Hey fixed-gear riders — get ready to weep. You know how you spent all that time and money building the most minimal, clean-lined machine possible? Well take a look at the Alpha bike. It’s so clean it doesn’t even have a chain.
The Alpha bike is the product of a year’s work by five mechanical engineering seniors at the University of Pennsylvania, and it manages to pack in enough tech to be the KITT of bikes, but with the looks of a stripped-down “fixie.”
Let’s start with the frame. Ornate lugs? It’s got ‘em. The lugs are all CNC-machined from aluminum blocks, and then bonded to carbon fiber tubing. Thus you get the look of a classic lugged steel frame but with high-tech materials.
Through this frame run all kinds of gear. In fact, I wouldn’t be surprised to see Bruce Willis (as John McClane) crawling through the ductwork. Electronic and gear cables run from the handlebars to the bottom bracket and rear wheel, and a belt drive is threaded through the chainstays. In fact, calling them “chainstays” seems a little weird.
The transmission is also fully custom built, with a mixture of self-lubricating bronze, steel, aluminum and a titanium clutch plate sitting inside the bottom bracket. The clutch is electronically actuated by a button on on the bars and switches between fixed and freewheel drives.
The handlebars are carbon fiber wrapped around a plastic tube, kind of like making a piñata with a balloon, newspaper and glue, but without bursting anything afterwards. The plastic is kept in to make cable-routing easy. Set onto the top of the bars is a small LCD screen that acts as a cycle computer, and this stores its data on an SD card for easy removal.
Finally (and somewhat weirdly) comes the front brake. This too is minimal, and the cable runs through the frame. But it is a drum brake, aka a pull and pray brake (I just made that name up, but it seems appropriate). Drum brakes are found on old granny bikes and they really don’t work very well. They’re also heavy. The hub also has a dynamo to power the electronics.
The Alpha really is a weird machine, with those huge lugs, granny hub and high-tech everything. Totally eccentric — just like pretty much every home-assembled fixed-gear bike out there.
Alpha bike project [Alpha Bike. Thanks, Geoff!]
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