AndreZA Posted August 1, 2008 Share from http://www.velonews.com/article/81107 Shimano's electronic Dura-AceBy Lennard ZinnPosted Aug. 1, 2008Article ExtrasPhotoshttp://www.velonews.com/files/images/Di2_GROUP.Teaser.jpgDura-Ace Di2Shimano has formally announced plans to release Dura-Ace Di2, a new electronic shifting option for the all-new 7900 series Dura-Ace, in January. Comprised of dual control shift/brake levers, front derailleur, rear derailleur, a wiring harness and battery pack, the new Dura-Ace Di2 7970 components integrate with components from the upcoming 7900 series Dura-Ace group, while adding a total of only 68 grams. Electrically-actuated shifting eliminates cable friction and contamination. The shifters are now merely switches, which also allows for creative placement of optional remote shifters while also reducing the weight and profile of the main shifting units. For example, a rider could place remote switches out on the ends of aero bars as well as on the top of drop bars near the stem. Derailleur movements are computer-controlled and servo motors in both front and rear derailleur create synchronized shifts. http://www.velonews.com/files/images/ST_7970_01.Thumbnail2.jpgThe Di2 shifter: Lighter and sleeker profileST-7970 Dura-Ace Di2 Dual Control LeversBy eliminating mechanical shifter parts and using unidirectional carbon fiber brake lever blades, the new Dual Control lever is 155g lighter than the mechanical version. The levers are slimmer, and the ergonomics are further refined for a comfortable grip. Wiring HarnessExcept when it comes to downloading the on-board computer to a PC, the system is not wireless. It powers each derailleur through a wiring harness rather than adding the complexity of wireless transmitters and receivers. To have been wireless, each component would have required a separate battery, which would have added weight, and each receiver/transmitter would have consumed battery life at a higher rate. The shifter wiring harness accepts an all-new FlightDeck computer (SC-7900). The new FlightDeck features heart rate, altitude, grade, cadence, estimated caloric consumption, gear position, and battery life and is directly downloadable data via a wireless connection. http://www.velonews.com/files/images/RD_7970.Thumbnail2.jpgThe Di2 rear derailleur doesn't look like those on older electronic systems.RD-7970 Dura-Ace Di2 Rear DerailleurLike the 7900 mechanical derailleur, the 7970 has a new carbon fiber rear pulley cage, and the new design is compatible with wider-range cogsets, accommodating up to 27 teeth. Driven by a servo motor instead of a cable and spring, shifts are identical and precise due to the computer control unit analyzing each shift. The rear derailleur has a similar profile to standard rear derailleurs, rather than incorporating an oversized housing containing a reciprocating notched bar driven by the upper jockey wheel, which provided shifting power for Zap and Mektronic. Already less vulnerable due to its shape, Shimano built a mechanism into the rear derailleur that allows it to move inward under impact to reduce the potential for damage in the case of a crash. After being bumped inward, cycling through the shifting a couple of times automatically re-synchronizes the shifter and rear derailleur. http://www.velonews.com/files/images/FD_7970.Thumbnail2.jpgThe Di2 front derailleur is the brains of the operationFD-7970 Dura-Ace Di2 Front DerailleurThe front derailleur is the ?brains? of the system. This is a departure from Mavic Zap and Mektronic systems that preceded it; these had cable-actuated front derailleurs. The integrated ultra-compact CPU not only ensures shifting precision for both the front and rear derailleurs individually, but also monitors the position of each. The front derailleur tracks the chain and requires zero manual trim while maintaining shifting speed. The front derailleur logic also performs the inward shift from the big chainring in two split-second movements to eliminate chain drop. SM-BTR1 Dura-Ace Di2 Battery PackThe 7.4V, high performance Lithium Ion battery is designed to deliver reliable, long life even in the worst conditions. In conditions requiring consistent and frequent shifting, the battery is capable of 1000 kilometers of use. That?s not much relative to the battery life in a bike computer, but fortunately, this battery is rechargeable. Lithium Ion technology is lighter, more compact and better performing than other battery types. Shimano Dura-Ace Di2 7970 SpecsST-7970 Dura-Ace Di2 Dual Control Levers● Unidirectional carbon fiber lever blades reduce weight without loss of durabilityhttp://www.velonews.com/files/images/ST_7970_02.Thumbnail2.jpgThe Di2 shifter: An ergonomic redesign● Shifting positions mimic Dual Control with the ease of an electric switch● Titanium clamp and fixing bolt● Enhanced perch shape is more comfortable over longer distances● Integrated reach adjuster provides a custom fit for even smaller hands● Shift impulses transmitted in fractions of a second● Revised brake cable pivot location provides better braking modulation● Optional satellite shifter● Wiring harness is FlightDeck ready● 255g RD-7970 Dura-Ace Di2 Rear Derailleur● Carbon fiber rear pulley cage for lighter weight without loss of durability ● New geometry allows for use of 27 tooth max cog ● Servo saving feature allows derailleur body to move inward on impact to reduce or eliminate damage to the component and servo motor ● 225g FD-7970 Dura-Ace Di2 Front Derailleur● Integrated CPU monitors both front and rear shifting for precise and consistent derailleur alignment ● Computer integration allows the front derailleur to track the chain eliminating the need for manual trim and also eliminates chain drop when shifting inward from the big ring. ● 124g http://www.velonews.com/files/images/SM_BT79_side.Thumbnail2.jpgThe lithium-ion battery pack holds a 1000-kilometer chargeSM-BTR1 Dura-Ace Di2 Battery● High performance Lithium Ion composition ● Rechargeable (1.5 hours for full charge) ● Mounting bracket to easily adapt to most bikes ● Approximately 1000 kilometers of heavy use between charges - 7.4V ● 68g SC-7900 Flight Deck Cycle Computer● Gear indicator with virtual cadence ● Heart rate monitor ● Estimated caloric consumption ● Altitude & inclination ● Battery life indicator ● Wireless PC connection Mampara2008-08-01 05:14:12 Link to comment Share on other sites More sharing options...
willy Posted August 1, 2008 Share how many arms and legs will I have to loose to afford it? Link to comment Share on other sites More sharing options...
wisecrack Posted August 1, 2008 Share I like Shimano a very innovative company not like others who rather go the extra gear route Link to comment Share on other sites More sharing options...
fandacious Posted August 1, 2008 Share i'm gonna get these shifters JUST so that i can change someone next to me's gears... especially on those hills... Link to comment Share on other sites More sharing options...
wisecrack Posted August 1, 2008 Share Imagine forgetting to recharge while battling a steep hill Link to comment Share on other sites More sharing options...
WorcesterWheelers Posted August 1, 2008 Share Guess I'll now have to send my mechanics on an electronics course..... Link to comment Share on other sites More sharing options...
madmarc Posted August 1, 2008 Share And i'd luv to see what's gonna happen in the rain Link to comment Share on other sites More sharing options...
SwissVan Posted August 1, 2008 Share All looks and sounds good, BUT I'm not convinced that the reliability issue is equal to or better than what the current cable / spring operated systems offer.Call me negative but I think I'll stay with cables and springs a bit longer. 1. SM-BTR1 Dura-Ace Di2 Battery - Something else that can go wrong and relies to much on human factors influence (i.e. remeber to charge the damn thing).Bicycles are now going to become less enviromentaly friendly... 2. Integrated CPU monitors both front and rear shifting for precise and consistent derailleur alignment Yeah and when the CPU goes PUC (pronounced puke) what then? 3. The front derailleur is the ?brains? of the system.But I prefer to be the brains... 4. Shifting positions mimic Dual Control with the ease of an electric switchElectric switches never fail... dont they not?5. Driven by a servo motor instead of a cable and spring, shifts are identical and precise due to the computer control unit analyzing each shift. Servo motor... computer.... More parts that are unlikely to ever fail while your still at home that is 6. Wiring HarnessWe just got rid (well almost) of wires from bike computers now there's going to be even more of them, imagine if one of these wires gets damaged in a fall or something, there goes your signal to the servo thats going to change the gears on the next uphill. Link to comment Share on other sites More sharing options...
gianni Posted August 1, 2008 Share I'm guessing you all missed Berghardt's problems in the Tour ? His gear got stuck in 53x11 while in the break and he ahd to go over some steep climbs out of the saddle for a while before he could get a new bike...... and he has maechanics to look after himgianni2008-08-01 13:29:28 Link to comment Share on other sites More sharing options...
Dirtbreath Posted August 1, 2008 Share This will be the norm in a few years. Just look at what has happened to cars. Maybe a little solar panel to charge your derailleurs? Link to comment Share on other sites More sharing options...
jabbathemutt007 Posted August 1, 2008 Share I'm guessing you all missed Berghardt's problems in the Tour ? His gear got stuck in 53x11 while in the break and he ahd to go over some steep climbs out of the saddle for a while before he could get a new bike...... and he has maechanics to look after him It was the evil fandacious disguised as Elvis with a Shimano remote. Link to comment Share on other sites More sharing options...
turtlek Posted August 1, 2008 Share Imagine forgetting to recharge while battling a steep hill that is exactly what happened to one of gerolsteiners riders in the tour during the alpe du huez stage!!!!! Link to comment Share on other sites More sharing options...
turtlek Posted August 1, 2008 Share sorry guys i didnt read the whole thread!!!!! Link to comment Share on other sites More sharing options...
Sean Badenhorst Posted August 1, 2008 Share I'm quite happy with mechanical shifting. Can't see how electronic is going to improve my cycling experience that much more. All I see is more things to go wrong. I can't see this becoming the norm and just wish Shimano had rather spent the R&D time and money on developing a more affordable power meter system. Link to comment Share on other sites More sharing options...
Tumbleweed Posted August 1, 2008 Share i'm a klutz when it comes to anything mechanical, even worse when it's electrical. thanks, but no... holy roller2008-08-01 23:31:22 Link to comment Share on other sites More sharing options...
ShortLegs Posted August 4, 2008 Share I'm guessing you all missed Berghardt's problems in the Tour ? His gear got stuck in 53x11 while in the break and he ahd to go over some steep climbs out of the saddle for a while before he could get a new bike...... and he has maechanics to look after him FYI he was on the 7800 mechanical Dura Ace.... Link to comment Share on other sites More sharing options...
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