- The Shimano Dura-Ace Di2 9070 rear derailleur functions like the original.
- The road shifters each have three E-tube sockets, allowing for many extra shifters to be hidden around the bars.
- The grip portion of the shifter has shrunken, making it easier to reach around.
- The up-shift button now extends slightly higher up than the original.
- The E-Tube Junction Box.
- This 5-plug junction box enables a bike built with road shifters to add TT shifters to clip-on aerobars.
- Fewer wires up front thanks to the E-Tube system.
- The front derailleur stay similar to the first Di2 version.
- WIth a single bolt diameter crank option, new Dura-Ace can use compact or standard rings.
- Only four spider arms.
- Outboard battery stays the same, and Shimano has added an inboard battery designed to fit in a seatpost.
- Chain mounts in any direction.
- Yes, it has 11 cogs, creating tighter gaps between gear ratios, but forcing wheel maker to create new freehub bodies.
- Dura-Ace 9000 brake calipers.
Shimano’s new Dura-Ace Di2 9070 electronic group adds simplicity and functionality.
As Shimano puts it, the biggest upgrades to the new Dura-Ace Di2 9070 groupset are at the front of the bike. It still changes gears with incredible precision—not much has changed there—but shifter ergonomics, the wiring assembly and shift programmability, have all been dramatically upgraded.
Dura-Ace Di2 9070 is the beneficiary of a big piece of trickle-up technology. This new kit has the same E-tube wiring system that has been used on Ultegra Di2 for the past year. Not only is this new system marginally lighter than Dura-Ace Di2’s original wiring system, it’s also far more functional.
The heat-shrink waterproofing sheaths that the original required to withstand the elements are gone. E-tube wires plug straight into the shifters, junction box and derailleurs without ancillary protection.
Shifters and derailleurs both connect straight to the Junction Box, the system’s hub that mounts around the stem. Shimano has versions with three and five plugs to allow multiple shifter positions. For example, if you have a kit with road shifters and you want to install TT shifters on a set of clip-on aerobars, Dura-Ace Di2 9070 can do that using the five-position Junction Box. The original can’t.
The tangle of wires needed to build a tri bike with Di2 TT shifters and brake lever shifters will be replaced with a cleaner assembly. Only road kits were on display, so we’ll have to wait to see the final tri version.
Road shifter ergonomics have also been changed, and many people will likely find the new version better than the previous. The diameter of the road shifter is smaller, enabling a more solid grip regardless of hand size. The lever itself can be spaced up to a centimeter closer to the rider than the standard position.
Using a laptop, 9070 shifters can be programed to execute customized multi-shifts with a single press. The rider can set it up to shift non-stop when holding the button, and to jump multiple cogs at a time after briefly holding the shift button instead of clicking through each shift.
Burning through multiple shifts at once forces the chain to skate atop the cogs (easily experienced with traditional paddle tri shifters), forcing the rider to wait until the shift is complete before pedaling again. Shimano intelligently programed 9070 to shift as quickly as possible while still engaging with each cog so the rider doesn’t have to skip a beat in their pedal stroke.
The current battery is sticking around, and Shimano also has a new version, this one designed specifically to fit in a round seatpost. Instead of unplugging from the frame (like the standard battery) to charge, this one stays put in the frame and charges through the E-tube Junction Box. This new battery could help integrate more of the kit inside a triathlon bike.
New-era Dura-Ace offers more gear selection than its predecessor. Instead of creating one crank for compact rings and another for standard gearing, the new Dura-Ace crank fits compact chain rings, standard rings and in-between gear ratios such as 52-36. (For the detail-oriented: BCD looks small, and Shimano calls it “proprietary,” so it probably isn’t 110.) If a cassette swap doesn’t give the full range of gearing options, the rings can be changed to reach even more gears. These next generation components do not offer a rear cassette reaching all the way down to the 32-tooth easiest gear found on SRAM’s WiFli component groups. They do, however, have an 11th gear, to tighten the spaces between gears on the broader cassettes such as 11-28. These new 11-speed cassettes are 1.85mm wider than the 10-speed versions, meaning current freehub bodies need to be changed to fit these components. Pretty much every wheel maker is working to accommodate the change. Shimano’s own 11-speed hubs are capable of mounting 10-speed cassettes with the addition of a spacer.
Finally, the chain is now omnidirectional so a sleepy mechanic can’t put it on backward.
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