It may have taken a while, but the final piece of our XTR puzzle has finally arrived. If you’ve been following along, Shimano initially shipped out their early XTR M9100 groups with a non-series crankset to speed up delivery. This MT900 crank borrowed a lot from existing Hollowtech II cranksets, but included the new direct mount chainrings that are 12 speed compatible.
And while the MT900 crankset was an excellent temporary replacement due to its stealth appearance and bargain price tag, Shimano is now shipping the original M9100 crankset making the full group available for purchase. Coincidentally, we also just received our full XT test group which we’ll dig into very soon. Shown above is the FC-M9120-1 crankset which is meant for Enduro riding, while the FC-M9100-1 is meant for XC racing (q-factor being the main difference between the two at 162mm vs 168mm).
One of the biggest design changes for the crank is the move to a preload adjustment system that sits inside of the left crankarm. You install the crank by fully tightening the 8mm crank bolt to 45-55Nm and then remove any play by turning the adjustment nut by hand. It’s important to note that certain cranks use different spacer configurations – the FC-M9120-1 uses an included spacer between the left crank arm and the bottom bracket.
With all the included hardware, the cranks measure 472g in a 170mm length without a chainring.
The direct mount chainring are offered in 30, 32, 34, 36, and 38t configurations, all meant for the new 12 speed Shimano chains.
The mounting spline is keyed so you can only install the chainring in one orientation, and you’ll need the TL-FC41 FC installation tool to tighten the lockring. For XTR, this tool was included in the box with the crank.
Our 32t ring checked in at 70g.
Note that you’ll also need a new adapter in order to install the SM-BB93 bottom bracket. Since the cups are physically smaller, they won’t fit the existing Hollowtech BB tools. The adapter ring slips over the BB shell, and then allows you to use your existing TL-FC32 or TL-FC37 tools to install the cups.
The threaded BB checks in at 64g.
If you prefer the look or the price of the MT900 crankset, you’re looking at 595g for a 170mm crank with a 32t chainring. So the higher end M9120 crank will save you 53g.
Out back, the massive 10-51t CS-M9100-12 cassette weighs in at 368g. The 10-51t cassette has a 10-12-14-16-18-21-24-28-33-39-45-51T progression with five titanium cogs, 3 aluminum cogs, and four steel cogs.
You’ll need a Shimano XTR CN-M9100 12 speed chain if you want to take full advantage of the Hyperglide+ shifting (trust us, you do). This full length chain with a little packaging and master link checks in at 271g.
Running that chain through the gears is the massive RD-M9100-SGS which is needed for the 51t cassettes. This is the long cage version, the short cage GS only clears up to a 45t cog. 242g for this derailleur.
Controlling that derailleur up front is the SL-M9100-IR shift lever which in this case is the I-Spec EV mount. The shifter includes multi-release, instant release, and 2-way release functions and will allow for up to four shifts at a time with the main lever. The shifter comes in at 126g with a polymer coated stainless steel shift cable, and the full length OT-SP41 housing adds another 59g.
To use the I-Spec EV shifter mount, you’ll need compatible brakes like the BR-M9120/BL-M9120. These are the four piston trail/enduro brakes which include pads with radiator fins in either resin or metal, ceramic pistons, and ti hardware. The brakes weigh in at 292g and 278g based on the hose lengths.
Shimano of course recommends those brakes to be used with the RT-MT900 Freez Ice Tech rotors. These come in 140, 160, 180, and 203mm sizes, with the 180 measuring 129g and the 203 measuring 148g.
To go along with the group, Shimano sent over their revised XTR hubs which lost their Scylence feature – though they’re still nearly silent. These are impressively light at 144g for the front and 245g for the rear hub in Boost 110/148mm sizes.
There’s also a new SL-MT800-IL dropper seat post lever which is a scant 37g. The lever seems to offer excellent ergonomics and adjustment. Unfortunately ours shipped without the I-Spec EV mounting post, which also wasn’t included with the front brake lever. So if you’re planning on running this, make sure you sort that out ahead of time.
With the exception of the new crankset, we’ve been racking up the miles on the new group on one exceptional build. More on that dream bike very soon…