Chances are that not many people remember the single chain retro-direct drive for bicycles — unless you’re a very serious bike historian. This late 1800’s French bicycle chain drive is a two-gear system that requires no need for a gear shifter, you simply have to pedal backwards.
Anyone who rode a bike as a kid remembers backwards peddling when you’re going down hill, it had no real purpose other than being fun. But with a retro-direct drive on your bike the backwards motion is essentially first gear, while traditional forward pedalling would be second gear. This type of bike drive system became unnecessary once more modern gear systems came into fashion, but it still looks like it’s a pretty simple way to get some extra boost without requiring a multi-speed bike.
Interestingly, the original retro-direct drives were reversed, you would pedal backwards if you needed more power and forward for easier riding. However modern bikers have opted to reverse that. Citing the difference in modern bike design from 1800’s bike design and the intuitive nature of pedalling backwards while cruising or going down hill. Personally it also seems like pedalling backwards while going uphill would feel awkward and uncomfortable, as well as looking pretty strange.
Here’s a brief video showing a modified bike with a retro-direct drive in action:
And If you’re a bike nerd you can go here and learn how to get the 3D printed parts to convert one for yourself. Just start by downloading and filling out a simple PDF form. Designer Scott Mayson will send you a plastic guide that will help you determine where to install the special retro-direct drive wheel mount. Once you send him back the dimensions of your bike he will design the stainless steel parts and send you a link via Shapeways. Have your parts printed out in 420 stainless steel and sent to you and then you can finish off your bikes customization.
Considering the very small pool of bike enthusiasts who would be interested in a strange bike conversion like this it’s pretty amazing how polished and well-designed the 3D printed parts are. This is a project that would simply not be possible without 3D printing. While, yes, someone would have been able to design the parts, manufacturing them with traditional methods would have priced this far out of most people’s budgets. But being able to 3D print parts to order has allowed hipsters everywhere to do silly things to their bikes and not have to go broke while doing it.
