Palm Springs became a favorite winter resort for Hollywood's beautiful rich for good reason. Temperatures here rarely dip below 70 degrees and there is always a patch of blue sky peeking through when the rest of California is blanketed by angry clouds and pelted by rain. But, we didn’t come here to be seen at fancy restaurants or sip umbrella cocktails at swim-up bars. Palm Springs sits at the foot of Mount San Jacinto, one of Southern California’s tallest peaks. Mountains flank the city like a formidible wall of stone, and hidden within their folds is an extensive and little known trail network. We were here to put Shimano's electric Di2 XTR drivetrain to task in a very unforgiving desert environment.
Pinkbike, along with a hand-picked cadre of editors from North American media outlets, were invited by Shimano to take possession of the bikes of our choice, outfitted with electric shifting Di2 M9050 XTR drivetrain components. The plan was to familiarize ourselves with Di2’s variety of options and tuning features, then ride and repeat until each of us found a configuration that matched our riding styles. While they were at it, Shimano pimped out the bikes with its Pro cockpit accessories and its huge-for-Shimano, 24-millimeter inner-width, XTR Trail wheelset. Without question, many in attendance were riding bikes that were more valuable than their daily drivers.
Programmable shift controls: What We learned at Shimano Di2 Camp
Di2 for XTR was launched last year,
but Shimano took their time releasing it, presumably to be sure that its product and support were in place before the media started talking about it in earnest. We will post an extended review after we get sufficient time on Di2 on our home trails, but in the meantime, if you want the short version of how Shimano’s Di2 XTR gets to it on the dirt, it put in a very convincing performance. I chose a Pivot Mach 4 Carbon
to test Di2, because I am familiar with the bike, and also because Pivot was on board with Shimano since the inception of Di2 and as such, was the first brand to integrate it into a frame design with internal wiring and a hidden battery. Pivot designed molded plastic ports where the wires enter or exit the frame - one kit for Di2, and another for cables and hoses. The installation looks very tidy.
Shimano’s contribution to the Pivot beyond its Di2 derailleurs and shifters was an entire XTR M9020 trail ensemble, including brakes with Freeza rotors (160mm R, 180mm F),
a 36 by 26 double crankset, carbon-laminate Trail wheels, and pedals. The bar, stem, and saddle were Shimano’s Pro components. Suspension was all Fox Float Kashima, and Fox also kicked in the dropper posts. The entire bike, including the Shimano XTR Trail pedals weighed 12.52 KG (27.5 pounds),
which was two pounds heavier than expected. Most of that excess heft was attributable to the enduro-weight Vittoria Goma TNT tires that Shimano selected to prevail against the desert's pointy plants, and rocks that glinted like knife blades.
Di2 can be configured to shift in a number of ways. I chose to use a conventional arrangement to begin with to establish a base line, with the downshift button on top and the up-shift button below on the right side and the opposite configuration on the left. Shimano representative Nick Legan plugged my bike into a laptop computer and ran me through some of the options available. Shimano's E Tube software
is free and easy to use, with clear prompts and click-box toggles to switch functions.
Any button can be used for any function. Nick said that some riders program both buttons to shift like paddles on a sports car – all up on one side of the bar and all down on the other. After giving the conventional arrangement a go, I opted to ditch the left shifter altogether and use the right lever to do all the tasks
– which does not require any programming. Just tap a small button beneath the handlebar-mounted display twice to choose either of the two “synchronized” mode options. In 'synchro’ mode, hold down a button and Di2 will march all the way across the cassette, automatically choosing the most effective gear combinations, while making automatic cross-over shifts and trim corrections at the front derailleur. It’s pretty cool to watch
Noises, planned and otherwise: Shifting Speed:
Shifting speeds can be set in one of five options from “very slow” to “very fast” modes. In the two fast modes, the derailleurs get the job done in an impressively short time. Shimano says that riders with slow cadences, however, should avoid the faster shifting options, because the front changer can over-shift in extreme cases and derail the chain.No Mac version yet:
Presently, Shimano’s free E Tube Di2 software
only works with later model PC computers. A Mac version is said to be in the works, but there is no date set for its release.Display options:
I despise hand-held devices, or any computerized thing that requires a long sequence of programming to set up. Fortunately, Di2 is not one of those. The handlebar-mounted display only lights up for an interval when a shift is called for, or when its mode button is pushed. While riding, the display indicates remaining battery life, which of the eleven cogs you are using out back, and which chainring you may have selected, but nobody gives a crap about that at 30kph on a narrow trail. The better use of the display is to switch shifting modes and make adjustments. Battery life is rarely a concern. Reportedly, burn times are averaging well over four months.
Two taps on the button cycles it through “manual” shifting mode, which allows the rider to hit any gear combination he or she wants; or to either “synchro one” or “synchro two” shifting modes, which are both pre-programmed to shift sequentially, using an optimized selection of the cassette and chainring sprockets. S-1 keeps the chain in the big chainring longer, while S-2 mode favors the small chainring when using the lowest gears. Self-healing derailleur:
There is also an emergency “saver” mode that restores the rear derailleur to life. Should a crash or an impact threaten the rear derailleur, it automatically disconnects from the power source and disengages the motor drive. Switching to the SV “saver” mode and holding the button down restores power to the rear mech and causes it to seek out its last position to restore accurate shifting.On-the-fly adjustments:
Holding the display button down brings up the lateral adjustment modes for the derailleurs. Tap one button to adjust right, the other to adjust left. Plus or minus numbers indicate how far you have moved the changer from zero position. It was very intuitive to learn and use.Battery and UST charger:
Shimano abandoned its clunky Di2 charger and instead, uses a USB-type interface that plugs into the handlebar display and functions as both a charging and a programming cable. The lithium ion Di2 battery comes in a slender, cylindrical version that can be slipped into a conventional frame’s seat tube or mounted externally, parallel to a water bottle on the down tube. The smaller, internally mounted battery option that Pivot uses allows frame designers to be more creative with where and how the battery is stashed in the frame. Pivot mounts the battery to a screw-in plate beneath the down tube of the Mach 4 to conceal the power source.
To provide feedback, Di2 shift buttons produce an audible click that can be sensed by the thumbs. Shimano also programmed in warning beeps; One beep to let you know when you have reached the end of the line and there are no smaller or larger cassette cogs available. Two beeps to warn that a double shift is next in line. Double shifts make a crunch and a snap as the powerful front changer switches chainrings and the rear mech moves the chain over two cogs. The beep at the lowest end is the most often heard - and Di2's most disappointing sound. The front changer’s motor is quite loud, while the rear mech’s is rarely noticed. What is never heard, though, is the rattle of the chain links on the front derailleur cage, as Di2’s computer makes quick and sure lateral compensations while the chain is being shifted across the eleven-cog cassette. Beyond the whirr of the servo motors, Di2 runs silently.Optimized shift action:
Because the derailleurs are controlled by a computer, Di2 moves the chain at a rate that optimizes the locations of the gates and ramps on the sprockets, so it can be shifted under full power without too much uttering from below. Good thing, because while becoming familiar with Di2’s two-button selectors, I shifted a handful of gears in the wrong direction more than a few times, and was forced to reverse back to my intended selection while mashing Shimano’s carefully profiled steel 11-speed chain against a paycheck’s worth of titanium teeth. Typically, my transmission party foul would take place on the face of a steep, techy climb, but Di2's recovery was swift, and the derailleurs could march through a handful of shifts quickly enough to keep me in the game. Consistent steps between gears:
Shimano admits that there are a number of redundant gear selections within its 22-speed two-by-eleven drivetrain, but that is intentional. When in manual shifting mode, the rider can leave the front derailleur in either chainring and enjoy closely-spaced jumps that average close to 13-percent while shifting across the 11 by 40-tooth cassette. Using synchronized shift mode, Di2 preselects the transmission's most efficient gear combinations (it turns out that there are 13 of them)
and jockeys the chain between the two chainrings, double-shifting both changers to avoid the draggy cross-chain options. Consistent steps between shifts take some of the workload from tired legs and gives the drivetrain a very precise feel on trail. In case you wanted to know, the cassette ratios are: 11-13-15-17-19-21-24-27-31-35-40T.
Di2 First Impressions:
Di2 XTR Component Weights:
• Front derailleur (D-type): 115 grams
• Rear derailleur (GS): 289 grams
• System display: 30 grams
• Shift switch: 64 grams
• Battery Module: 51 grams
How Di2 components stack up against mechanical XTR:
• Front derailleur: Di2 is 5 grams lighter
• Rear Derailleur: Di2 is 68 grams heavier
• Shift lever: Di2 is 36 grams lighter (if you just use one, it is 136 grams lighter)
• Battery Module: 51 grams (extra item)
• System display: 30 grams (extra item)
|When I tested the first Di2 Dura-Ace on the road, I was sure that I could shift a manual transmission equally well, but on pavement, there is more time to react and fewer distractions than one encounters riding on the dirt. After spending trail time on Di2 XTR, I don't think I could manually shift through a two-by-eleven transmission and consistently hit all the sweet gear ratios, and that's what Di2 does best. You still have to push the correct button, however, but the learning curve is short and I expect to be seamless with the new shifting configuration after a proper long-term review. I can say with surety that, after putting in a long day on desert singletrack, the reduced workload that Di2 shifting brought to the game was readily apparent. I was changing gears much more often, taking advantage of Shimano's cleverly crafted shifting sequence, which uses only 13 of the two-by-eleven's 22 available gears. The feel was distinctly Shimano, with over-the-top ergonomics and controls that seemed to always be at the ready. Still, I was left with some unanswered questions. One of which was: Why, with 22 gears available, does XTR M9050 only produce one click taller and one click lower than SRAM's XX1 does with only 11 speeds? Another was: Considering that Di2 can be controlled with a single shift pod, if there is no weight penalty, then why would there be any downside to running a two-by drivetrain over a one-by? Only time on the bike will provide those answers, so check back in a couple of months for the final verdict on Shimano's turning-point electronic transmission. - RC |
OPINION: Why Electric Shifting?
Mountain bike development has reached a fork in the road, where new bike buyers are being asked to choose new technologies and accessories that promise to make riding easier at the expense of reliance upon electronics and more complicated mechanical components, or to choose technology which has evolved in a linear progression, from cycling’s traditional more organically based mechanical roots. No single product better captures the essence of this crisis of opportunity than Shimano’s Di2 XTR.
Shimano made it absolutely clear at the launch that they had no intentions of ramming electric shifting down every mountain biker’s throat. Their up-to-the-minute, 11-speed mechanical M9000 and M9020 ensembles are proof enough that Shimano understands that the lion's share of today's elite mountain bikers are either unprepared, or unwilling to move forward with Di2. So long as riders call out for more refined mechanically-actuated drivetrains, Shimano will answer as it always has: first with XTR and later with mirrored technology in its more affordable groups. We have learned to trust mechanical shifting largely because of Shimano’s commitment to it, which begs the question: “Why would they move forward with a new, largely unpopular electric shifting system while they were ruling the world with their mechanical know-how?”
The answer may be staring us in the face. The most oft’ quoted reasons for sticking with mechanical shifting are that it is simpler and that any good mechanic can fix it should the worst occur. But is that true today? Mechanical shifting systems may seem to be more easily understandable, but in the quest for perfect gear changes, the inner workings of trigger shifters have become more like timepieces, front changers are twisted like dowsing rods, sprockets have ramps and shifting aids that look like patterns on exotic shellfish, and the parts count of a modern mechanical drivetrain numbers near the hundreds. Most mechanics would not take the time to repair a broken shift lever or derailleur, even if the parts were available. Today’s mechanical shifting is the equivalent of the typewriter: human-powered, elegant, complicated, finely tuned, and somehow, evolution has made it reliable - I have one stashed somewhere, I think.
Di2 is actually a far simpler mechanism. Firmware replaces ratchets, pawls, bearings and springs. Software eliminates guesswork. Buttons replace levers, and a single wire connects all of Di2’s components. Servo-motors communicate with each other and precisely repeat each shift action, so human error is taken out of the loop. Di2 takes care of trimming the front derailleur, and it automatically makes the double shifts to avoid cross-chain situations. Di2 has far less parts, it can successfully operate in worse weather than its mechanical counterpart, and it can better survive crashes. But, the selling points of Di2 are applications that lie beyond the reach of a mechanical system.
If you want simple, Di2 can be programmed with two touches of its display key to shift through every useful gear, consecutively, using only the right-side buttons. Keep a shift button depressed and it will march through all 13 of the Di2’s useful gear selections. Lose the use of your right thumb? No worries. Download Shimano’s free software, plug in the USB charge cable and you can move all the functions to the left-side buttons. Shimano added options in there for remote suspension functions, and when a partner is chosen, Di2 owners will see the day when lowering your dropper post will automatically unlock your suspension’s pedaling platform and fully extend its travel - or vice versa. Di2 promises to do all those things and more with a pair of compact shift buttons and one internally routed wire. To duplicate those functions mechanically would add so many levers and cables to the front of the bike that it would look like a cheap Hollywood sci-fi prop.
So, we have made our way back to the premise of this sidebar. There are an equal number of riders who would choose a mechanical system for its perceived simplicity and reliability as there are potential customers who would not balk at replacing an electronic component if it failed, and who would gladly choose the no-brainer precision of push-button shifting. Certainly, for those who want all the extras, like one-touch shifting, remote droppers, remote suspension controls and the option to personalize those functions, Di2’s electronic solution represents the simplest way to achieve those ends. That said, those who prefer a more basic cockpit layout will not suffer an indigestible reduction in performance by sticking with mechanical shifting and one or two cable or hydraulically actuated remote accessories. The difference lies in the future of each strategy. Once each group has chosen their technology, it is doubtful that their paths will cross again.
View full-size and additional images in the feature gallery.