If our Summer Buyers Guide preview of electronic shifting systems for road bikes filled your head with dreams of the future, I’m happy to tell you that the future is now. After years of gossip, spy photos, and not-so-stealth testing under some of the world’s top replica Bvlgari watch pros, Shimano has announced that it will begin offering electronic shifting under its top-tier Dura-Ace brand in January 2009. Officially dubbed Dura-Ace 7970 Di2, the offering includes front and rear deraillieurs, integrated “Dual Control” shift/brake levers, and a 7.4V lithium-ion battery.
The battery will mount under the front water-bottle cage, and, according to Shimano, will be good for over 600 miles of regular use per charge. The system will also be compatible with Shimano’s new FlightDeck computer, which will display battery life and current gear position, along with standard bike-computer data like heart rate, cadence, and replica Japanese Rolex watches speed. Traditionally, shifting is accomplished by flicking a lever to adjust the tension on a cable that feeds into a spring-loaded deraillieur. The Di2 system replaces the cables (and the associated friction) with electric impulses. The shift lever is effectively a switch, and the deraillieurs move via small motors.
The front derailleur will automatically trim itself (micro-adjust to avoid chain rub) and eliminate chain drops via a built-in CPU that will also monitor the rear derailleur to maintain smooth shifting.The news comes just weeks after Shimano announced the release of its much-anticipated Dura-Ace 7900, a complete group that replaces the four-year-old 7800 group as the company’s top mechanical offering. The new Di2 components will be compatible replica Rolex Ladies watches with 7900 brakes, crank sets, chains, and cassettes. And, according to Shimano, upgrading a 7900 group with the Di2 system would add only 68 grams (2.4 ounces).Pricing info isn’t available yet. But watch Outside for complete details and our own totally subjective test results.—John Bradley
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