Shimano has announced the highly anticipated electronic road component series, DURA-ACE with Di2 technology. The products, due in January, will be compatible with the new mechanical DURA-ACE 7900 series. Di2 stands for Digital Integrated Intelligence.
This innovative shift technology is still based on the Shimano Index System. The big difference is that in this case, the shifting action is provided for by electronics instead of mechanics.
This electronic shifting system has been tested extensively over the past two years by several professional riders in all weather and surface conditions.
DURA-ACE 7970 series consists of Dual Control Levers, electronically operated front and rear derailleurs and a battery kit. For the other components, like crankset and brakes, one can rely on the products taken from the new mechanical DURA-ACE 7900 group.
Dual Control Levers
Shifting is executed by simply pressing the button. No power is needed anymore to shift, which gives important advantages since it is easier now to always keep a tight grip on the handlebar and to keep your concentration on riding instead on shifting. The shift system allows accurate and effortless shifting in difficult circumstances like cold hands or when you are completely exhausted. Furthermore, the shifting performance will never be affected by contaminated or stretched cables since the shifting signal is transferred electronically.
The operating buttons work similar to mechanical Dual Control Levers so you don’t need to re-program your mind for a new system. The ergonomic bracket shape provides a greater degree of ergonomics and control for a variety of riders. An optional satellite switch allows shifting from multiple positions on the handlebar.
The Dual Control Levers have been provided with a reach adjustment mechanism which is an ideal feature for people with smaller hands. Furthermore, they are compatible with the new FlightDeck computer SC-7900 that measures data such as heart rate, altitude, cadence, gear position, a battery indicator and much more. FlightDeck works with coded wireless signals that prevent interference from other electronic units. The new FlightDeck can be used to make a wireless connection with a PC to analyze riding data (software is included), with reserving a potential for functional upgrades through the PC.
Just pushing the button will shift the front derailleur completely effortless and smooth, even under high load. An additional feature, much appreciated by Shimano's test riders, is the automatic trim function. The chain guide moves automatically in response to the setting of the rear derailleur.
Also the rear derailleur offers remarkable quick and smooth shifts. It has a wide gear ratio (11-27T compatible) and the electronics are well protected from heavy impacts such as crashes. The rear derailleur features a carbon pulley plate and titanium B axle for increased weight savings.
DURA--ACE Di2 uses a long-life 7.4V Li-Ion battery that is compact and powerful. Excellent reliability and a long lifetime has been proved through repeated field tests in various riding conditions over the last two years. The battery is very easy to mount and remove for charging and it fits any kind of road bike.
The shifting system is not wireless since that would need additional power (and a heavier battery).
DURA-ACE with Di2 technology contributes to Time Trial and Triathlon riding by its multi position shifters. It allows riders to shift while braking, by enjoying an effortless operation even when riding in the aerodynamic position.
Additional to the regular package, a Dual Control Lever ST-7971 with electronic shift buttons for time trial and triathlon usage is introduced. The carbon brake lever has been developed with a reach adjustment mechanism to fit all hand sizes. This Dual Control Lever is compatible with the new FlightDeck computer SC-7900.
Finally, also an electronic satellite switch SW-7971 will be available that can be integrated into time trial handlebar extensions. The shift wires can be guided through the bars for optimal aerodynamics.
More information about the new Dura-Ace 7900 and 7970 series can be found on http://www.dura-ace.com