Shimano Dura Ace Di2 Electronic Groupo

by Ward Bates


From friction downtube shifters to integrated electronic "shifting by wire." It's been a definite progression.


I think it's safe to say that I've ridden almost every shift mechanism in the last 30 years. My first real bike was a Takara with Suntour stem mounted friction shifting. Then, a Trek with Campy friction shifting on the downtube. Then, on to a Dave Scott Centurion Ironman with Shimano's (at the time) radical new Indexed downtube shifters. Whoa! Then I remember getting a Trek with Shimano 600 integrated shift/brake levers when they first hit the market. Whoa, again! Even more radical! "What's so hard about reaching down to shift? Why would would you need to shift in a sprint, anyways?" Looking back, the initial response to integrated shift levers was absurd . . . .


That gets us to the mid-90s where I stuck with Shimano for a while before giving Campy 10sp a shot and found that I really liked it due to the more solid feel and shifting. Although, I still liked being able to "pistol grip" the Shimano lever tops for a my best Euro-Pro impression. Then, it was back to Dura Ace 7800 for a season. Then, to SRAM Red for the last year or so. At this point, I've ridden the Campy 11sp groups, but I think that's the only group that I haven't actually owned.


Somewhere in the middle of all that (mid-90s, I think) was Mavic's attempt at electronic shifting. First it was Zapp, then Mektronic. I clearly remember the shifting being very good, when it worked. There seemed to be a little problem with reliability in the rain that they never really got sorted out. The ergos of the Mektronic levers were a bit odd at the time, but strangely similar to the current Campy 11sp . . . .


So here we are in 2009 and Shimano's new Di2 group is here. My initial thoughts after reading the early announcements were, "Yeah, I remember Mavic's stuff . . . I just don't trust electronics . . . What if I get electrocuted in the rain?" But then I came to my senses and thought, like so many others, "Maybe this is the secret! Maybe these pesky cable actuated systems have been holding me back all these years! With this new stuff, my pro career is a reality!"


At our shop, we have both an Orbea Opal with the Di2 stuff and also my new Pinarello Prince Limited Edition that was designed for the Di2 group. All wires are internally routed and it's just a beautiful implementation. The Orbea is just a stock frame and the Di2 kit for that is probably what most people would end up with unless they bought a Di2 specific bike, like the Prince Di2. The wiring on the Orbea is pretty simple and Shimano provides this neat little tape that works quite well at securing the wires to the downtube and chainstays, without looking bad at all. I think that I'd use some strategically placed SuperGlue and just glue the wire directly to the frame once I was happy with the placement. To each his own, though.


On either bike, the battery pack is discreetly mounted just below the bottle cage on a secure metal "thing," as seen in the photo, and it's probably lighter than most small flip cell phones. Charge time is a true 1.5 hours as Shimano says. Mileage estimates from Shimano are in the 600-1000 mile range depending on how much shifting is done. I'm only on about mile 300, but I'll update this when I actually see the battery low warning light. At that point, it's supposed to have about 150 miles left in it. When it's getting ready to completely die, the front derailleur stops working first and then you have 50 shifts left in the rear derailleur. That's a lot, actually. Unless it goes dead on me midway through next year's Paris-Roubaix or Milan-San Remo, I'll probably make it home okay. If it costs me the win in either of those races, though, I'll be quite pissed.



The Feel:
At first grasp, the Di2's ergonomics are, to me, the best out there. The hoods and levers are quite different from the DA 7900 levers. They seem to be a bit longer on the tops, which provides a bigger flat section. They are definitely smaller in diameter and feel more like the 7800 levers when you hold them. I find it interesting that when given the option, Campy and Shimano both went with a low volume shifter/hood. The new Dura Ace 7900 and SRAM levers are both good, but are definitely larger and I've got to say that I prefer the smaller, even with my large hands. The front of the lever has more of a 7800ish protrusion that allows that "pistol grip" position with more control. The brake lever has a very nice shape that is very easily actuated from the hoods and is right there at your fingertips when you are in the drops. Even a woman with very small hands would be pleased with the reach on these levers while in the drops. The brake calipers on the 7900 set are so good that they can have the closer reach and still have plenty of room for braking lever travel. It's pretty cool.



Coming from SRAM Red most recently, I had very few problems with getting used to Di2's lever/button placement. The single lever action of SRAM Red is very similar to Di2s button setup and the location and "throw" of the levers/buttons is almost the same. I can see where moving from Campy or even Shimano's other groups would require some adjustment, though. Still, I have to say that I had no problems with missing shifts by hitting the wrong button as I've read in some other reviews. My guess is that those reviewers only rode it for a minute or two around the parking lot with the rep standing there sweating and chewing his/her fingers while praying that it didn't get crashed.


On the Road:
So here's the part you really care about -- The shifting on this stuff is absolutely the best there is. This stuff shifts dead-on EVERY SINGLE TIME. It may not be "quicker" in actual time, but it's so precise that it doesn't matter.


The actual motion and thought process to shift is no different than any of the other groupos, so that's really a non-issue. You still feel like you are riding a bike. However, you won't find yourself getting frustrated with missed shift while starting up a climb or not being able to get in your big ring while cresting a hill or not being able to get in your little ring while approaching an intersection. It just doesn't happen. Because there is an actual motor in both the front and rear derailleurs, both are able to detect how much load is on the chain and it adjusts the shift accordingly and it always shifts. You hit the button, you barely hear the motor, and then you are in the gear. Every time.


The shifting in the rear is just elegant and spot on. The shifting up front is downright cool. Not that you'd ever really need to do this, but you can stand up and sprint in the little ring, hit the shift button, and be on your big blade without a hitch. The only thing you'll notice is that it just gets harder to pedal all of a sudden. No grinding at all. When going from big to little blade, the derailleur has more finesse to it and can actually complete the shift under both higher and lower loads than with a cable. And because the motor moves the derailleur instead of just "dropping it" suddenly, there seems to be much less chance to drop a chain on the inside. Again, it doesn't seem to shift faster, but the shifts are so secure every time that I think you will ride faster.


Once of the neatest things that you'll experience with Di2 is the auto-trim of the front derailleur. With only an up and down button, there really isn't any way to trim it. So, the front derailleur actually trims itself while you ride. Little x little or big x big, there is never any rub. The derailleurs know their relative positions and sync themselves up accordingly. How do it know? I don't know, but it does.


Also to note is the "adjustment on the fly" feature of the rear derailleur. Once the mechanical limit screws are set, just like an "old school derailleur," fine adjustment takes place via the levers themselves. It's nothing that can't be done with an old fashioned barrel adjuster on the downtube, but it's much easier and much more accurate. You simply press a button on the tiny control box that hangs on your front brake cable housing (this is also where the battery warning light is and is very easy to see and access) to start the adjustment. A light comes on that indicates you are in adjustment mode and then you simply pedal and tap the shift buttons until the noise goes away. It doesn't seem to matter what gear you do this in, but I better double check the manual at some point. Then, when all is quiet, you press the little control button to get out of adjustment mode and you are done. I swapped wheels and the cassette alignment must have been off just a bit, but it took me literally 3 seconds to adjust the derailleur to that wheel - and this is while I was riding.


Pros:
- Best shifting performance out there.
- Lever ergonomics are great. Very much like the ever so popular Dura Ace 7800 group.
- Unique.


Cons:
- Expensive at roughly $4800 for the entire group (cranks, chain, cassette, and brake calipers included).
- Not the lightest group. Not the heaviest, but for the weight weenies, the extra ounce will hurt.
- Risk of electronic failure. I'm not sure it's any greater than the risk of breaking a cable on an older derailleur, but it's a bit too soon to really say that, though.


I'm tired, so I'm not going to spend any time discussing the cranks and brake calipers since they are the same as the regular 7900 stuff. They are very, very good and there are plenty of reviews out there, so let Google be your friend and go forth.


Ward Bates
Glory Cycles
ward@glorycycles.com


Update:
I've been riding the Di2 stuff for 5 months now and every day, I'm still impressed by it. No adjustments, not a single missed shift. Nothing. The battery is lasting me about 1200 miles in heavy rolling hills (lots of shifting). The stuff simply is incredible and because it makes it so easy to shift perfectly every time, I think you'll actually shift more and be in the correct gear more often.