XTR Di2 performed seamlessly in the rugged desert terrain of Palm Springs, CA

XTR Di2 performed seamlessly in the rugged desert terrain of Palm Springs, CA. (click to enlarge)​

I've spent the last six weeks riding Shimano's XTR Di2 electronic shifting mechanism so it's time for an in-depth report. My test rig is a Pivot Mach 4 with 115mm travel equipped with FOX suspension and all Shimano parts. The testing area was the Palm Springs, CA desert and the redwood forests of Santa Cruz and Woodside, CA.

I didn't know I needed 2x11

I've been a diehard 1x11 fan and have been preaching about its glory to all that would listen. I've even converted a couple of 2x10 bikes in the stable to those extended range 1x10's and Narrow/Wide front. I haven't been pleased with the performance of the conversion setups but certainly understand its value proposition for folks upgrading existing bikes in the stable. For 1x11, I've been 90% happy with the drivetrain and occasionally run out of gearing on the steep climbs. But at 150 lbs and a former singlespeeder, I'd usually make most climbs. What I really liked was the lack of the front shifter. That allowed me to focus on riding and it freed up prime real estate on the left handlebar side so my left hand could focus on activating the dropper lever under the bar.

did several rides in Palm Spring, CA. Terrain was extremely rugged, especially the Palm Canyon Epic route shown here.

Gear range and simplicity

Color me surprised as I got on a 2x11 Di2 setup I actually liked and utilized the full gear range. Just as I did in my singlespeed days, it turns out I adjusted my riding style towards my available gearing on my other 1x11 bikes. When the climbing got real steep and long, I just put on my big boy pants and mashed up the climbs. I would use every fiber in my body to get up the steeps. Or in defeat, I'd just walk. Then at home, I'd swap out that 34 tooth front ring for a 32, or a 30 or even a 28. But as the front rings got smaller, the spin efficiency seemed to suffer a bit.

So as I got on the Di2 2x11, I actually enjoyed the gearing range. It was cool to stay in the big ring on the flats and rollers and spin. Then as the trail got steep, I'd get on the lower gears with effortless, perfect shifts. I'd make the climbs and I'd still have a gear or two to spare. Or I would just rest even during a climb, a steep one at that. It was refreshing to have my choice of gearing back.

The key to all this is Di2 allowed me to get rid of the front shifter using Syncro Shift. This is a computerized logic that tells both shifters when to shift the front ring and how much to adjust the rear gearing to match the previous gear. There's two Syncro Modes available with the system and a completely programmable mode is available as well. This is the magic of Di2 as it gives you the range and the simplicity.

The Di2 display is a 30 gram unit that displays the current gear and can select the shift mode.  It shuts off after a few seconds to save battery life.

The Di2 display is a 30 gram unit that displays the current gear and can select the shift mode. It shuts off after a few seconds to save battery life. (click to enlarge)​

Electronics, batteries and other complexity

My big fear with Di2 was that my ride would be overrun by complex wires, displays and battery anxiety. Living with this system, I then realized that the complexity is in the installation, not in the riding. There's a small new array of parts and standards during setup and installation but that's really for the mechanic to figure out.

My job was to ride, pedal and push the triggers. That was it, really. This latest system worked better than any other before it. There's no barrel adjusters, trimming the left shifter, worrying about cross-chaining. I just pressed the shift buttons and it seemed to never run out of gears. It would jump between the big and the small ring on its own and it gave me an audible 'beep' if the next shift was going to cause a front ring shift. The shifting was always perfect and I never heard any rubbing or popping from the chain. Since there's no mechanical cables to wear out, stretch or loosen, the system is more consistent over time.

And what about the pain in the rear battery charging? Well I've ridden the bike for a solid six weeks, about 3 times a week and it looks like I still have 3 out of 5 bars left on the initial battery charge. There's a visual LED screen indicating the gear that I'm in but I never actually look at it. Why should I? I never run out of gear anyway. It turns on momentarily after a shift then it shuts itself off after a few of seconds.

Continue to page 2 for more impressions and specs on Shimano Di2 XTR »

The Di2 battery is stealthily housed inside the frame of some bikes.  For any other bike, a  'Sharpie' sized black cylinder is bolted near the water bottle holder.

The Di2 battery is stealthily housed inside the frame of some bikes. For any other bike, a 'Sharpie' shaped black cylinder is bolted near the water bottle holder. (click to enlarge)​

Configurability is ready for me

Now that I've used this system for a while, I'm actually ready to configure it. I want to reverse the up and down shift buttons. And I want it to shift out of the small front ring a little sooner. And I want it to shift match a little heavier when dropping in to the small ring. And this and that and so on. The good news is the Shimano XTR Di2 system can do all that. It is configurable in so many different ways. I just need a PC compatible computer to do it.

Better front shifting and gear spacing

It's worth mentioning that the front shifting is better than anything I've experienced before. The front rings are more closely spaced together in number of teeth so the drop in torque and cadence is not as 'momentum robbing' as before. The fact that it shift matches the rear instantly helps as well too. Also, having a motor execute the shift perfectly each time means there is no delay or inconsistency in the execution of the shift.

Gearing on the Di2 never seems to run out so steep climbs are handled with the right tool.

Gearing on the Di2 never seems to run out so steep climbs are all up to the rider now, not the drivetrain. (click to enlarge)​

Gear spacing is not something I've been too concerned about but it certainly is improved with the Di2. With 11 cogs assigned to cover 11-40 teeth, the spacing between each shift seems really smooth and consistent. One can shift away during a climb or descent and not experience gaps in cadence or abrupt demands on power delivery.

What about the elements?

Mud, grime and dust haven't been an issue at all. The system seems really robust as there's no sensitive cables and housing for dirt to contaminate. The rear derailleur too seems really tucked away with the frame so it is less vulnerable to rocks and debris tearing it away. As far as weather and the elements, I take comfort in the fact that this Di2 system has been used on road bikes for several years now. The pros have put these systems through the worst conditions so I'm confident they've designed competent weatherproofing in the system now.

The Di2 XTR Crank has chainrings that are ideally spaced for 11 speed so the jump between them is not harsh.

The Di2 XTR Crank has chainrings that are ideally spaced for 11 speed so the jump between them is not harsh. (click to enlarge)​

What didn't I like?

Well, the cost for Di2 is prohibitive for most and we'll detail that later. There is a benefit for sure but the cost/benefit calculation is not compelling for a lot of riders until this technology trickles down.

Out of the box, up and down shift triggers seem reversed, much like Rapid-Rise. Given that there's always many bikes in the stable with shifting in the traditional format, this seems odd that this is the default setting. Of course I understand that it's configurable. But default settings most often stick so it makes sense to reverse the logic out of the box.

XTR is available in Di2 and mechanical versions.

XTR is available in Di2 and mechanical versions. (click to enlarge)​

Another quibble is configuring Di2 can only be done using a PC-compatible machine. This is just stating the obvious but Mac users are common now and these folks get the shakes when they have to touch a PC. And of course, like a GoPro or any other modern piece of electronic wizardry, this Di2 brain should be configurable via smartphone or tablet.

Another weakness is the 11-40 rear cog range is not quite wide enough. We can understand that 11 is the smallest cog to make the it compatible with current hubs. But it would be nice to have a 42 tooth cog so the rider can stay on the big front ring longer. This would be highly desirable too for the 1x11 version of XTR.

Di2 can be left bone-stock or it can be customized to  your heart's content.

Di2 can be left bone-stock or it can be customized to your heart's content. (click to enlarge)​

Di2 XTR component weights

  • Battery Module: 51 grams
  • System display: 30 grams
  • Front derailleur (D-type): 115 grams
  • Rear derailleur (GS): 289 grams
  • Shift Lever: 64 grams

Comparison with mechanical version of XTR

  • Additional Battery Module: +51 grams
  • Additional System display: +30 grams
  • Front derailleur: Di2 is -5 grams
  • Rear Derailleur: Di2 is +68 grams
  • Shift lever: Di2 is -36 grams lighter (if you just the right shifter, it is -136 grams)

The Pivot Mach 4 shown here with full Di2 weighs in at 25.5 lbs.

The Pivot Mach 4 shown here with full Di2 weighs in at 25.5 lbs. (click to enlarge)​

Integration possibilities

Another Pivot Mach 4 we tested had the FOX iCTD system installed where the CTD functions were electronically controlled by a separate switch beside the grip. Climb, Trail, and Descend modes are actually a lot more useable when it's at your fingertips and the front and rear can be synchronized. The FOX system shares the battery and the display screen with the Shimano XTR Di2.

Bottom line

Is it a compelling product? Yes, it is the best shifting system I've ever used and it is as simple and seamless as I need. Value-wise, it is an expensive group indeed so the other bikes in my stable will not get this drivetrain treatment until the technology trickles down to the other Shimano lines. But with its configurability and integration possibilities, the system can grow with my changing needs and preferences.

For more information visit www.ridextr.com.