The bicycle, one of the world’s most resolutely human-powered machines, will soon join the long list of devices that have switched from the manual to the electronic when a new gear system makes its debut tour of California. Although the battery-powered derailleur by Shimano promises to bring ease and accuracy to changing gears by enabling riders to shift with a light touch to two electronic switches, traditionalists worry that it may erode the basic tenets of the sport.
Whether the gear system becomes the next iPod and redefines bicycle technology or ends up as the sport’s version of the eight-track tape will hinge on a number of factors, the most obvious being performance, reliability and cost. A full set of Shimano components, known as the Dura-Ace Di2 7970, with electronic gears, will cost about $1,250 more than the newest mechanical version, which sells for about $2,750 (around Rs1.35 lakh). Upgrading an existing Shimano system is expected to cost about $2,200. The system will fit on to nearly all racing bicycles.
Chain reaction: (From top) Shift and brake levers; a rechargeable lithium-ion battery; a derailleur adjuster with a battery-level indicator; and a rear derailleur
Electronic gear-shifting technology has spent a long time in development. Prototypes of French company Mavic’s first system, the Zap, made a cameo appearance at the 1992 Tour de France and the company introduced its second attempt, the Mektronic, in 1999.
For much of this decade, both Shimano, which dominates bicycle parts the way Microsoft dominates computer software, and its venerable Italian competitor Campagnolo occasionally tested prototype systems on the bikes of pro riders. More often than not, the prototypes were devoid of trademarks, to limit embarrassment if results proved as unfortunate as the Zap.
This year, Giant, the largest bicycle manufacturer in the world, will offer a bike designed to use only electronic parts for about $14,000, which includes the cost of Di2. If consumers fancy it, it will likely follow the pattern of other new electronics and drop significantly in price over time.
Bob Stapleton, owner and general manager of Columbia High Road, one of the three teams using Shimano bikes at California, says many of his riders had doubts about using bicycles that could literally run out of power. The Di2 system has no manual override if its battery goes dead. That can be an irritation or a disaster, depending on the terrain and what gear ratio the bike is stuck in. Shimano estimates the battery will last for about 1,000 miles per charge.
The Shimano system shares the basic design of mechanical derailleurs—that is, a parallelogram that moves the chain back and forth—and in the rear, two spring-loaded wheels to keep the chain taut. Two paddle-shaped electronic switches that sit behind the brake lever allow riders to shift gears. Tapping either paddle lightly in Di2 sends an electronic signal through a wire to a small motor inside the derailleur, moving the body and thus the chain by turning a worm gear. Even Devin Walton, a spokesman for Shimano, acknowledges that when it comes to the rear derailleur, there is little or no difference in shifting between the electronic and comparable mechanical offerings of the company.
The gains are more obvious, however, with the front derailleur, which moves the chain between the two large, toothed rings on the bicycle's crank.
That is partly because the electronic front derailleur is able to make constant readjustments to reflect changes in the chain's position caused by shifting with the more frequently used rear derailleur. That allows the electronic front derailleur to use a more efficient shifting mechanism, one that would drive riders to the point of distraction with fiddly readjustments on a mechanical system. The action of the electronic system is so effortless that compared with mechanical levers, it leaves users feeling almost disconnected from the bike. ©2009/ THE NEW YORK TIMES