Since posting my recent acquisition of the new Di2 XTR on another thread, there have been a number of calls for an honest “commoners” review. Hopefully I can do it justice. Here goes…
The price is big, very big. The “budget” version cost in the region of R35k. What is the budget version you may ask? It includes: new XTR 9500 rear cassette (11 speed, which I understand is Shimano’s new standard); an XTR trail crank with 2x on the front; Di2 front derailleur for the 2x; Di2 rear derailleur for the 11 back; Di2 battery; Pro Tharsis XC seatpost specially designed to house the Di2 battery; junction box; Di2 XTR display unit; XTR 9500 compatible chain; Di2 battery charger; single Di2 shifter on the right (I elected not to take the left shifter for the chainring for reasons you will see later); and Di2 wireset. All of these components are advertised as being cutting edge in terms of technology and materials… which of course comes at a premium.
Display unit/brain
My LBS installed the groupset for me, and did a great job I might add. It looks very clean given that most of the wiring is run internally on my Epic.
The night before picking my bike up from my LBS, with new groupset being installed, I loaded the Windows-based Shimano software and ran through the manual. The whole system looked completely customisable through the Shimano program and I wondered where I would start tinkering first.
I picked my bike up the next afternoon, trembling with excitement. Although it was late in the afternoon and bitterly cold in Jozi, nothing could keep me away from a short 5km test-run along the Spruit.
Right shifter for the rear derailleur.
Through the display unit (which is the brain of the groupset) 3 settings have been pre-programmed. There is the manual program where you shift the front derailleur yourself using the second shifter (which I decided not to install). The first synchronized setting is S1, which is setup for a faster, more aggressive ride. Basically, what this allows for, is the automated shifting between the large and small chainrings, depending on gear ratios. Mine has been setup to shift from the large to small chainring when trying to shift past the biggest gear on the cassette (gear 1). As the front derailleur shifts the large chainring to the small, it simultaneously shifts two gears up (smaller) on the cassette into 3rd gear. You then have 2 more gears on the small chainring as you move into granny gear. I was initially a little worried about the front and back shifting simultaneously, but it was entirely smooth.
As I picked up the pace, I shifted up the cassette with a simple click of the shifter. The shifter-click is electronic and virtually taps over rather than having to “push” as with mechanical shifting. It was so easy to shift that I sometimes double shifted, a hangover from the habit of mechanical gears. After I became more familiar with the shifter, this happened less and less. When I shifted to gear 7 or so, the S1 setting decided it was time to shift the front from the small to the large chainring. Again, a simultaneous shift between the back and front, and again, completely smooth. From there I simply tapped through to gear 11 as I screamed down a Delta park section.
The only way I could tell I was changing gears was through the display unit that “turns on” with every shift (and then “sleeps” 5 seconds later to save battery power); the clicking of the shifter; the occasional sci-fi “whrr” of the servo; and the change in power to the pedal stroke. The shifting of the chain between gears was inaudible and I couldn’t feel it through the cranks, not in the slightest. Think of gear paddles on a high-end sports car. You tap paddles on the side of the steering wheel to shift up and down gears – the power ratio shifts, but everything else is seamless. You wouldn’t know the difference except for the change in tone of the engine.
Front derailleur with 2x XTR trail crank
Synchronized setting S2 works similarly, but the gear change ratios are setup more for climbing environments. In other words, the shift down to the small chainring happens earlier in gear 3 or 4, and the shift up to the big chainring occurs later in gear 8 or 9. Of course, settings S1 and S2 are completely customisable, so you can decide when the shift between chainrings occurs depending on your riding style. You can also tap a button at the bottom of the display unit while riding, to move between the settings. I found no reason to move out of the S1 setting.
At first I thought that the manual setting would allow me to change the chainrings from the same shifter that controls the back gears. I understand that this is not the case. If you want the ability to change the front chainrings manually, I am told that you will need the left shifter. I can’t see myself wanting to shift from the automated synchronised settings to manual, and a left shifter will only be a waste of space on the handlebar and money. I can always have a left shifter installed at a later stage if I change my mind, but that would be like installing a manual gearbox in a car next to an automatic gear box… there just in case I felt that an automatic gearbox wasn’t giving me what I needed. Having said that, I am told that some of the pros riding Di2 on the XC World Cup circuit have opted to install the left shifter for that added control. I am not a pro, I don’t need it and don’t want it at this stage.
I returned home after my maiden Di2 voyage and plugged the charger unit into the display unit. On the other end was my laptop with the Shimano software. It took me a bit of time to recognise what component codes relate to what items installed on my bike, until I figured out that the recognition software actually tells you what it picks up. I am not sure why they do not just refer to the components by their commonly known names rather than by codes. I am not sure why it needs my input in the first place, if it can pick up what is there automatically. Anyway, after figuring the components out, I clicked on the customisable features and tinkered with the derailleur settings, as one would with a barrel adjustor, or when setting the high low screws on a derailleur. Although you can do this “in the bush” through the display unit if necessary, it is easier to do with a laptop. After playing around, I returned the settings to the LBS settings that had been set for me. I was satisfied that I could quite easily adjust the derailleurs for perfect settings with the click of a button or two.
The only change that I did make, due to a personal preference, was to reverse the paddles on the shifter, so that the bottom paddle changed up the gears (from large to small cog), and the top paddle changed down the gears (from small to large cog). This too, was as easy a two clicks on the laptop screen.
Rear derailleur with x11 cassette
The Shimano software will also detect whether the components’ firmware needs to be updated, and automatically update the software when connected to the internet. Pretty similar to how your app store identifies and then updates apps on your iPhone. Quick and painless. I believe that future updates of firmware will allow for greater features to be added to the Di2 system. It already has the option for the electric Fox shock system connection – controlling lockout etc from the display unit. It won’t be long before the shock system will read which gear you are in and adjust the lockout accordingly.
So far, other than the steep price, it’s all extremely positive. Beyond my expectations. But wait, the real clincher for me is yet to be revealed. You know that feeling when you have just bought a new bike, with a great new groupset. Those gears shift so smoothly. Jump forward a year and some long tough rides later with a fall here and there – the cables gather dirt, sometimes crimp, stretch a little with time and use. You can fiddle with the derailleur settings all you want, but you can’t quite replicate the smooth gear changes you experienced when the groupset was new. Move forward another year and you develop a bit of chainrub here and there. The “solution” is often a cleaning or replacement of the cables. But let’s be honest, how many of us want that effort. We often clank along until it becomes unbearable and then deliver our bikes to our LBS with a strict instruction to “make it like new again”. In my experience, and no matter what the LBS does, it is never as clean and smooth as it was when it was new. If the Di2 myth is to be believed, that disappointment is a thing of the past.
Pro Tharsis XC seatpost which houses the battery
Because the gears are shifted through a servo, rather than cables that suffer from dirt and fatigue, the system is designed to stay as smooth and crisp as when it was first installed. Only time will tell if this is true, but if it is, that in itself justifies the price tag for me. Oh, and on that chainrub thing, another little trick with the Di2 is autotrim, allowing the front derailleur to shift ever so slightly as you get closer to the outside gears of the cassette, cleverly designed to avoid any chainrub issue that may develop down the line on a mechanical system. It does this automatically, secretly directed from the brain/display, to the front derailleur servo.
For those of you that are weight sensitive, the Di2 XTR is reported to be fractionally lighter than the mechanical version, despite the inclusion of a display unit, junction box and battery. This is achieved through the use of only one shifter, and the fact that the electronic wires are much lighter than the cable equivalents of the mechanical version.
“How long will the battery last?” is a common question. I am told that it is good for at least 300kms, which is more than any stage race I have ridden. If I need more mileage, I simply plug it in to recharge as I would my iPhone. In the unlikely event that I forget to monitor the battery status bar on the display unit and lose battery-life mid-ride, well, people at Shimano far smarter than me have thought about that as well. When the battery runs low, a warning beep will sound that signals enough power for a final shift of the front derailleur. You have about an hour more battery-life left before a second warning beep sounds to signal enough power for a shift of the rear derailleur. And then its single speed baby, until a recharge. If you were worried about not being able to recharge the battery overnight during a multi-stage event, it is easy enough to buy a second battery and slip it into the seatpost. I can’t see that I will need to do this and will probably take a powermonkey rechargeable powersupply with me for an overnight recharge of the Di2 system, just as a precaution.
The verdict
If you can justify spending R35k on a hobby/sport, it is a no-brainer. If you can’t afford that pricetag, wait for the trickle down to XT. From what I have read, that may be as far away as 5 years time, and I personally am not prepared to wait that long. Now that I have it, I would want it more if I didn’t have it, if that makes sense. This is the future, this is bigger than the fad move from 26er to 29er, from tubes to tubeless, from 2/3×10 to 1×11, from seatpost to dropper. In my view, this is the single greatest advance in the sport that I have seen during my time riding. I was way behind the times when it came to the 29er shift, I want to be at the cutting edge of this move.
What happens if you damage the "display unit" in a crash? Will the group set still function? 
I heard about a recent XT release but thought it was this...
https://www.bikehub.co.za/index.php?/topic/149718-Shimano-DEORE-XT-11-speed-and-1x11-option-unveiled