Cyclists of the world unite! You have nothing to lose but your chains (and derailleurs)
By Michael BerkPosted 06.07.2012 at 5:46 pm 19 Comments
Summer's here and it's time to get back on the bike. We could have looked at a fancy new ultralight, but the NuVinci is the bike that's really going to shake things up. It answers a question you may not have thought to ask: what if you could pick up a new ride with a transmission that made sure you'll never be in the wrong gear?
A NuVinci bike effectively has an infinite number of gears. You can adjust it smoothly, without worrying about clicking into gears, to provide the precise right amount of resistance. You can start at a very low gear to pedal easily and then smoothly ramp up to a higher gear as you gain speed. And since everything is internal, repairs are rarely necessary. It's a revolution, really--one of the most fundamental changes to the bicycle in decades.
In honor of How It Works Month here at PopSci, please enjoy with us this elegantly done film explaining how a differential gear works. It dates from the 1930s, but BoingBoing reminded us how truly excellent it is.
Tiny bacteria may seem rather unintelligent, but a bacterial crowd can accomplish the Sisyphean task of turning microgears millions of times bigger than themselves. The microbes start out by swimming randomly, but occasionally collide with the spokes of a gear and begin pushing. Scientists from the U.S. Department of Energy's (DOE) Argonne National Laboratory and Northwestern University observed a crowd gather and push against the spokes.
For years, creating the gears and sprockets needed to make a microscopic robot has required the expensive and time-consuming process of silicon etching. Carving out each individual piece with a laser has made producing more than a couple of pieces prohibitively difficult and costly.
A team at Columbia University now seems to have found a way around that problem. By laying a thin sheet of metal over a special layer of polymer, the team has created nanogears that assemble themselves, opening the possibility of much faster, cheaper, widespread production.
How do you make a bicycle that never needs lube, never leaves grease on your pants, and always delivers smooth pedaling? Simple: Ditch the chain.
For its new Soho commuter bike, Trek replaced greasy metal links with a dry belt. Unlike other attempts at such bikes, the Soho is silky smooth to pedal. And it's the first to offer multiple speeds, using an eight-gear transmission inside the rear-wheel hub.
Microengineering: A new space-saving technique could make micro-gizmos much easier to build.
By Arthur FisherPosted 03.26.2002 at 2:12 pm 0 Comments
In 1869, French clockmaker Andr Guilmet conceived the idea of connecting gears
to the pedals of a bicycle and joining them to its rear wheel with a metal chain. The invention revolutionized the bicycle and, with it, transportation. Now researchers at Sandia National Laboratories have fabricated a tiny descendant of that early chain that saves space in microelectromechanical devices (MEMS) and which may prove far more revolutionary.