), this crankset isn’t designed for the muck and abuse of off-road use.



It’s easy to see this transmission being readily adopted on loads of city and commuting bikes for its high level of functionality, low maintenance, and clean appearance. The $300 price tag isn’t out of line when you consider you’re replacing a crankset, bottom bracket, and front derailleur.

Made in Taiwan.

Weight: 1,763g.





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