It’s no secret. In the last couple years, Shimano has been taking a beating in the mountain bike drivetrain wars — especially at the high end. Just look at the current North American component spec on top tier XC and enduro race bikes from the big three. Giant’s Anthem Advanced Pro 29 0 (XC) and Reign Advanced 0 (enduro) both come stock with SRAM Eagle XX1 drivetrains and SRAM brakes. Same goes for Trek’s Fuel 9.9 Race Shop Limited, Procaliber 9.9 SL Race Shop Limited, and Fuel EX 9.9 29. And just one Specialized halo race bike (Epic XTR Di2) has Shimano parts. All the other upper level Epic, Enduro, and Stumpjumper builds are draped in SRAM components.

So why this glaring disparity? Two words: 12 speed. Indeed, until today Shimano hasn’t had a product to directly compete with the wildly popular 12-speed SRAM Eagle drivetrain, which has all but put an end to front derailleur equipped bikes, at least in the U.S. market. But that will most certainly change in 2019 — and we don’t mean the return of 2x systems.

Behold Shimano XTR M9100, the Japanese giant’s first foray into the 12-speed world. There is a ton is information to get to here, so start scrolling.

The primary new cassette (there are three total) has a 10-51 spread, which equals a 510% gear range or 2% more than SRAM Eagle’s 10-50. The other two new Shimano options are a 10-45 Rhythm Step, which has a 450% range, gentler gear steps, and slightly lower weight, and a 10-45 11-speed cassette, which offers lower weight (310 grams versus 367 grams for the standard 12-speed), but still works on company’s new 12-speed platform.

Using the 11-speed cassette also means fewer total chain links needed (about 6), meaning more shaved weight (about 13 grams), reduced chain slap, better chain retention, and increased ground clearance because you can use the new short cage rear derailleur (more on that later). The 11-speed cassette also plays nice with Shimano’s new wide flange XTR hub (covered here), which reduces weight by 3 grams and allows for a wider spoke bracing angle and more even spoke tension.

All three of these cassettes employ what Shimano calls its Beam Spider construction, where in the case of the 12-speed set-up, aluminum (3 largest cogs), titanium (5 middle cogs), and steel (4 smallest cogs) are used, “for an optimal blend of weight savings, rigidity, and durability,” says Shimano.

The rationale for the three cassette gearing options is simple: choice. Shimano says that in talking with both pro XC and enduro racers, they found that many of them preferred either less weight or better gear steps over wider gear range. And since the “R” in XTR stands for race, Shimano listened. But while choice is nice, Shimano also revealed that 100% of the OEM spec requests for Shimano-equipped bikes slated for the North American market next year were for standard 10-51 set-ups, and that in Europe the number was 95% for 10-51, and just 5% for the other two. Clearly max gear range is what most consumers want — or at least that’s what the bike industry thinks. (Mtbr would have to agree.)

Key point No. 2 focuses on the Hollow Tech II crankset, which will be available with both single and double chainring set-ups. Chainrings are now easily exchanged thanks to a direct-mount system, and cranks can be swapped between single and double front chainring setups.

The single chainrings (round only, no ovals) use a narrow-wide tooth profile and will come in 30t-38t options and two Q-factors, a narrower 162mm that replicates a rider’s road bike position from training, and 168mm for trail/enduro applications. In either case chain line holds at 52mm, meaning Shimano is still supporting non-boost bikes.

If you prefer a 2x set-up (and have a bike that will accommodate it), you’ll get a 38/28 gear combination and again have the choice of 162mm or 168mm Q-factors. Either way, attachment is direct mount with single key release that Shimano says is both lighter and stiffer in part because there are no pinchbolts on the left crankarm. It’s just pressed onto the BB spindle. Shimano has yet to provide any exact crankset weights, but we do have pricing info, which can be found below.

That brings us to important point No. 3. Part of Shimano’s XTR launch includes the debut of Micro-Spline freehub technology. Not surprisingly, Shimano did not adapt SRAM’s XD Driver standard (they don’t make one-piece cassettes was the rationale given), and instead they created something of their own.

As the name suggests, Micro-Spline features smaller freehub splines that allow for use of a 10-tooth cog, which according to Shimano helps eliminate damage/gouging to the lightweight aluminum freehub body. This technology is found on a host of new Shimano XTR and non-series hubs that are detailed in this post. The new XTR brakes are covered here.

It’s also worth noting that there are no wheels in this conversation. Shimano said it decided to focus on their strengths and get their hubs into other people’s rims. That said, DT Swiss is the only other company to have access to the new spline pattern, but not to what Shimano is calling its Scylence system (that’s only available in new Shimano hubs) which delivers 7.6 degrees of engagement for a very direct pedaling feel along with a silent coasting function.

“You really need to experience [the Scylence system] to truly understand,” explained Nick Murdick, Shimano’s North American MTB product manager, who gave the key presentation at the initial XTR press launch at company world HQ in Osaka, Japan, an event attended by Mtbr and small group of other North American mountain bike media. “You can hear how much traction your tires have and it dispels the notion that a loud buzzing noise equals high performance.”

That sounds cool for sure, but the press launch in Japan did not include any testing time, so for now all we can do is report Shimano’s claims. The good news is that in mid-June, the Big Blue S is coming to Mtbr’s Colorado headquarters in Crested Butte, where the North American MTB press will get their first opportunity to experience the new XTR group. Stay tuned for our first ride review.

The new freehub body is constructed of two driver plates that completely disengage when you stop pedaling, thus eliminating any freehub ratchet sounds while coasting. Shimano will offer a variety of hub options, including XTR-level with straight pull, as well as a more affordable non-series hub that also includes a straight pull option. Prices range from $530 for a set of straight pull XTR hubs, to $253 for the standard non-series hub option.

One big question, of course, is what does Micro-Spline mean for all the wheels/hubs that you’ve already paid for? The short answer is that if they’re DT Swiss (or a DT Swiss collaboration, think Roval for instance), then you may have nothing to worry about. “DT did not have to make a new hub shell in order to fit the new freehub body,” explained Murdick. “It’s just a new freehub body that can plug into an existing DT system. So DT hubs can be upgraded by getting a new freehub body.”

Of course, that’s contingent on DT Swiss actually offering the new freehub body as an upgrade, which Mtbr has yet to confirm. We’ll update you on that as soon as we know more.

DT Swiss also makes wheels for lots of other people (remember the Roval example) and Murdick believes that in most instances, those hubs will be okay, too. “But there is not a guarantee that it will be upgradable to the new freehub body,” he conceded. “The issue is that the hub shell could touch if it hangs out over the freehub body, because [with the new Micro-Spline system] we do take up just a little bit more space. So yes, there could be a case where a wheel [with DT Swiss made hubs] is not upgradeable. But I think those will be pretty rare.” Let’s hope so…

Bottom line, XTR M9100 series components won’t be available until fall 2018, so let’s call this an evolving story and move on to key point No. 4, the debut of Shimano’s Hyperglide+ technology, which likely will end up being the primary reason why bike makers and consumers will (or won’t) choose new XTR over Eagle XX1.

Good question. Here’s the Shimano sales pitch. “Building on [our] long history of shifting technology, new XTR M9100 delivers groundbreaking advancements in drivetrain performance with the introduction of Hyperglide+ where the newly redesigned M9100 cassette guides the chain both up and down the cassette, providing faster, smoother shifting in both directions… Adding to XTR M9100’s smooth drivetrain transmission, the new M9100 HG chain features an extended inner link plate that connects seamlessly with new chainring tooth shapes for Shimano’s most efficient drivetrain. The new design reduces natural vibrations normally caused by the inner and outer chain plates rolling onto the chainring and provides better chain engagement, stronger retention, and smoother pedaling.”

Admittedly, the text above is filled with marketing hyperbole. But we know from experience that when Shimano puts its mind to something (especially smooth shifting) they almost always do it really well. Again, though, Mtbr won’t get a chance to test the new group until mid-June.

In the meantime, here’s how Murdick explained Hyperglide+ shifting. “It’s a faster and shockless system,” he said. “Think about out-of-saddle shifting under full load. The jerk you may normally experience is gone. That means smooth acceleration and that makes you faster. It’s not just a pleasurable shifting experience, it’s a true performance enhancer.”

Murdick added that the chain and cassette interface also enhance drivetrain efficiency. “It’s a different kind of shift ramp technology,” he continued. “The chain holds on to the larger cog until the upshift is finished. Power is actually transferred to the next gear sooner because the chain never spends time in the air floating between gears. It’s faster, smoother, and more efficient.”

The chain and chainring interface also helps with efficiency. “The chain has an extended inner link plate, which allowed us to put the inner link plate in contact with every tooth in the chainring. Instead of an only relying on the alternating wide tooth/outer link, narrow tooth/inner link, the inner link touches every tooth for a perfectly consistent driving engagement. That quiets side-to-side vibration.”

Shimano says that for enhanced durability, they are also using a special surface treatment on the new XTR-specific chain, a process that was previously only done on their eBike-specific chain. And yes, the chain has a quick link for easy on-off.

The movement of that chain will primarily be handled by one of three new rear derailleurs, which Shimano says are optimized for wide range cassettes whether using single or double front chainring set-ups. The derailleurs feature bigger 13-tooth pulleys and include Shimano’s Shadow RD+ technology for better chain retention and quieter operation. Each different cage lengths (long and short) is designed for different gear ratios, providing systems to work with the new 10-51 wide range cassette, 10-45 rhythm step cassette, plus another derailleur for 2×12 set-ups.

The RD-M9100-SGS is the long cage rear derailleur with a 51t max cog size. It works with both 10-51 and 10-45 cassettes. RD-M9100-GS (short cage) has a 45t max and works with both 11-speed and 12-speed 10-45 cassettes, offering better ground clearance due to the 28mm shorter cage. Finally RD-M9120-GS is designed for front double chainring setups, has a 45t max cog size and is compatible with 2×12.

All three are claimed to have lower tension at the low gear position, preventing efficiency compromising high chain tension. There is also a protective bumper on the derailleur cage. Add it all up and you have three cassettes, three rear derailleurs, and four different ways to build up your bike with new XTR.

And yes, one of those options includes a front derailleur, which Shimano says is better than ever. Indeed, the side swing front derailleur comes with three mounting options (direct mount, E mount, mid clamp) and all three derailleurs work with 49 and 52mm chain lines, i.e. boost or non-boost.

Controlling the derailleur(s) are Shimano’s new RapidFire Plus shift levers, which are claimed to offer light operation force and more versatility thanks to a new I-Spec EV lever design that features greater flexibility in mounting for a clean and ergonomic cockpit. And for double chainring systems, the lever simplifies front shifting with a lightweight and compact design that shifts up and down with a single lever.

Additionally the SL-M9100-I and SL-M9100 shifters has a claimed 20% quicker lever access time, 35% less shifting operation force compared to M9000, and 14mm slide range and 60-degree rotation for I-SPEC EV. The SL-M9100-IL and SL-M9100-L control front double shifting with a single lever design, have 2-way release with instantaneous push and pull movements, and provide a natural finger position and intuitive shifting operation.

Now that we’ve covered all the key parts, here’s a little comparative price and weight info. Just note that Shimano has yet to provide a complete weight breakdown.

12spd Cassette : Shimano 10-51 – 367g | SRAM 1-50 – 360g

: Shimano 10-51 – 367g | SRAM 1-50 – 360g Rear Derailleur : Shimano Long Cage – 240g | SRAM – 265g

: Shimano Long Cage – 240g | SRAM – 265g Shifter: Shimano – 79g | SRAM – 124g

Shifter : Shimano $130 | SRAM $162

: Shimano $130 | SRAM $162 Rear derailleur : Shimano $260 | SRAM $289

: Shimano $260 | SRAM $289 Crankset : Shimano: $420 | SRAM $455

: Shimano: $420 | SRAM $455 12spd Cassette : Shimano $380 | SRAM $420

: Shimano $380 | SRAM $420 Chain : Shimano $65 | SRAM $85

: Shimano $65 | SRAM $85 Chainring: Shimano $130 | SRAM $99

Without having ridden the new group, it’s hard to say too much about the new XTR. But based on what we’ve seen so far — and what know about Shimano — it’s a pretty safe bet that this new group will do nothing to damage the company’s legacy for making superb high-end mountain bike drivetrains.

And while most riders will default to the standard 10-51 12-speed set-up, the idea that you have some choice is cool, too. I could definitely see a time where the lighter weight 11-speed set-up would make sense (think XC racing on rolling terrain with only short climbs, or an enduro race where the transfers aren’t particularly steep). Why not save a little weight?

The biggest concern is with the new freehub standard. Consumers are sick of the industry’s knack for making things more complicated (and forcing purchases to attain compatibility). But if Shimano’s Murdick is correct about the ease of DT Swiss upgrades, then this won’t be as big a concern. We’ll have to check back on that one.

Of course one thing we’ll all want to see sooner rather than later is a more affordable XT version. And while Murdick wouldn’t reveal too much, he did tell us to expect a second tier 12-speed to launch sometime in 2019.

And that my friends is a wrap on the new Shimano XTR drivetrain — for now. We’ll be posting more as soon as we get some ride time. And again if you want to learn about the other new XTR products, check out this post on brakes and this post on hubs, pedals, and more.

To learn more about the new Shimano XTR drivetrain, head to www.ridextr.com.



