I like to mention bike content in general design magazines when I see it, so I want to point you to a Dwell blog post about handmade bicycles. The post dates back to February, but it was new to me when I discovered it today, so I assume some of you missed it as well. The rear dropout shown here from a Vanilla road bike is just one of the detail shots you will see in the post.
The Trailcart has been spreading around the web since it appeared on Treehugger and Gizmodo. This pedal powered vehicle with independent four-wheel drive was designed by hobbyist Frank Fraune of Germany. The machine, which uses a Shimano Nexus 8 speed transmission, has up to 400mm of axle displacement. After looking at the pictures on the Treehugger post and in the Trailcart Gallery, all I can say is that I would love to try this thing out. If I did get a chance to ride it though, I would probably leave my team kit in the closet.
Ari of the Bits and Bikes blog has a question/challenge for all you designers and engineers who might be reading: Can you build a fixed-effort bicycle? The idea, which he is calling “NuFixie”, is to build up a bike that uses the NuVinci CVP hub, while controlling the gear ratio automatically based on sensor input measuring chain tension. He is looking for feedback, so leave a comment here or at his post if you have anything to say about his idea or about any other constant effort bicycle transmission concept. His post makes me want to go back and review the discussion of nonpositive drives and variable automatic transmissions in “Bicycling Science”. That book is always a great source on such subjects, but it worth keeping in mind that quite a bit has happened since the 80s. Some ideas that were not really practical at the time may become more feasible as new technologies emerge. In other words, don’t rule an idea out just because of obstacles in past attempts to make it work.