SHIMANO XTR DI2 | $2,575 AS TESTED | SHIMANO.COM
When Shimano released its first electronic road group back in 2009, people had their doubts. My friends and I–all shop mechanics at the time–joked about how we'd have to get a degree in robotics to work on the stuff, and insisted it was a solution to a problem that definitely didn't exist. Shimano already had the best road shifting, and you'd rarely have to replace a shift cable.
The shit-talking was plentiful, but within months of getting it in the shop, nearly every mechanic was a total convert. Aside from running the wires, setup and adjustment was simple as hell, and shift accuracy, reliability, and durability of the system was incredible–far better than cabled shifting. Getting a bunch of grumpy grease monkeys behind this stuff was nothing short of amazing.
Let's get the obvious out of the way: This stuff is super expensive. You can get a solid bike for the price of just this drivetrain. If I had a buck for every time someone said, "that sure is an expensive derailleur hanging out there, what if you smash it on a rock," I'd be able to afford this kit. The thing is, it's not about cost–it never has been with XTR–it's about pushing the envelope of performance. The flagship product is where all the best technologies go first, eventually trickling down to more affordable groups. Besides, I'm thinking that the folks who will buy this can afford a new $650 rear derailleur. Acknowledging that it's costly, I'll move on.
As history shows, mountain bikers have been far more accepting of new technologies than roadies steeped in tradition. Threadless headsets, thru axles, and disc brakes found their way onto mountain bikes first, so you'd think that when it finally hit the mountain bike market, people would accept the idea of electronic shifting with open arms. But, even I, someone with nothing but amazing things to say about Di2, was hesitant to love the new XTR Di2, cost aside. It seemed unnecessarily complicated. I've asked fellow editors and riding buddies, and they all feel the same way. Why?
Something happened to mountain bikes since I first started wishing for Di2 to come over to the dark side: SRAM suddenly made them work a whole lot better by ditching front shifting altogether. Shimano might argue that SRAM's single ring setup doesn't offer enough gear range, but the marketplace would disagree. Take a look at nearly any high-end mountain bike today and chances are it has a one-by drivetrain. Di2 is offering the best front shifting that has ever been available at a time when everyone and their mom is trying to get rid of it in favor of a simpler, quieter drivetrain.
You can run Di2 as a single ring setup–Shimano makes a dedicated one-by crank–but you'd be missing out on a ton of the technology that Di2 has to offer. Plus, you wouldn't get the same range offered by a SRAM one-by. Hesitation about front derailleurs aside, I was curious as hell about the system, especially the Synchronized Shift feature, which through some clever programming allows the use of one shifter to control both derailleurs.
Setup and Adjustment
The Di2 parts of the system consist of the front and rear derailleurs, shifter, or shifters, handlebar display, battery, wires, and junction box. Wiring the system takes up 90 percent of the setup time, but is very straightforward. Since most bikes aren't designed to run Di2 wires, most of the time is spent running and securing the wires to, or in, the frame. Stay tuned for a post with more on the internal wiring process.
Adjusting the shifting is actually easier to learn on Di2 because using the shift paddles to tell the derailleur to move the direction you want it to go is more intuitive than fine-tuning a barrel adjuster–"Which way do I turn it if I want the derailleur to go this way?" To adjust "cable tension," hold down the button on the display until it indicates adjustment mode. Then, tap the shift button associated with the direction that you want the derailleur to shift in. If you're using one shifter, you can still adjust both derailleurs by toggling between them with the button on the display. It's really simple.
XTR Di2 in Action
Having experience with the road stuff, I wasn't surprised to find the shifting to be excellent, but the Synchronized Shift thing was an entirely new beast. Even though I only had one shifter to worry about, my brain had difficulty detaching from the idea that I needed to control the front shifting. I found myself lost in the 22 gears after having gotten used to having just 11. After my first couple rides, I wasn't convinced, but after a couple more I started coming around.
Syncro mode takes you through the entire gear range in just 12 shifts, two more than an 11-speed single ring–the complexity is merely perceived. The front shifting works so seamlessly that the anxiety I felt over the system faded away. The most amazing thing started happening: The front derailleur would shift without me even realizing it. Think about that for a moment. Shimano made front shifting so perfect that it can happen without the rider noticing. This is the same part that riders and mechanics have toiled over for since its invention, and it just disappears into the system? It's simplicity through complexity. Is SRAM more ingenious for getting rid of front shifting altogether, or is Shimano for taking it out of the thought process? I don't know, but the ride experience is relatively the same: a system that lets the rider focus on the riding.
Chain retention is actually pretty good. I can't say the same for the mechanical XTR I've tested so far, but I've rarely dropped the chain on my Di2 group. I can feel pretty confident that after a rowdy descent the chain will still be on the ring I left it. The system can be a bit louder than a single ring, but it's the quietest multi-ring system I've ridden by a long shot.
You must be wondering about battery life. What happens if it dies on a ride? Well, if it does, that shit is on you because the battery life is insane. I've been riding it for months and haven't needed to charge it once. I just went on a weeklong trip with it–I didn't even think about charging it beforehand. I can't even remember where I put the charging cable. In short, it's a non-issue.
The rear derailleur has shrugged off a couple impacts hard enough to scratch it up and bend the hanger without any problems. If you put the Di2 and mechanical derailleurs in a ring together, the Di2 would win every time. It's far more robust and has less slop than it's cabled counterpart.
Since there's no mechanical movement necessary, Shimano could make the shifters look and feel however they wanted. Thankfully, the designers chose to make a lever, as apposed to a simple button. The levers have actual throw and an indented click for each shift. The levers themselves are tactile and feel like they're worth the coin, but I have to admit that the plastic-bodied shifter feels less than robust, and the 2-mil hex set screw has a tough time securing the shifter to the bar.
Getting back to the shift quality, it always feels the same, no matter what the conditions are. With a mechanical shifter, chain tension can affect how hard it is to push the shifter. With Di2, it's always the same. If you click the lever twice, the derailleur will shift twice, no matter what. Shifting is deadly accurate each and every time, even if you're powering up a climb. It's absolutely amazing. Your current shifting might be good, but this stuff is on a whole different level. Do you need it? No. But you don't need full suspension or disc brakes either.
Okay, so Shimano has built tons of flexibility into this group–the problem is that the only way to configure it is on a computer running Windows. It's the most technologically advanced component group ever made and there's only one way to get under the hood. That's just straight-up stupid. If you're like every person in every coffee shop I've been inside in the past five years and you don't have a PC, here's what you won't be able to do:
The software lets you create Syncro shift maps based on any number of riding styles or conditions that let you tell the system at what gear on the cassette you want the front derailleur to shift. The system will hold 2 Syncro shift modes that you can toggle between using the button on the display. The default Syncro modes will take you from the easiest to hardest gear without making a very large jump in cadence. You can change that a bit, but it won't let you get stupid, like having 5 makeup shifts in the back when changing the front. If you're in the small chainring on the default Syncro 2 mode, the system will beep when you get into the fifth cog from the top, indicating that the next shift will be a Syncro shift. The next time you hit the upshift button, it'll take you into the big ring, and will shift to the next easiest gear on the cassette at the same time, which is the system's next harder gear. If you live in a wet climate, you might want to have the system avoid cross chaining and stay in the smaller cogs more often to cut back on noise. The more you ride it, the more ideas you may have to reprogram the shift maps. Or you can always just leave it alone and ride the hell out of it.