Dura-Ace Di2, a Deeper Look

Dura-Ace Di2, a Deeper Look

Some years back I got a chance to ride Dura-Ace Di2 before it was officially unveiled to the press. I was pretty thrilled to get the opportunity to ride a product without the skewing that comes from having read others’ opinions before trying something. I went in with a blank slate and an open mind.

The funny thing is that my takeaway was exactly what everyone else has had to say since then. The shifting is clearly faster and smoother. However, at first, the tactile feel of the buttons is frustrating because there is so little feedback. Without a distinctive click, you’re not really sure you’ve pressed hard enough. Also, at first, it’s easy to confuse the two buttons because they are so small.

But what about when you’ve had a chance to ride the group, really get to know it over a few months? Do the advantages really bear out? And what of those dings? Are they really that big a deal?

I’ve been riding Di2 on a few different bikes over the last few years but more recently have had a number of months on a Felt AR FRD with Dura-Ace Di2 and have come to a few conclusions about Shimano’s top-of-the-line road group.

IMG_0474No matter how hard I have tried, I’ve never executed a front shift as fast as this thing.

The chase
I’m not a fan of conspicuous consumption, rampant consumerism or Jones-keeping. Just because someone else has the new iPhone, I’m not a person compelled to stand in line in a mall. My interest in new bike equipment has always stemmed from the realization that those accrued advances from one generation to the next usually translate to a more seamless experience, making my ride a more transparent integration of rider and road. Frankly, unless the upgrade makes the bike recede further into the background, there isn’t much reason to make the purchase. Once the bike is invisible, that’s when you can hit flow.

If there is one thing Shimano has flawlessly understood, it’s this fundamental truth. The bike is a tool and if you’re thinking about your tool, you’re not focused on the ride.

Di2 takes this notion—that you shouldn’t have to think about your bike—and chases it relentlessly. Of the many drivetrains I’ve used in my life I can say that none come closer to acting like the system software of an Apple computer than Di2. That this is the quietest drivetrain yet devised is well-documented. That’s nice. No one wants to hear your bike, not even you. Then there are those occasional pops and clinks that signal a shift your drivetrain didn’t particularly appreciate. What I’ve yet to hear Di2 produce is one of those too-many-watts-too-few-rpms bangs. Nary a one. That first generation of Red could produce some noises that made me back off and look down at my bike. That’s definitely not in-the-moment.

Because the buttons are set to function in the same way as the levers of STI, the function is really pretty easy to get down. Have I occasionally missed a shift because muscle memory tricked me after riding a Campy-equipped bike? Yep, it’s happened, but that was a fault of my wiring, not its.

IMG_0475I’ve yet to use a rear derailleur that matches this one for flawless function.

The greatest differences only begin to emerge after riding the group steadily. The first, biggest is that I shift more frequently. It’s the same increase in shifting that I experienced when I switched from down tube shifters to integrated control levers. I probably shift 50 percent more with Di2. I’ve also noticed that I no longer worry about when to shift, though admittedly that was a relatively minor worry, one that crept up only during steep climbs. With Di2, I’ll shift in moments where I might otherwise skip shifting because I was fearful that I’d tax the drivetrain into a missed shift or some awful bang as the chain climbs over that critical tooth.

With today’s wide-ranging 11-speed cassettes and compact cranks, front derailleurs have the toughest job they’ve ever had. I’ve had trouble getting Dura-Ace 9000 mechanical to align perfectly up front. As a matter of fact, I’ve approached perfection, but I’ve yet to hit true flawlessness, but that’s at least better than I’ve been able to achieve with SRAM’s yaw derailleurs. One of my favorite features of Di2 is the autotrim that the front derailleur performs as you push the chain around the cassette. You want ideal shifting in front as well as back? Di2.

IMG_0481The climbing shifter is super helpful and I like the exposed junction box so I can trim shifting if necessary.

Put your finger there
One of the cooler features of Di2 that almost never gets discussed or even mentioned are the satellite shifters. Shimano makes these, but no one specs them with the bike and consumers are so accustomed to not upgrading their groups in any way that very few riders get the sprint or climbing shifters added to their bikes.

It’s a shame because they absolutely rock.

They require some learning. I’d suggest it’s akin to using paddle shifters on a car that will otherwise shift automatically. You have to remember those little buggers are there. I’m most apt to forget about them if I’ve been riding other bikes (like my Bishop). But after riding the Felt for a few days, my thumb will instinctively reach for the little button on the back of the bar top. It’s a terrific feature for when a climb steepens gradually. Cooler still is when a climb begins to roll off and you’re able to upshift as you near the top of the saddle. Riders behind don’t see your hand go to the lever, and yet you accelerate. I don’t ride many people off my wheel these days, but I gapped a buddy by upshifting a few times as a hill flattened. Telling the two buttons apart is as easy as with the lever. The smaller, closer button executes downshifts. The bigger button that’s a bit further away does upshifts.

Of course, because this is Di2, you can program the buttons to do whatever you want. Why anyone would want to, say, make the left buttons execute upshifts for front and rear and the right buttons tackle downshifts for front and rear, I can’t fathom. Other than to deliberately be obtuse, I can’t see the point of going to all that trouble. I just don’t have that much time to devote to changing a working system.

In short, reprogramming the Di2 buttons is the Dvorak keyboard of the bike world. Don’t do it unless you trade on weird.

IMG_9634The auxiliary sprint shifter is one of those things that makes you wonder how you ever lived without it.

The other auxiliary shifter are the sprint buttons. It is but one button per side, and unless you reprogram it, it executes upshifts on the right and downshifts on the left. The sprint shifter requires a light touch—I’ve overshifted a number of times, but I think I finally have the quick and gentle squeeze down. It’s a handy thing for descending as well as sprinting or, frankly, any time your nose is in the wind and you decide it’s time everyone suffered.

IMG_0476Dura-Ace brakes have varied maddeningly between great and mediocre. This generation is superb. 

That hole in your pocket
Shimano long maintained a noticeable performance difference between Dura-Ace and Ultegra. When I think back on the eight, nine and 10-speed mechanical groups, Dura-Ace always had faster shifts, better tactile feedback, more powerful braking and less pull from gravity. As a result, it rather understandably commanded a premium at retail. (Hell, it commanded a premium at shop cost).

All of that was true until Di2. With the current Ultegra and Dura-Ace 11-speed groups, I can’t tell them apart when I’m riding a bike. I’ve weighed the stuff, and the Ultegra is heavier, but the shifts are just as quick and crisp, at least so far as I’m able to perceive and if there’s a real performance difference between the brakes of the two groups, it evades my powers of detection, which is remarkable because braking was the ace-in-the-hole for anyone wondering why you dropped the extra cash. No matter what anyone might say about the light touch of the shifting, the fantastic ergonomics of the lever, or anything else, you could always respond, “Yeah, but I like to choose when I stop.”

Discussion over.

IMG_0477Di2 levers accommodate hands both large and small; the adjustable lever throw is helpful for ideal fit.


Except, not any more. I can’t come up with a reason for anyone to choose Dura-Ace over Ultegra, other than weight. I suspect nine times out of ten the deciding factor in a purchase will be some other factor in a bike—such as frame quality—but when you consider the extra silver you’ll toss just to get Shimano’s best parts, the better frame on which they are likely to be spec’d is a better excuse. If I were buying a group to put on a frame, Ultegra Di2 would be near the top of my list.

I’ve ridden a few Di2 bikes that were equipped with non-Shimano cranks. In each instance I was dismayed by the aforementioned problems with front shifting. Here’s what I didn’t sufficiently appreciate until I put three different aftermarket cranks on the same bike: No one’s cranks and chainrings run as true as Shimano’s. Bear in mind, this isn’t a comparison to Campagnolo or SRAM, but when considered against other widely available cranks (some of which get OE spec), their chainrings simply don’t run as true and as a result, front derailleur performance suffers.

Another feature I really love about Di2 is the ability to adjust the shifting on the fly. Push the button on the junction box, and hold it for two seconds and then use the shifters to execute micro adjustments. I had to do that this past winter at the Old Caz Grasshopper. I was on a brand-new Diverge and while it was 98-percent right, there was a bit of trouble with the front shifting. I was able to sort that out on a flat, straight stretch of road, by myself.


It’s fitting that I’m a writer; I’ve got rather fine bones. I’d not have gotten far as a boxer. The ergonomics of the levers from Campagnolo, SRAM and Shimano are so much better than they were 15 years ago, I’m amazed that I tolerated what was out there. As good as the 9000 mechanical and various other lever shapes are, I have to admit that my hands are happiest on the Di2 levers.

It’s this little detail, that people with smaller hands will find improved comfort on Di2 levers, that makes me think that the easier shifting and smaller hoods make Di2 a better choice for most women.

The straight poop
Dura-Ace continues to be the best of the best (though there’s stuff on the horizon that may challenge it soon). There is, however, the economic reality that most of us live and work in. When I consider how much more affordable Ultegra is, and how close in performance it is to Dura-Ace, I can’t in good conscience tell anyone to splurge, that it’s worth it. Ultegra is better than it ought to be.

That said, in a world of 700-gram frames, people will always want a lighter bike, and Dura-Ace does deliver that. Shimano just needs to do more to differentiate Dura-Ace from Ultegra.

I adore this group. If I were pulling down mid-six figures, I’d put Dura-Ace Di2 on every bike I owned. I’d buy extra bikes just to put it on them. I’d have a mixed-surface bike with their hydraulic brakes. There’s no question in my head that a faster shift is better, that a more powerful shift lends confidence, but flawless shifting makes for a transparent bike. That’s the thing about Dura-Ace, the highest compliment I can give any group—that there are times I forget I’m using it.

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  1. Kyle V.

    I believe that the satellite shifters only work with Dura-Ace. So the reasons for buying Dura-Ace over Ultegra would be the satellite shifters and weight. (I bought Ultegra)

    1. AC

      Pretty sure they work with either group, but require a junction box with enough ports to accommodate the extra cable. There’s a 3 and a 5 port option IIRC.

  2. Chris

    The programability of the shifters does more than cater to the obtuse. Reprogramming a given shifter to execute only downshifts, and the other to execute only upshifts is a fantastic edge for applications such as cyclocross. Numb hands make the aforementioned small buttons damn near impossible to accurately hit, but pawing at one shifter or the other works just fine. As long as you hit something, you’ve got shifting. Braking with frozen hands is another issue altogether…

  3. Les.B.

    The one problem I’ve had with shifting Di2 is that sometimes if front and rear buttons are pushed simultaneously, the chain will pop off the chain ring. Maybe one is not supposed to hit both buttons simultaneously, I don’t know. But now I wait a few hundred milliseconds between front and rear shifts.

    I got DA because at the time Ultegra was not available in 11-speed. Later I decided that because of arthritis in a knee, that I needed a 32 granny in the cassette. DA has no such, but Ultegra does. So the wrench at Bike Effect put a Ultegra rear derailleur in the back, to work with the DA derailleur in front. No problemo, they play together just fine.

    1. BJM

      I’ve had Di2 since its inception, and how have it on 3 bikes. One of the reasons that I love it is precisely the ability to press both buttons at once. If the chain falls off when you do that, then an adjustment is required. I use the two button shift frequently including in races, under load, while climbing. It has never ever failed me.

  4. tnc

    Ultegra Di2 11speed (6870 series) allows both remote sprint shifter (dedicated port) and climber shifter (standard e-tube port). See page 17 of the dealer’s manual (DM-UL001-00-ENG.pdf)

  5. Josh Z

    Your experience with Di2 generally mirrors mine. No one needs it until you have it and get used to it. In fact, I can’t see getting a bike with discs until I’m ready to punk down the money on a disc/Di2 bike.

  6. Scott G.

    Les B., Di2 would finally make an easy to shift triple, where is auto front trim
    more important than on a short stayed, Shimano triple ?

    Mr. P, the chain rings shift wonderful, but I’d like a 46/30 or 48/32,
    11t cogs mean smaller big rings. a 13-30 cassette would be nice slow guy option.

  7. Author

    All: Thanks for your comments; keep ’em coming.

    Shimano tells me that the auxiliary shifters only work with Dura-Ace, dealer book notwithstanding. So yes, that’s a reason to focus on Dura-Ace over Ultegra.

    Scott G: Back in the ’90s Shimano offered a group on entry-level road bikes. It featured a 13-26 cassette and a 46/36/26 triple. One of the most intelligent groups I’ve ever seen, given the actual fitness of most riders. Why such gearing went away, I can’t tell. A 53×11 is monstrous gear that most people will never be able to turn over at 110 rpm. I’m all for drivetrains that start lower and end lower.

    1. tnc

      Hi Padraig,
      I’m surprised about this statement from Shimano. Actually, I’m using now auxiliary sprinter shifters on my Ultegra Di2 (6800). To be fully honest, I’m not using the Shimano sprint shifters but a custom made version I did using standard etube connectors and some tactile switches. The connector is plugged in to the 3rd port (sprinter shifter dedicated port).
      Anyway…if Shimano say so… Roma locuta, causa finita 🙂

      Thanks for the post

  8. Chris

    Another feature of Dura Ace (and definitely not available on Ultegra) that is hardly ever discussed is the hidden button atop each shifter under the hood. With the Shimano D-Fly Ant+ attachment, you can use these buttons to control a Garmin head unit, including start/stop, lap, and changing pages. Very minor until you get used to it and suddenly have to go back to moving your hands to control it….kind of like getting used to the satellite shifters. With the new Edge 520, which abandons the touchscreen, this will be even more useful. I also have my Garmin display the rear cog being used, to avoid cross-chaining. When training, this is not that useful because you can hear the crosschain or steal a glance downwards, but while racing, you don’t want to look at your rear cassette, and the only thing you might be hearing is your heart about to explode.

  9. Patrick

    I combined the better looks and slight weight advantage of Dura-ace cranks and brakes with the more affordable Ultegra Di2 (6870) shifting package for a best of both worlds scenario. And yes, the satellite sprint shifters work perfectly with Ultegra Di2. I use and absolutely love them.

  10. Gian Marco Mazzocchi

    Excellent review Padraig. My point of view after using Di2 on my tri bike for one year is the same.
    I was wondering if you’ve ever tried the Praxis LevaTime chainrings with Di2 and what’s your opinion about them.
    I’ve been using them, together with the InfoCrank power meter cranks, and I’m pretty happy about their performance.

  11. Author

    I’m going to have to talk to Shimano about that discrepancy between what they report with the shifters and what the real world allows. It’s not like Shimano to be wrong about their own stuff. That said, it’s one less reason to spend the bucks on Dura-Ace.

    Gian: No, I haven’t tried the Praxis rings with any Shimano products. It’s been a while since I got worked up about chainrings, but the Leva Time are the first to do it in ages. I’d definitely like to give them a try.

  12. Nick

    I recently demoed a Di2 equipped bike. While I did enjoy the smaller hood ergonomics you mentioned and the powerful front shift, overall I felt that the electronic nature of Di2, in its current form, intrudes upon the flow experience of riding. I missed the subtle increases or decreases in shift effort/ cable tension that let me know roughly where I am along the cassette. I also found the whine of the Di2 derailleur motors annoyingly intrusive and very unpleasant compared to the refined “snick” of most analog drivetrains these days. As I ascended a particularly long gravel climb here in Colorado, my consideration of the quiet beauty nearby was interrupted yet again by the harsh electronic whine of another Di2 shift. As much as motorized derailleurs have improved shifting technology (I appreciate how analog Dura-Ace and Ultegra have improved front derailleur designs as a direct result) I prefer to keep my cycling experience non-electronic. It’s like the book vs. tablet debate: the content is the same but the experiences are very different. I’m not sure I need more electronics in my life.

    1. Craig P

      The battery has lasted so long ( for me anyway ) that as long as you check your battery every couple of weeks, you shouldn’t run out of juice. But if you are worried, get a Shimano Di2 D-Fly Wireless Transmitter Unit – it will show your battery level on your Garmin !

  13. Charlie

    Electronic or Mechanical? Depends.
    Nick, your post motivated me to share some thoughts on this.
    I’ve been riding Di2 11speed for the past year. Prior to that, I had ridden mechanical, all the way back to down-tube shifters in the 1970s. Why did I buy Electronic? Because my mechanical group was worn down to the point where I could barely sell it to raise a few bucks for a new group. I didn’t have my eye on Electronic, but when I shopped for a new group, it seemed that a high-end$ mechanical group will be difficult to sell in four years when I’m done with it. The high end market is becoming electronic at a pretty good pace.

    A test ride and some homework was all it took for me to plunge into electronic. One thing is for sure: I won’t go back to mechanical. Recently, I’ve ridden my back-up bike (mechanical 11speed) and although it works great, actually better in a couple of ways, it does not give me the seamless riding experience of electronic. Other than Di2 satellite shifters (for which I would gladly pay $1k alone!), there is no single great thing electronic does that makes it better. Rather, it is the sum of many smaller things and the benefits they provide while working as a complete system. Basically, operating the bike happens with less distractions and allows me to concentrate more and take advantage of a much less interrupted, therefore more enhanced, tempo. Less interruptions in tempo make for a smoother, less fatiguing ride. “Tempo” doesn’t mean only cadence in this context. I’m talking about the tempo of your effort and the uninterrupted tempo of getting in and out of the saddle smoothly, etc. Building the satisfaction and confidence that you are in charge of your output for the road ahead.

    Following is a chart of these thoughts. I hope the formatting stayed in tact. In the end, here’s how I feel about buying electronic (but don’t buy Campy– the market leader in mediocre ownership experience): If your mechanical group is worn out, replace it with electronic. If you are really into your bike(s) and don’t mind spending, buy electronic. If your mechanical group is in good shape and you are happy with it (and you aren’t into your bike) then don’t spend the bucks for electronic. If you’re not into your bike, I think you would be disappointed for spending $1500 (minimum). You’d probably feel the electronic is nice, but you’d also feel that your mechanical system worked just fine. Note: Tri bikes are an exception. They can benefit greatly from the multi shifter location options w/ Di2. I also feel electronic is much more useful to someone who rides in rolling terrain and long climbs versus someone who rides in the flatlands. I grew up riding flat terrain, but have been in the Santa Cruz mountains for many years now. In the mountains it seems as if I shift 50 to 100x versus on the flatlands. Electronic is fantastic if you are shifting a lot.

    *Climbing shifters (particularly on rolling terrain) R Maintain smoother tempo
    *Requires less effort shift F/R Maintain smoother tempo
    *No long cock-your-wrist paddle swings (mostly Campy) F/R Fewer sloppy shifts maintains
    smoother tempo
    *Very consistent shifts F/R Maintain smoother tempo
    *Great out of saddle shifting F/R Maintain smoother tempo
    *Down shifts before entering tight turns F/R Safely select best gear for corner exit
    *Auto trim front der F Maintain concentration
    *Micro centering rear derailleur R Optimize shift quality, reduce noise
    *No cable tension maintenance F/R Concentration
    *No shifting problems from slowly developed cable fray F/R Concentration & no maintenance cost
    *No cable dirt, corrosion F/R Concentration & no maintenance, cost
    *Sleeker installation all Aesthetics (weenie)
    *Resale (Demand for electronic is increasing) all Slight offset to upcharge for electronic

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