2012 Shimano Ultegra Di2 electronic road bike group drivetrain ride review and tech details

Shimano invited us to the UCI headquarters in Aigle, Switzerland, to test ride the new Ultegra Di2 electronic shifting group. As expected, it worked amazingly well and, at half the price of it’s Dura-Ace brother, is set to change the landscape of bicycle drivetrains.

First, a primer. From start to finish, Shimano spent five years developing the Dura-Ace Di2 system. Three years of design followed by two years of real world testing under their sponsored pros. Why so long? Because as we all know, whenever such a high profile product is released, it needs to be perfect from day one lest it get panned by the press and have a massive uphill battle in the marketplace. At the risk of sounding like a Shimano fanboy, it pretty much was perfect.

Like all things electronic, though, technology changes, lessons are learned, Moore’s Law happens and things improve. The result is the new Ultegra Di2 group – a system that is better in many respects, performs just as well and cuts the cost in half. What that means for us is complete bikes on the showroom floor this fall with an electronic drivetrain in the $4,300 range. And you’re going to want one.

Get the full scoop, ride review, pics and video after the break…


Price and weight. Technically performance, but unless you’ve been on Dura-Ace Di2 for a while, you’d be hard pressed to find any less performance coming from the Ultegra group. Here are the numbers:

Component Weights by Group (in grams)
Dura-Ace Di2 Ultegra Di2 Dura-Ace Mech Ultegra Mech
Rear Der. 225 270 166 189
Front Der. 124 165 67 89
Levers 255 313 379 447
Brakes 293 317 293 317
Cranks 735 790 735 790
Cassette 163 209 163 209
Chain 252 267 252 267
Other 172 151 94 94
TOTAL 2219 2482 2149 2402

*FD is braze-on. Cranks are 53/39 with BB. 11-23 cassette. 114 links in chain. All weights provided by Shimano. “Other” includes the wiring, battery & mount, junction box and control box for the electronic groups and shift cable & housing for the mechanical groups.

As for price, the Ultegra Di2 electronics parts ring up at $1,600 USD (individual component prices in this post). Compare that to $2,700 for the Dura-Ace Di2 bits. If you’re comparing the entire group with cranksets, bottom brackets, brakes and cassette, Ultegra is about half, coming in at about the same price you could be an entire Dura-Ace mechanical group for.

2012 Shimano Ultegra Di2 electronic road bike group drivetrain ride review and tech details 2012 Shimano Ultegra Di2 electronic road bike group drivetrain ride review and tech details

Cosmetically, the Ultegra housing is slightly larger where the servo motors are housed. This is because they use larger, less expensive servos than DA. In both derailleurs, the servo rotates lever arms (the silver and black ones on the top of the rear derailleur shown at left, above) that form part of the parallelogram. This is very different from the prototype Campagnolo electronic derailleur we’ve seen.

2012 Shimano Ultegra Di2 electronic road bike group drivetrain ride review and tech details

The brake levers are alloy rather than carbon.

2012 Shimano Ultegra Di2 electronic road bike group drivetrain ride review and tech details

The battery indicator/control box is slimmer and has better inline cable routing. To check the battery’s charge level, simply press and hold any shift button.

2012 Shimano Ultegra Di2 electronic road bike group drivetrain ride review and tech details

The Ultegra Di2 wires are much thinner, and the “zip ties” snap on and off unlike the fixed ones on DA’s wire. Because they’re easily removable, custom frame builders will have a slightly easier time doing trick installs. For normal installations, the ties keep the wire pressed against the inside of the bike’s tubes to keep it from rattling about. The tool (top left) is used to safely push the wires into the ports on the junction box (rectangular thing), levers, battery and control box. The other end pulls them out. It’s designed to put the pressure on the plug rather than having you yank on the wire and possibly mess things up. After all, they’re about $30. Each.

There are two cable kits, one for internal wiring and one for external. The internal setup gets the small rectangular junction box. The external uses a junction box that mounts under the BB shell and has all wire plugs on one side.

2012 Shimano Ultegra Di2 electronic road bike group drivetrain ride review and tech details

Dura-Ace wires use a five-pin connector (left) that has specific mount points within the wiring schematic. The Ultregra Di2 wires are 2-core wires based on CANbus technology that allows networked devices using multiple controllers to communicate with each other. This lets frame manufactures make the holes smaller and the wires are lighter. Perhaps the biggest benefit of the new design is that it’s waterproof once it’s connected; it doesn’t need the heat shrink seals that the Dura-Ace version required. That means it’s more easily moved to a new bike in the future.

2012 Shimano Ultegra Di2 electronic road bike group drivetrain ride review and tech details

Another killer new feature is their diagnostic device. Dura-Ace has one, too, but it requires you to plug each component in separately and simply blinks lights to indicate a problem. This new one has a very, very nice GUI that loads on your PC (Mac version should be coming soon!) and only requires you to plug it into one shift lever to read the entire system:

shimano ultegra di2 computer diagnostic and tuning program graphical user interface for pc and mac

If everything turns green, you’re good to go. If a part shows as red, you’ve found the problem. If everything looks green but it’s not working properly, chances are good that it’s a bad/damaged wire somewhere. Unfortunately, the only way to test that is either swap in a new part (hopefully your Local Bike Shop will stock them) or swap wires between components and see if the red part changes.

The software and device is only intended to locate the damaged part, not diagnose what’s wrong with it. However…

…it does let you customize the way the shifters work. You can pick which button shifts up and down or even swap it so the left shifter/lever controls the rear derailleur. This is a great feature because the system comes set up to operate similarly to the mechanical versions in that the inside lever on the right moves to harder gear on the cassette but moves the front derailleur down to the small ring. I found myself getting them mixed up, and being able to make the same button on both sides control up shifts or down shifts is pretty cool.

shimano ultegra di2 computer diagnostic and tuning program graphical user interface for pc and mac

Alas, the unit is really intended as a shop tool, and at $200 to $300 expected retail, it’s probably not something most cyclists will have laying around. If you’re loaded, though, it can make for some pretty cool bike geek party tricks. With it plugged into your system, you can tune the shifting and have it simultaneously show you where the derailleur is on screen and move the derailleur on the bike. It borders on creepy making something move just by tapping a button on your computer, but it’s pretty darn cool.

Speaking of adjustments, Ultegra has 30 steps for each gear (versus 24 for Dura-Ace Di2). You don’t need this tool to setup/tune your shifting, it can be done from the bike, too: Simply press and hold the button on the control module until it stays red, then press the shifter to make micro adjustments on one cog. Once you’ve got it lined up perfectly for one cog, it should be adjusted properly for all gears.


2012 Shimano Ultegra Di2 electronic road bike group drivetrain ride review and tech details

The brains of the operation are in the front derailleur. That, along with having a quite powerful servo, explains the bulky top section. This means that in order to run Di2, you need a front derailleur in the system. Shimano’s Tech Rep Tommy Magrath says the development on this was well before people started getting into 1×10 drivetrains, and really that’s only starting to get popular (as in other than DH) in mountain bikes now. So, for the foreseeable future, you won’t be able to run a 1×10 Di2 setup unless you’ve a) hacked it or b) have a very expensive front derailleur acting as a chainguide.

2012 Shimano Ultegra Di2 electronic road bike group drivetrain ride review and tech details

The battery meter shows the charge level when you hold either shift button. Solid green is 100%, blinking green is 50%, solid red is 25% and blinking red means 0%. However, even when it’s blinking red, you’ve still got an estimated 250km of riding before it’s totally dead. It’ll show as being low earlier when holding the front shifter versus the rear because the front derailleur uses more power. So, if you do drain the battery on a ride, the front derailleur will stop working first, but you’ll have about 180 shifts left in the rear. This is a nice safety net to help get you home.

Actual distance per charge will vary based on how often you shift. Basically, you can expect 1,000 to 1,500 shifts per charge in normal conditions. Really cold weather will work through the battery quicker. Shimano says it’s been tested from -32ºF to 120ºF and it works as designed. Honestly, if you can remember to charge your cell phone or GPS cycling computer, you should be able to remember to charge this. Charging time is claimed at just 90 minutes with a guaranteed 500 recharges per battery. You can charge it for any length of time, and supposing you do forget, Magrath says just put it on the charger while you fill your bottles and get dressed and you’ll have plenty of charge for a ride.

2012 Shimano Ultegra Di2 electronic road bike group drivetrain ride review and tech details

Devin Walton, Shimano’s PR manager for the States, says there’s actually less that can go wrong with Di2 than mechanical drivetrains. He said one customer had put more than 35,000 miles on a Dura-Ace Di2 bike before the rear derailleur had to be replaced. That said, there are a couple of minor things to consider before making the leap:

The rear derailleur will work with a 28T max cassette cog. Front derailleur is designed for 50-53 tooth range on the big ring. Those aren’t physical limits, just recommendations for maximum performance.

For cyclocross, it’ll work and it’s covered under warranty. In fact, all of Shimano’s tech and marketing folks at the ride event said it’s pretty much ideal for ‘cross. The only issue is that the front derailleur’s is designed around a normal big ring, so running a 46-ish chainring on the front may only give 99% of the performance. In other words (Shimano’s words, to be exact), the only people that are going to notice a degradation in real performance are the engineers that developed the system. The issue is the cage shape, not the mechanical/electrical bits. Conveniently, their new CX70 cyclocross parts will match up both color and style with these new parts.

As for mud and water, the system is (for all practical purposes) waterproof. In fact, Shimano says they’ve completely submerged the Di2 system at 10m (~33 feet) and it still worked. Real world application: Riding in the rain won’t hurt it. Putting your bike on a roof rack and driving in the rain at 80mph won’t hurt it, either.

2012 Shimano Ultegra Di2 electronic road bike group drivetrain ride review and tech details

See that? That’s a taste of things to come. You may have noticed in those computer diagnostic screenshots there’s the outline of a remote shifter pod. Well, the pic above shows the two wire ports on the shifters to accommodate those and any other future accessories. The second port also happens to be where you plug the diagnostic tool into the system. Shimano said they’re working on both remote shifters and TT/Triathlon bar end shifters for the Ultegra Di2 group, and that other things like the sprinter’s shift buttons are likely in the future. At the earliest, you might see some of these items in the spring. Because of the different wiring plugs, DA bits won’t work with Ultegra.


2012 Shimano Ultegra Di2 electronic road bike group drivetrain ride review and tech details

Shimano would like you to know that Di2 is not about having an electronic drivetrain. It’s about flawless shifting. They proved that with the Dura-Ace version and the Ultegra edition works just as well.

One of the most heralded features of Dura-Ace Di2 is the front shifting, and Ultegra Di2 is no less fantastic.

Stand up to mash gears up a climb and you can shift back and forth between big and little rings effortlessly and perfectly. Not only is it quick, but the auto trim feature keeps it in line with whatever cog you’re in so there’s never chain rub.

If you’ve ridden DA Di2, Ultegra Di2’s rear shifting may seem infinitesimally slower, but it’s still at least as fast as is normally done with a traditional mechanical system. One common complaint about the system is that you can’t dump a bunch of gears before a climb or instantly add a couple for a surprise sprint. Technically that’s true, but the system will basically shift as fast as you can tap the button (see video). So, it’s more about relearning how to dump gears (ta-ta-ta-tap) as opposed to not being able to do it. And it feels much more controlled.

Here’s where I’m struggling: I feel like I should write more. What you really need to know is that it shifts perfectly. Everytime, all the time. There are no cables to stretch, it won’t shift funny on really hot or cold days, and it can’t get mucked up by lack of maintenance or lousy weather.

What’s really exciting about the Ultegra Di2 is that it brings that electronic, flawless shifting to the mainstream. Complete bikes with Di2 are now going to be available at price points that most enthusiast riders (like you!) will consider. And, as you’re considering those bikes – or simply upgrading your existing frame – you’ll likely test ride a Di2 bike. One or two of your friends will show up at a group ride with Di2 and rave about it. Then, if I were a betting man, I’d say an electronic drivetrain ends up on your wish list. If you think I’m just tooting Shimano’s horn, you owe it to yourself to go test ride it. Seriously. As one cyclist to another, and I honestly don’t care if you buy it or not, you’ve gotta try it. You probably won’t want to go back to mechanical shifting.


Shimano was very careful to note that the cables and plugs (everything, actually) were pre-production and not fully watertight on our test bikes. We were warned that they shouldn’t get too wet, but on one of our rides, the ground was damp with puddles in spots from an overnight rain and overcast morning. My bike stopped shifting about 90 minutes into the ride. After about 30-40 more minutes, shifting function returned sporadically and after the full 2.5 – 3 hour ride, it was mostly shifting again. Some of the Shimano guys thought perhaps a little water had entered one or more of the plugs, others thought it might be something else. Unfortunately, we didn’t have the diagnostic tools on hand to test it and find the real issue. Should this concern you? Probably not. The production versions will have better seals at the cable snaps and junctions. Do I still want it on my bike? Yes. Would I still buy it? Yes. Will I tell my friends it’s the second coming of the great Spaghetti Monster? Perhaps after drinking the bottles of wine I borrowed from the UCI’s wine cellar.

If Shimano had everything to prove with Dura-Ace Di2’s launch a few years ago, the stakes are even higher with Ultegra. It’s going to be spec’d on way more bikes and sold to way more customers after market. If Dura-Ace Di2 was seen as an aspirational product of the pros and country club set, Ultegra Di2 will bring electronic drivetrains to the farmers market rides.

We’re on the list for a full, production groupset and will be testing it on both road and cyclocross bikes this fall/winter. Look for a proper long term test early next year – you know, about the time you’ll start looking at all the shiny new bikes with Di2…


In case it’s not obvious, there are three more things that should get you excited:

1. Ultegra’s improvements in wiring, battery management and diagnostics tools will undoubtedly trickle up to Dura-Ace. Probably sooner rather than later, meaning that system will get lighter and better.

2. Potentially, that could actually lower the cost of Dura-Ace Di2. The mechanical DA system is getting a pretty hefty price drop for 2012.

3. K-Edge is already thinking up mountain bike kits for this, too, which should put it into the range of normal rich, not just the super rich.

4. Because it uses the same battery as the DA version, all of those custom battery hacks (here, here and here) will work just fine.


  1. Uri on

    Where are people getting this idea that Di2 enables a DS/Coach/Phantom to shift their bike remotely?

    You pedal, you hit a button, and the chain is moved to a different ring/cog. It’s the stuff in the middle that’s different. If someone is so vehemently opposed to easier shifting, they should probably go back to friction.

  2. moz on

    Carbon frames (some of them are even tested in an air tunnel: i.e pinarello dogma), carbon components, carbon wheels, tubeless tires & last but not least e-shifting. All this package at the price of an I.4lt car.
    I love revolution! So, next time the Tour of France will start from an F1 grid.

  3. MarvinK on

    It’s hard to believe Ultegra is so much heavier than SRAM Force and Rival… and electronic is heavier than Apex. I like the idea of the automatic trim–but I’m not sold. At Interbike in 2009 I saw the Shimano tech fix a dropped Di2 chain more than once at their booth… and Andy Schleck seems to still have problems shifting up front (TdS) with the electronic stuff.

  4. Justin on

    After the fiasco that is current generation Dura-Ace, Ultegra, and 105 mechanical shift levers, I am pretty stoked to see these on the market. No more worrying about inevitable cable friction and degrading shift performance that requires cables and housing to be removed and replaced every few months. My job as a mechanic should get a little easier. Thank you Shimano.

  5. Jeff M on

    Really your passing judgment on something you saw at a trade show back in 2009 to something that is being released in 2011.

  6. MarvinK on

    @Jeff M: Tour de Suisse was this year… and the price=Dura Ace and weight=Apex are just basic facts. Sorry, not sold on Di2.

  7. Robin on

    Given the next-to-non-existent performance “disadvantage” of Ultegra Di2 compared to Force or Rival, such comparisons are pretty as valid as saying “the meat in watermelon is much more red than white rice.” Further, I don’t remember Shimano making any claims about how uber light weight their electronic groups were. Also, given that these Shimano electronic groups are relatively new to the market using new technology to bicycling (pretty different to Mavic’s two efforts), it’s logical to assume that the weights will come down. Their “excessive” weights are driven by the solenoids and the larger derailleurs required to support them and by batteries. Given the rate at which battery tech is advancing, the weight of said batteries will likely drop significantly over the next few years.

    Also, the function of the systems at a 2009 trade show doesn’t really bear any relevance, especially given the success so far of Di2 and the paucity of complaints (at least on the internet) about function. Also, Andy Schleck having issues in the TdS is what’s called an N=1 sample set. Did Andy Schleck, his mechanic, or anyone on the team say, “I (Andy) seem(s) to be having issues shifting up front,” or was that just an assumption?

    I don’t see myself ever buying either of the Di2 groups, but that doesn’t mean they are robust systems with excellent performance. I certainly have heard enough friends and acquaintances (racers, non-racers, and weight weenies) sing Di2’s praises.

    I expect that when Campy releases its electronic group (within the next year?), competition between the those companies will drive evolution of those systems pretty quickly.

    Kudos to Shimano for bringing out Ultegra Di2, especially at a price that makes ownership a possibility for more riders.

  8. JD on

    I recently picked up a new bike with DA Di2 and I’m completely sold on the tech. My old bike with Ultegra 6600 components was great but I would always experience a few missed shifts every ride, usually at the most annoying times – e.g. on a descent and trying to grab 11 or 12 or working the middle of the cassette on a climb, killing momentum. I tried fine tuning the RD, replacing cables, having a professional shop tune it, etc but I’d still experience the occasional shifting issue.

    So far, with Di2, I’ve had zero shifting problems. It’s quite amazing to ride and never really have to think about the nuances of your particular drivetrain setup. Just click a button for a gear and go. Rear shifting does *feel* a bit slower but honestly, I think it is more perception than anything because of having to click the button multiple times in rapid succession. It simply takes a bit of getting used to.

    Battery life is a non-issue. Seriously, I don’t get why everyone is worried about a battery that is known to last 3000km or more. Hell, I live in a very hilly area and I’m constantly up and down the cassette and back and forth on the front rings and, so far, at 1000km the battery indicator just started showing 50%. Show me someone that can ride 1000-2000km in one day… The charger is small and the battery is so light that you could carry a spare in your jersey, if you were that anal, without much issue.

    I know the big feature everyone mentions is the FD shifting performance under load, which is true, but that wasn’t the key selling point for me. The big plusses for me are: easy maintenance, ridiculously easy setup of the RD, crazy long battery life, ease of shifting when your hands are tired/numb, no missed shifts (so far), and auto-trim (nice feature.)

    The cons in my opinion are: initial expense and potential replacement costs if you damage the components. With Ultegra Di2, these cons are diminished and when we eventually see 105 Di2, it’ll get even better.

  9. amanda on


    Don’t you know the difference between luddites and retro-grouches?

    Luddites are the ones who’ll try to remove batteries from every Di2s in sight.

  10. Tom on

    best rear shifting system out there by far and best front shifting auto trim feature going. This is the future. Campy falls behind once again. LOL

  11. marrfia on

    I’m 99% sold on di2….for all u knockers out there why don’t u try b4 you say something. Me personally having my gear shifts perfect everytime and no chain rubbing on front deraullier is mega bonus to me…..I can’t stand chain rub sound! Re weight, unless your a pro competing for yellow jersey at a tour then don’t use it as an excuse to knock it! Extra 300grams for us amateurs and cafe cyclist is not going to be a bother. This is biggest step forward in cycling since derailleurs was invented. I’m all for it

  12. marrfia on

    The positives way out number the negatives for going with this system….in fact seriously someone please come up with a real negative against it backed up by basis behind why ! To the people who say mechanical shifts is only true way to go! Bullshit. This di2 is not automatic, you still have to press a button to het s change of gear, your still in the drivers seat making decision….it just going to be a better change every time you tap the button and that’s what I would want for my money’s worth.

  13. James Stroud on

    I loved the shifters at first but last two rides I’ve had a problem. The rear derailer would not shift down to the smaller rings in the back. Last night it happened several times on a group ride and I assumed that maybe I had the shift pressed in the car as it lay on its side and the battery wore down.

    I charged the battery and kept it out of the bike before my crit tonight – tour of washington county in Maryland USA 3/4. Anyway I had huge problems shifting in the rear, it would always go up to the easier gear (larger cog) but I had to hold hold press press about eight times to get it to shift down as my legs spun about 10,000 rpm. Eventually towards the middle of the race it shifted better.

    Tonight I cleaned the drive drain (it was not that dirty) with finish line speed degreaser and re-lubed chain and rear derailer. It shifted fine in the bike stand so we’ll see. Prior to the last 2 nights i was in love w/ ultegra di2 but during my race i was wishing for my old mechanical regular ultegras back

  14. J. Smith on

    There is a great potential for this system for amateur/beginner/occasional riders as well:

    Feasibly, the system could be developed to shift both the front and rear with just one shifter actuation, as needed. For example, as one works up to the larger rear cogs while on the large front ‘ring, the system would drop to the middle ‘ring when appropriate – basically managing both the FD and RD in unison to provide the best chainline and most appropriate gear combo.

    What a boon for rental bikes, etc. :~)



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