Shimano Dura-Ace Di2 9070 Review

The time of electronic shifting has finally come of age.  It offers precision shifting in all conditions, a self-trimming front derailleur, push button convenience, and low maintenance.  I was originally weary with the first generation of Dura-Ace electronic shifting, however, the Di2 9070 is definitely cream of the crop.

The Di2 9070 Groupset

Here are several key features on the new Dura-Ace 9070 Di2:

1.  There are multiple shifting options available – “climbing”, “sprint”, bar-end, and standard brake lever.  The new junction box (SM-EW-90 A/B) enables the rider to connect any of these shifting options neatly below the stem and the box can be mounted anywhere you would like.

2. The PC linkage device allows you to plug your bike into a desktop computer (talk about Back to the Future! Will I warp in time when I hit 1.21 gigawatts? ) to program the functionality of each shifter and update the firmware of each component.  For example: You can now program the shifters to “multi shift” (which allows the bike to continuously shift as long as you continue to hold the shift lever).  The PC link also allows the use of advanced software to diagnose and troubleshoot any problems.

3. The shifter lever has been re-designed and offers a comfortable feel.

4. The battery is completely internal and rests directly inside your seat post.  You can remove the battery for charging or use an external plug located at the junction box.

5. With the external battery, the entire system weighs only 60 grams more than the Dura-Ace 9000 mechanical group set.

6. The Etube wire can be purchased in various lengths to allow for a precise cable run.

7. It is 11-speed and can be configured with up to a 28t cassette.

E-tube Project Software for programming, troubleshooting, and customization

Real World Testing:

I took my Cevelo R5 VWD equipped with the new Shimano 9070 Di2 towards route 9W and into Rockland, NY for the GFNY13 training ride.  The ride consists of approximately 100+ miles and 6,000+ feet of climbing, and not to be forgotten, some 15mph wind gusts that certainly added to the challenge.

Having used the Shimano Dura-Ace 9000 mechanical group for the last four months, I can happily say switching to the Di2 9070 was pure joy.  The transition felt seamless.  Push button shifting was intuitive, effortless, precise, and as stated earlier, the feel of the levers were extremely comfortable.  You literally only need  slight touch to shift the front or rear derailleur.  This gave me much better control while on the hoods and while standing up for climbs or a brief sprint.

Ergonomic Lever

Extra E-Tube port

I programmed my rear derailleur to multi-shift while holding down the lever.  Shifting was uninhibited, predictable, and smooth.  It reminded me of an automatic transmission in your car.  The fast reflexes of  the system led me to believe that drivetrain shock under pressure was almost nonexistant.  Standing up to sprint and shifting without easing up made my bike feel almost flawless.

Rear Derailleur Installed

The front derailleur adjusts trim on the fly for ultra quiet operation, while allowing for fast and powerful shifting.  Having had my bike properly adjusted by a trained Di2 mechanic definitely helped, however, I felt absolutely no chain rub whatsoever during my ride.  The only sound I would hear during my ride was the servo working like a good little robot.  I remember being annoyed by manually adjusting the trim on my mechanical group in the past and was excited to not worry in the future.  The only problem I encountered was shifting from the small ring to the big ring in which the derailleur failed to engage once or twice.  But, nevertheless, perhaps I was pedaling a bit too hard during the shift.

Front Derailleur Installed and Battery Mounted

Shimano manufactured two different types of batteries for the Di2 system.  One can be internally mounted within your seat post or frame (if your bike allows it).  The other, which I purchased, is an external battery that can be installed anywhere around the bottom bracket or using your water bottle mount.  Shimano claims that you can reach approximately 1,500 miles before recharge and charging time is only a little over an hour with the external charger.

Overall, making the switch to the Shimano Dura-Ace 9070 Di2 is completely worth it despite the expense and negligible added weight of the battery compared to the mechanical group.  The ultra fast, precise, reliable shifting is second to none.  The system truly gets out of the way and lets you do what you need to do – RIDE.

SMJC 40 Junction Box Installed with Precision