Heading out the door? Read this article on the new Outside+ app available now on iOS devices for members! Download the app.
XTR has occupied the top tier in Shimano’s mountain bike range since the first generation decimated the CNC-machined aftermarket world in 1991. Shimano has now announced the new XTR M9100 and M9120 versions, both of which not only incorporate a 12-speed cassette and proprietary freehub standard, but provide some clues on where Shimano will be heading in the years to come.
Many of the new features are virtually guaranteed to eventually make their way to Deore XT downward, and some will likely show up in Shimano’s road range as well. Dura-Ace R9100 still seems so new, for example, but if Shimano maintains its usual release schedule, we’re only twelve months away from seeing the next generation and so this new XTR release is as good as a crystal ball.
As a long-time mountain bike nerd, this article is the result of many annoying questions pointed at Shimano during a two-hour presentation. There are still a few gaps in the information available, but this far-from-succinct article should give you a clear idea of what to expect before the groupsets’ expected September arrival.
Two racing groupsets for cross-country (M9100) and enduro (M9120)
Much like recent generations of XTR and XT, Shimano is launching the new XTR version in two clearly differentiated formats to cover the vastly different needs in competitive mountain biking. However, whereas the two variants were called “Race” and “Trail” before, both XTR versions are now fully aimed at racing, but with one designated for cross-country competition and the other more specifically suited to enduro.
For the cross country racer, there’s the M9100 groupset.
The cross-country groupset (M9100) is all about smooth shifting with more tightly spaced gaps on the cassette, dependable efficiency, and low weight. It’s the groupset you’ll see chosen by endurance racers and anyone else building feathery cross-country and short-travel trail bikes.
Sharing a number of components with the M9100 groupset, enduro and trail riders will be best served with the M9120 groupset.
Meanwhile, XTR M9120 is pitched at the progressive enduro aspect of the sport, where the longer suspension travels and more demanding riding conditions call for increased chain security, more raw braking power, and greater gearing range. Modern enduro racing is nearly as hard on equipment as downhill racing, after all, but participants are also often required to pedal back up to the starting gate, too.
And before we go further, bear in mind that this release of XTR only covers the mechanical version. Yep, that braided steel shift cable is very much still alive. However, I’ll come back to this somewhat surprising news later.
XTR cranked to twelve
SRAM’s single-chainring mountain bike drivetrains are already on their second generation, but Shimano have been stubbornly slow and resistant to change despite flocks of mountain bikers adopting the simplified transmission format en masse. More frame manufacturers are realising the tyre clearance and geometry benefits by specifically designing bikes without front derailleur compatibility, though, and with that, the number of chainrings you have (or don’t) is quickly becoming less of a choice.
The previous XTR generation already included a 1x option, but Shimano was clearly still committed to showing the benefits of a multiple-chainring system with tighter cassette spacing. That all changes with M9100. Shimano XTR now shows a strong preference toward a single-chainring setup, but has now added a 12th sprocket on the cassette. This allows Shimano to greatly increase the total gear range relative to the previous generation of XTR, while still keeping the jump between individual gears as small as possible.
The move to 12-speed is a first for Shimano, but follows SRAM’s Eagle family of 12-speed, 1x-specific mountain bike groupsets, and on the road, Campagnolo’s recent release of 12-speed Record and Super Record. No doubt, this is a sign of things to come for the Japanese firm.
One can’t help but draw comparisons between SRAM’s Eagle 1×12 and Shimano’s new XTR. And yet, while they’re now extremely comparable, Shimano have gone about things in the way Shimano always does – their own way.
Perhaps proving just how much of a wholesale change the new XTR groupsets are, Shimano claim zero compatibility with older generations. You can re-use your stock of gear housing and cables, and your Shimano bottom bracket, too, but that’s about it.
Micro Spline
When SRAM first released their 1x-specific XX1 drivetrain, they did so with a wholly new freehub body design to accommodate the smaller 10T cassette sprocket. This XD driver body was left as an open standard, and literally every single hub and wheel manufacturer adopted it, with the exception of Shimano.
Micro Spline is all new.
Shimano have followed suit in offering new XTR with a 10T small sprocket, but there’s no XD driver here. Instead, Shimano have created Micro Spline, an entirely new freehub body standard and the next generation on the existing Hyperglide (HG) standard that has stood first since 1988. Yep, after 30 years, Shimano’s engineers are moving on.
The Micro Spline design is smaller in diameter to allow for that small 10T cassette sprocket. The new pattern also provides a more precise fit for the cassette and is said to remove the risk of cassette cogs digging into the surface since there’s more contact area. Like the current Hyperglide system, Micro Spline is also direction-specific, so there’s no risk of installing any of the cassette sprockets backwards.
In addition to the size and spline changes, Micro Spline is 0.55mm-wider than the current Hyperglide body. By comparison, Shimano’s move from the original Hyperglide to the road-specific 11-speed version saw the body grow by 1.8mm.
So Shimano has created a wholly new freehub standard, and everyone will just offer aftermarket freehub bodies to suit, much as what happened with SRAM’s XD open standard, right?
That was my thought, too, and unfortunately, I was wrong.
As of right now, the Micro Spline standard is closed, meaning any brand that tries to offer compatibility will potentially be infringing on Shimano’s patent.
Obviously, Shimano will offer new hubs to suit, and the wholly new hub design (more on this later) is a big part of the new XTR launch. However, don’t expect conversion freehubs from Shimano to make this new groupset suit your existing wheels.
All hope isn’t lost, though, as the design has been offered to a single, but large, manufacturing partner: DT Swiss. It’s expected that DT Swiss will produce aftermarket freehubs to suit its popular 3-pawl and Star Ratchet drive systems, which are also found on many other brands of hubs and wheels that use DT Swiss internals.
Given the locked-in nature of the Micro Spline system, it’s safe to assume that every hub manufacturer excluded from the license will work toward having an alternate option. However, it’s currently unclear if SRAM’s Eagle 12-speed cassettes use the same spacing as Shimano’s new cassette, so whether any mixing and matching of components will be possible is to be determined.
New cassettes and chain
The new XTR cassettes are lighter than ever, and unlike anything we’ve seen from Shimano to date – and not just because of the 12-speed format. The largest eight sprockets are fixed together on a “beam spider”, and the three largest of those are made of aluminium; the rest are titanium. The four remaining sprockets are individual steel bits. A freehub lockring, using the existing Shimano HG lockring tool standard, is used to pinch it all together.
The new cassette makes use of aluminium larger cogs, a first for Shimano.
There are two range options, 10-45T and 10-51T, offering 450% and 510% range, respectively. To put that into perspective, Shimano’s M9000 XTR 11-speed in a 2x format using 26/36T chainrings and the 11-40T cassette offered a 505% range.
The 10-45T cassette (10-12-14-16-18-21-24-28-32-36-40-45T) is designed to help riders better maintain their desired pedaling rhythm and cadence with smaller jumps between ratios, something cross-country and marathon racers often prize.
The 10-51T cassette (10-12-14-16-18-21-24-28-33-39-45-51T) is designed for the trail rider, enduro racer, or mountainous marathoner, offering a wider range, but with bigger jumps between its last four sprockets. By comparison, SRAM’s Eagle 12-speed cassette (10-12-14-16-18-21t-24t-28t-32t-36-42-50T) takes a different approach to spreading the 12 gears, treating the 50T as an obvious bailout gear over the next-smallest 42T cog.
Such a large cassette may seem absurd, but consider that it allows the use of a larger chainring, and that even the strongest of riders are likely to see a benefit in the ability to have such a massive gear range in a single-ring system.
The 10-51T cassette is claimed to weight 360g, which is impressively just 30g heavier than the outgoing XTR HG-9001 11-40T cassette. It’s also equal in weight to SRAM’s XX1 Eagle 10-50T cassette (although that cassette’s ingenious PowerDome machined construction allows all but one of the sprockets to be made of steel).
While Shimano haven’t yet published cog width, cog spacing, or chain width, it’s safe to assume it’s all narrower, at least compared to existing 11-speed standards. For that, there’s a new 12-speed chain and 12-speed master link.
The new 12-speed chain features a new extended inner link profile.
The new 12-speed XTR hollow pin chain sees a significant change with the inner link noticeably extended beyond the roller. Such a design offers a few benefits, including a more secure engagement with the chainring and cassette teeth. Additionally, it’s likely the additional material provides greater wear support to the roller, and in turn, the pin. In a similar way to how Shimano improved durability with their 11-speed vs. 10-speed chains by distributing the wear point from the pin to the shouldered inner plates, it’s likely similar gains will be seen again. Despite this additional material, the new narrower chain is claimed to be 5g lighter over 114 links.
Both the chain and cassette carry Shimano’s new Hyperglide+ branding, which is related to new dual-direction shifting ramps and that revised chain shape – all designed for produce smoother and more consistent shifting under power.
As expected, both Shimano and sister parts and accessories company PRO will have an updated range of chain tools out shortly.
New hubs and no noise
Going along with the Hyperglide+ freehub is a new line-up of hubs, which replace Shimano’s long-standing conventional pawl system with a new serviceable aluminium ratchet system called Scylence.
An exploded view of the Scylence system.
The Scylence design’s interlocking toothed rings are similar in concept to that of Chris King’s Ring Drive or DT Swiss’ Star Ratchet, albeit with a few differences in function. Most notably, Scylence completely disengages the ratchet teeth when you’re not pedaling for silent running (hence the name) and presumably reduced friction. When you pedal forward, though, the hooked shape of the drive ring splines help to pull the whole mechanism together.
Scylence is also Shimano’s fastest and most secure engaging hub to date, with 60 ratchet teeth offering a crisp six-degree engagement speed (recent iterations are 10-degree, and before that they were 20-degree). I got to play with an early prototype of the hub, and while there is some friction briefly felt as the system begins to freewheel (likely not present in the production units), the hub then spins incredibly smoothly and quietly afterward (under 30 decibels). With Scylence’s whisper-quiet operation, Shimano now join Onyx in the silent hub game, in stark contrast to the very loud driver designs from Chris King, Industry Nine, and others. The quietness may take some getting used to.
Beyond the Scylence freehub mechanism, the new Shimano hubs and wheels continue on with adjustable cup-and-cone steel bearings instead of the more popular sealed cartridge bearings. From Shimano’s point of view, this open bearing system is better able to handle side forces and offers extended service intervals thanks to the multiple sealing layers. When adjusted correctly, it does roll incredibly smoothly.
However, the system carries two obvious negatives. Neglect your servicing and you risk damaging the races the bearings run on, and unlike a sealed bearing hub, that bearing race is part of the actual hub shell (although in fairness to Shimano, it’s the cone that usually wears out well before the cup part, and those are easily replaced). Secondly, where nearly every other brand has worked out how to keep up with mountain biking’s forever-changing axle standards, Shimano lock you into whatever the hub is sold with. In this sense, Shimano will offer XTR hubs in either 100 or 110mm (Boost) widths and only a 15mm diameter up front. There’s a choice of 142×12 or 148×12 (Boost) for rear hubs, but if you need anything else, such as Pivot’s new 157mm-wide Super Boost+ or a quick release, you’re out of luck.
The new hubs are available in the most common thru-axle variants only. If you require a 20mm-diameter front axle or a different width, you’ll need to look outside of the XTR range.
Available in either 28H or 32H drillings, the hubs will be available in a choice of traditional J-bend or straight-pull flanges (both designed for three-cross lacing). The latter is a new option from Shimano, with straight-pull hubs previously only being found on the company’s complete wheels.
The new freehub system has certainly helped in the weight department, with the 231g rear Boost hub dropping 46g compared to the M9000 version. The matching front hub is 16g lighter, too.
In addition to the new XTR hubs, an OE-specific (original equipment) MT900 hub will be available to bike brands with more subtle branding. This will also be available in J-bend and straight pull, and given how Shimano have closed off its Hyperglide+ freehub to others, it would be safe to assume Shimano hubs will make a resurgence in future bicycle specifications.
Direct-mount crank
In another first for Shimano, the chainring is now directly mounted to the base of the hollow aluminium crank; there’s no longer a spider incorporated into the arm. As has been seen with the likes of Rotor, Race Face, Easton, Cannondale, SRAM, and others, direct-mount chainrings offer lower weights (up to 80g saved, according to Shimano), potentially improved stiffness, and no chance of bolt failure. As an extra benefit, they’re aesthetically very clean, too.
The visual differences between the M9100 (left) and M9120 (right) crankset are minimal. However, the enduro crank uses its additional weight to offer greater stiffness, and its wider Q-factor provides more frame clearance.
Single-ring chainrings will be offered in 30T-38T sizes, in two-tooth increments, all with a refined narrow-wide tooth profile to better mesh with the new chain. The chainrings are held to the crank with a new proprietary lockring system. Shimano will include the tool with aftermarket cranks, and they’ll also be sold separately.
The new XTR looks to the past in how the non-driveside crankarm is attached, ditching Shimano’s twin pinch-bolt system and preload end cap in favour of a self-extracting 8mm hex key system similar to the old XTR M970 version (along with nearly every other mountain bike crankset on the market) And like that old XTR M970 crank, bearing preload is adjustable via a threaded ring that sits between the crankarm and the non-driveside bottom bracket bearing.
The bearing preload adjuster is said to work without the use of tools; just finger tighten and ride.
With the direct-mount system, the new M9100 crank is a substantial 100g lighter than its predecessor, going from 598g to 498g. The Q-factor on these cross-country cranks grows from 158mm to 162mm to better accommodate a wider range of frames, but never fear, a new pedal option can even everything out (more on those in a bit). The M9120 enduro version of the crank is a little wider yet, and also heavier, although the added weight supposedly makes for extra stiffness.
Both M9100 and M9120 versions will be available in Boost or non-Boost variants, with the Boost featuring 3mm of outward offset on the direct-mount chainring. Nearly all variants will be available in a choice of 165, 170, or 175mm lengths.
Lots has changed on the new XTR cranks, but the 24mm-diameter steel spindle remains. There are no changes to bottom bracket options with this generation, and if your frame features a PF30, BB386EVO or similar oversized shell, you’ll still need to find an adaptor solution from outside of Shimano’s catalogue.
Three new chain guides will be available for those seeking absolute chain security.
For riders seeking even further chain security, Shimano have a few XTR-level chain devices (SM-CD800). Available in ISCG05, Direct Mount, or E-type mount, all of these are simple resin top-only guides with a single adjustment screw.
There’s still a 2x option
It’s not evident in Australian or American markets, but there is still some demand for front shifting. And so while XTR now not only matches, but beats, the range of SRAM’s competing product, Shimano will also offer a double chainring option for XTR. For the first time in the XTR lineage, a triple option is nowhere to be seen.
Shimano XTR is now pushing toward 1x drivetrains, but without ignoring 2x users in the process. Chainring options are the biggest limitation.
This 2x setup comes with just a 38/28T chainring combo available to match the 10-45T cassette. To use this setup, a specific long-cage rear derailleur (M9120-SGS) will be needed, too.
The simpler two-chainring format has allowed Shimano to create a new simplified “Mono” front shifter to match. This features a single lever that works with a push/pull motion. Such a design is not only 20g lighter than dual-lever shifters, but it likely frees up bar space for a suspension lockout or dropper remote, too.
The front derailleur borrows a trick from the road range with an integrated cable tension adjustment. Regardless of mounting type, these feature Shimano’s compact “Side Swing” design and drop 10g over the previous generation.
Rear derailleur changes
Shimano’s relatively new direct-mount derailleur standard appears to already be coming to an end, at least for mountain bikes. The new derailleurs once again bolt to a traditional derailleur hanger without any additional connecting links. Carrying over is Shimano’s Shadow Plus layout, which keeps most of the mechanism closely tucked under the bike’s chainstay and includes an adjustable clutch mechanism on the pulley cage for chain security.
The XTR M9100 rear derailleurs are quite different to the previous generation. The medium-cage GS (left) is for use with the 10-45T cassette, while the longer SGS (right) version is designed for the 10-51T cassette.
Pulley wheels grow in size from 11T to 13T, which supposedly help with chain security, but also reduce drivetrain friction since the bigger wheels will spin slower than the smaller ones, and the chain won’t have to articulate as much as before.
In addition to the new 2x-specific derailleur mentioned previously, there will be the choice of medium (GS) or long (SGS) rear derailleur cage lengths. The shorter version is 10-45T-specific, boasting 28mm better ground clearance, the ability to run a shorter chain, and improved chain retention. Those wanting to run the 10-51T cassette will need to use the long-cage derailleur, which can be used with the smaller 10-45T cassette, too.
New I-Spec, a familiar shifter, and a dropper remote
I-Spec is Shimano’s integrated shifter and brake clamp, and was already in its third generation. New XTR M9100 marks the fourth generation of I-Spec, and, perhaps not surprisingly, the new I-Spec EV offers zero backward compatibility.
The new integrated mount was inspired by enduro riders running their brakes in a more flattened “moto” setup for less arm pump when riding steep downhill sections. Rather than compromise the brake lever or shift lever position, I-Spec EV greatly increases the adjustment range to accommodate the wide variation in setups – by four times, in fact. Whereas I-Spec II offered 15 degrees of tunability between the brake and shift lever angles, I-Spec EV now provides 60 degrees, plus an additional 2mm of lateral adjustment for 14mm in total.
Thankfully, Shimano will not force the use of its new I-Spec EV system. The shift levers will be available with a choice of either a band clamp or I-Spec EV, and likewise, the brakes can be used without the shifters, too.
The right-hand shifter itself obviously gains an extra click, but is otherwise a familiar component with Shimano’s Rapidfire Plus, 2-Way Release, and Multi-Release technologies all present. These trademarks effectively mean the shifter allows multiple shifts in either direction, and shifting to smaller cassette sprockets can be done with either your index finger or thumb.
Combined with a revised rear derailleur design, and some low-friction cable technology borrowed from Dura-Ace R9100, the new shifters claim a 20% quicker shift and 35% less shifting effort. Given how snappy M9000 is already, these are impressive figures, and certainly, less shifting effort when a clutch mechanism is involved is never a bad thing.
Shimano’s new MT800-IL dropper post remote.
Having created another I-Spec standard, Shimano will offer its own compatible dropper seatpost remote (MT800-IL) to work with the majority of cable-operated dropper posts on the market. This remote uses a 7mm cable stroke, and like Wolf Tooth’s popular ReMote, this version operates on a sealed bearing for smooth operation. This will be the only I-Spec EV-compatible dropper remote on the market, at least until all the aftermarket dropper post lever makers get their hands on one and produce their own adapters.
Wholly new brakes
Unusually, the handlebar clamp on the new Shimano M9100 and M9120 brakes has been relocated to the center of the lever body. According to Shimano, this increases the rigidity of the brake lever without changing the actual brake lever blade position or operating geometry.
Built for the cross-country racer, the M9100 brakes (left) look to save weight. The M9120 brakes (right) are all about power and control.
The two-piston caliper on the lighter M9100-series brake now features quicker brake engagement with a shorter (non-adjustable) lever stroke and 10% greater lever rigidity. The brake also gets a simpler straight hose connection to the forged aluminium caliper, instead of an adjustable banjo fitting. The stock pads are the same as M9000, meaning finned, non-finned, resin, and metallic options will all be readily available. All told, the new M9100 should save approximately 50g compared to a set of M9000 brakes, while improving function.
For riders that prize stopping power, the XTR M9120s see more substantial changes. These enduro-centric brakes move to a four-piston caliper, providing 10% more braking power than the previous XTR Trail brakes. The new caliper uses a larger brake pad, and while not confirmed, it’s suspected to be the same as the current Shimano Saint pad. Shimano will only offer finned brake pads for this model.
The M9120 brake lever also includes more tunability, with tool-free reach adjustment and free stroke adjustment (basically how far the lever moves before the master cylinder piston starts to push fluid through the hose). No matter how you set the lever up, Shimano’s Servo-Wave variable leverage ratio geometry will help boost the braking power relative to the M9100 once the pads contact the rotor. The lever is said to be 8% stiffer, too.
The new brakes are joined by new rotor designs. These borrow the Ice Tech Freeza technology from the latest Dura-Ace RT-900 rotors, with the aluminium core extending into fins below the braking surface to help dissipate heat. [/caption]
The new rotors are said to manage heat better than before, and they’re also lighter than the previous RT-99 rotors. saving 10g in a 160mm size or 30g in a 203mm. Claimed weights for the 140, 160, 180 and 203mm diameter sizes are 90, 108, 133, and 149g respectively, for 10-30g of savings depending on size. Just like the XTR hubs, these rotors will only be available in a Center Lock mount.
There’s an 11-speed version, too
Not everyone will want or need the increased range of the new XTR 12-speed cassettes; some especially aggressive riders will instead want the increased wheel rigidity and durability that come with more widely spaced spoke flanges. For them, the new XTR groupset will be offered in an 11-speed variant. This one basically just omits the largest sprocket of the 12-speed cassette, but uses the same sprocket-to-sprocket spacing. On this new “Wide Flange Hub”, the driveside spoke flange is pushed outward by 4.7mm relative to the standard 12-speed hubs.
It’s a 12-speed 11-speed drivetrain. Confused? The XTR M9125 is all about widening the hub flange spacing, and to do so, drops the largest 12th cog off the cassette.
Since the cassette spacing is unchanged, all of the other components aside from the specific hub and CS-M9110-11 cassette are shared with the 12-speed system. However, limiting the range to 10-45T allows for a mid-length GS derailleur to be used, which saves a few grams, improves ground clearance, and a chain that’s three to four links shorter.
Such a setup won’t be for everyone, of course, but for heavy-hitting enduro riders that want the very best chain security and wheel stiffness, this will likely be the hot pick.
Potential things still to come: Di2 and wheels
Shimano offered the previous generation of XTR and the current generation of XT in both mechanical and Di2 electronic options. And yet, this new release of XTR is mechanical only.
Given Shimano’s obviously massive investment in Di2 to date, it’s fairly safe to assume there’s more to come. Toby Shingleton, brand manager at Shimano Australia, pointed out that XTR M9000 mechanical was announced before its Di2 sibling, but wouldn’t reveal more than that.
I speculate it’s probably a similar story to that of Campagnolo’s latest 12-speed release, and the next generation of Di2 is taking just a little more development time than its mechanical counterpart.
It’s also quite possible that Shimano are waiting on other pieces of the puzzle, and the long-term goal of Di2 on the mountain bike was always one of healthy integration. As of right now, I’m dreaming of the thought of an integrated electronic dropper seatpost that shares system control and a battery with my rear shifting.
It seems obvious that the closed freehub system will come with a full line-up of new Shimano wheels. However, that’s not the case just yet. As of right now, Shimano have only released standalone hubs, so complete wheelsets are sure to come.
Refined pedal options
The previous XTR pedals were already benchmarks in the category, so it makes sense that the new ones are only slightly different.
With so much else changing in the groupset, the hugely popular XTR SPD pedals receive only minor refinement. Shimano will continue to offer them in a lightweight cross-country race version, and a heavier enduro version with a larger cage.
Both models have slightly wider platforms for better support and stability. The mechanism is also a little more open than before to help shed more mud. The M9120 enduro pedal also gets a new surface treatment for improved durability, and both models are more heavily machined than before. Weights have not been supplied, but we suspect they’re a few grams lighter.
For riders stressed about the increased crank Q-factor, the new XTR M9100 cross-country pedals will be offered with optional spindles that are 4mm shorter to make up the difference – just the opposite of the extended spindles available in the Dura-Ace R9100 SPD-SL road pedals.
Complete weight breakdown
All told, the new groupsets are lighter than the previous generation. The 1x cross-country configuration is approximately 150g less than before, despite the extra cassette sprocket and far greater gearing range. That figure is a far more impressive 400g (approximate) if you’re comparing the new wide-range 1×12 setup to the older 2×11 groupset. Compared to SRAM’s XX1 Eagle, the M9100 1x groupset is approximately 15g lighter (including Shimano’s new hubs compared to using the slightly lighter DT Swiss 240s with SRAM) – basically a wash.
The harder-hitting enduro-focused XTR groupset drops about 90g compared to the previous XTR Trail M9020 range. And it’s within 10g of SRAM’s X01 Eagle, though the gap widens in favour of Shimano when the brakes and hubs aren’t included.
Retail prices haven’t been confirmed yet, but it’s expected to be within 5% of the existing 9000 series. Groupsets will be available around September 2018, although some sponsored riders will likely be on it at the UCI World Cup round in Nove Mesto this weekend.
