Three remarkable innovations are transforming the mechanics of the common bicycle. In fact, these new technologies may be the most significant developments in bike engineering since the original "safety" bicycle was invented at the end of the 19th century.
Electronic shifting image courtesy of our friends over at cyclingnews.com
Given the infiltration of electronics into every aspect of our lives, the emergence of an electronic shifter is no surprise. Here's how it works: Instead of using a mechanical shifting lever, a button sends a signal to the derailleur and activates a small motor that provides a fast, reliable gear shift. A servo mechanism adjusts the positions of the front and rear derailleurs so they're optimally aligned, producing maximum power-transfer efficiency. Electronic shifting can take a wired form, where the shift up/down signal is transmitted via cables, or a wireless form that uses multiple frequencies. The downsides are minimal. The most obvious is that if your battery runs out, you're screwed. This said, Shimano estimates that the 7.4-volt battery in its Dura-Ace Di2 line of component shifters will last over 1000km per charge.
The other downside is price. The Di2 system costs $US2500, and it will likely be two years before the tech trickles into cheaper, mid-range kits. Nonetheless, cyclists are riding with electronic shifters today: George Hincapie rode a Trek Madone with electronic shifters in the 2009 Tour de France, and Trek already provides battery mounts and Di2 cable routing on its race-ready Madone frames. Campagnolo will release its electronic shifting kit in 2011.
The traditional chain is one of the biggest weak spots on any bike. Increased force on a link chain produces strain on the links themselves. Over time, these links break-and once they break, you're usualy hosed. Failure is accelerated by the dirt and grime that chains accumulate because of their much-needed lubrication. And constant wear and tear from grabbing and releasing gears doesn't help a chain's lifespan, either.
Trek's drivetrain belt looks eerily similar to some we've seen in LEGO kits.
Enter the belt drive, which increases the efficiency of a bike's power train while greatly extending its life. At its core, this is a simple piece of technology not unlike a conveyer belt. A smooth, contiguous piece of rubber or plastic-based material moves around two rotating gears. In early prototypes of bicycle belt drives, nubs down the centre of the belt grab onto gears, and an internal shifting hub changes the gears.
In addition to increased power efficiency, the belt drive doesn't need to be lubricated-there are no moving parts, and it's not likely to break for the same reason. How close are we to seeing belt drives? Close enough that Trek has already developed the prototype pictured on this page. The only real downside, aside from scarce availability, is that a purpose-built frame is required because you can't pop the belt drive off like you would on a normal bike.
Expect to see belt-driven bikes in mass production by the end of this year. It's an ideal fit for a low-gear city bike.
Continuously Variable Transmission
The biggest leap forward in bike design comes from a San Diego R&D shop called Fallbrook Technologies. Its innovation is the NuVinci transmission, a two-wheeler version of a CVT, or Continuously Variable Transmission, which already lends efficiency to hybrid automobiles.
On a traditional bike, you need to manually switch gears within a limited set of, say, 10 or 18 "speeds". But with a NuVinci transmission, you're given an infinite variety of gearing ratios-within a specified range, of course-to perfectly match your energy output to the incline of the road.
Video uploaded by imapodaddy.
CVTs use rotating and tilting balls positioned between the input and output components of a gearing system. This arrangement progressively varies the speed of the transmission, providing linear and essentially infinite gearing options. Compared to a traditional set of flat cogs, you also enjoy increased efficiency, as there is no loss of power during a shift.
You can buy a bike outfitted with NuVinci's CVT today from Ellsworth Bikes. Me? I'm going to wait a little longer-I want all three new technologies working in concert on the same ride.
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