About 12 months ago, Shimano released a much-anticipated version of XTR – the new 12-speed M9100. It offered what so many people wanted – a wider range from Shimano, and they delivered with a 10-51 cassette.
But they also delivered a 10-45 cassette, 4-pot XTR Trail brakes and a lighter Race brake, a new crank set, new freehub design and 38t chainrings, a silent running hub and a drivetrain with claimed improvements in efficiency. The only problem was availability. While Jolanda Neff and Mathieu van der Poel were on XTR M9100, it was pretty thin on the ground.
There have been some reasons behind that, with equipment loss in fires at a factory being the main problem, and in the case of the new hub design, having it made in commercial quantities sounds like it just hasn’t been viable – yet.
Regardless, our MarathonMTB.com Team have recently updated our bikes to XTR M9100 12-speed. Make no mistake, 11-speed M9000 and M9050 XTR Di2 were awesome group sets. But even with an 11-46 XT cassette, it was possible to come up short on gear range, spinning out in fast starts or riding agonisingly low cadences on steep climbs. Not always, but sometimes.
Doing the upgrade to XTR M9100
We have 3 2020 Norco Revolver FS frames on order for our team. They are stiffer, have updated geometry and Boost spacing. They’re just not available yet.
With our current Norco Revolver 29 FS frames being non-boost, we were reliant on using any wheels we had with DT Swiss hubs, as opposed to the new Shimano XTR hubs which are Boost only. DT Swiss are one of a few manufacturers allowed to make the Microspline free hub. It’s a bit lighter than the normal Shimano spline freehub (56g vs 69g), and it allows the use of the 10t sprocket.
Swapping this is out was easy, and a good opportunity to put some fresh DT Swiss Special grease on the star ratchet.
The whole group is pretty neat, although we are using the MT900 crank – which is a stop gap for shortages of the M9100 crank. It is essentially the same system as the regular Hollowtech II crank, with two pinch bolts and the preload cap.
A couple of nice changes include bolts with a thicker head (less likely to round out) and of course the direct mount chain ring. The cranks come with a tool that works with their BB tool, but also has flats for a massive spanner – or a bench vice.
On the scales there is a 2g difference compared to the M9000 crank being removed, with the MT900 crank being that tiny bit heavier. The M9100 crank is said to have a considerable weight saving thanks to its construction.
Shifting and braking
There’s a big difference at the controls, as the Shimano M9100 group set moves to what Shimano call iSpec EV. It’s a new iSpec mount with 60 degrees of angular rotation to get your shifter placed right where you want it while it attaches to your brake lever. Now this can then move inboard and outboard, so it’s a huge range of adjustment.
But the brake levers themselves are very different. The clamp has moved inboard with a contact point where the clamp used to be. It is essentially a trick of the eye, but it means the lever braces against two points of the bars and feels much stiffer.
These are the Race brakes with a two-piston design. The Enduro model has 4 pistons and the ServoWave lever and adjustments that the XTR Trail brake had – along with a change in the lever blade height. The calipers on the Race brakes are lighter and have a fixed banjo position. We had about 2-3g difference between the M9000 Race brakes and the stock M9100 brakes.
One thing with the shifter moving from Di2 is getting the MultiRelease back, being able to shift a couple of gears at once each way, and use the upshift lever with a forefinger or thumb is very easy to get used to again. With cable and outer the shifter is 185g, about 2g heavier than a Di2 shifter with all the electronics required to make Di2 work.
The XTR M9100 derailleur
There are two models available, a short and long cage. We have the long cage to use with the 10-51 cassette. The 10-45 cassette only needs a short cage (GS) rear derailleur but we have opted for the wider range with hilly races like the Swiss Epic and maybe Marathon World Championships in Graechen, Switzerland on the horizon for our team.
The M9100 SGS derailleur has larger jockey wheels than the M9000 or M9050 models, and at 243g it’s lighter than the 289g Di2 model. The GS model is lighter again. A lot of the design will act the same. It’s Shadow Plus to stay out of harms way, it has an adjustable clutch that can be flicked on or off, and the B-tension, high and low limit screws are all easy to reach. The cable clamp is newer and points the cable away from the spokes.
Introducing Hyperglide Plus
The 10-51 M9100 cassette is 374g, super light compared to an XT 11-46 at 439g. The 10-45 is lighter again. The chain’s weight is similar – especially when you consider you might have a link or two more. Here the largest sprockets are aluminium, then the next are Ti with the smallest four being steel.
The chain and cassette, and chain ring, are actually some of the most interesting parts of the group set. Yes it is 12-speed, yes it has more range than SRAM Eagle. But the shifting is so smooth and quiet, and how the bike pedals and shifts under load is too.
If you’re a bike nerd you have heard of Hyperglide. It’s what Shimano does to help move the chain to a larger chainring or sprocket. Moving to a smaller one has really been based on the derailleur knocking the chain off a larger sprocket. Hyperglide Plus optimises the teeth shapes and ramps, and the surfaces of the chain to make the shifter happen smoother and faster. The shift is completed within a shorter arc on the cassette, and it does so more securely.
The chain is 12-speed specific and part of Hyperglide Plus, shaped to shift smoothly with the cassette and also engage with the teeth of the chainring like glue. The Siltec coating helps make it last and actually helps keen it quiet as well.
Setting it all up
This was as you’d expect, and really no different to M9000. The cable and outer are slick and once the routing is sorted for a given frame and the outer cut to length, it’s like any other system.
The brakes are the same, with easy hose trimming after attaching them, with just a bucket bleed done to release any sneaky air.
Chain length is a little different, but only as it’s probably best to adjust to have the length right by how it sits in the 10t. It’s almost a case of having it run as long as possible, compared to as short as possible.
On the trail with XTR M9100
At first, there’s not a huge difference, to be frank. XTR M9000 and XTR M9050 have been amazing group sets. The range is obviously a lot broader than before.
The drivetrain is really quiet when shifting. The noise that can occuer in lower gears on the 11-speed groups with the chain crossing over is non-existent. But it’s once you’re off the driveway test and onto dirt that it all falls into place.
XTR M9100 shifts under load better than XTR Di2. Di2 will just get the shift done, but M9100 does it faster and potentially more securely depending on conditions and the load it’s under.
What’s even cooler is how secure XTR M9100 is when moving to the higher gears. You can shift two gears at once and it moves over really precisely. It’s a small difference but one that is amplified the more you are pushing. The R in XTR does stand for racing after all.
The bike shown here is Imogen Smith’s race bike, and while she did a couple of rides before racing it, it was put in a bike bag for Port to Port soon after being prepped.
“This was my first time racing with Shimano 12 speed. I have a 10-51 cassette and I chose a 34 tooth chainring,” said Imogen. “I have never raced a 34 before – I’ve always opted for a 32, but with the expanded range of gears it was great to have that bigger gearing to play with and definitely helped me a lot on the descents, where it was my job to keep up with a big guy who weighs 28 kilograms more than I do. I never felt overgeared either, because the 51 is just so generous, and it meant that I could ride pretty much everything that the five days of racing threw at me.”
“I was also super happy with the shifting action – I actually barely noticed a difference between my old Di2 XTR group set and the new mechanical 12-speed. A great achievement for Shimano.”
Having ridden both M9100 and then moving back to Di2 on my hardtail, I will say it has made the difference more noticeable. My first rides on M9100 were on familiar trails, without the need for dumping gears or general mistreatment. I always knew what was coming. More time since then has shown how well XTR M9100 responded to aggressive use.
But it has been doing some rides on my hardtail with a 3 year old Di2 group that has really shown the difference – primarily in the shift speed and drivetrain smoothness. The shift on XTR M9100 feels far more secure, and is quiet and smooth – along with delivering a huge range. And the positive is that with all the weight differences tallied, the group set parts came out 104g lighter than the XTR Di2 group for Imogen’s bike shown here.
We have a lot more training, racing and general messing around to do with Shimano XTR M9100 – but so far I’m really impressed. XTR Di2 was an amazing group set, but with the amount we travel there’s a little more certainty for a mechanical group set. But regardless of that, the performance under load is a huge step forward, and one that needs to be ridden.
If you see one of us at a race or on the trail – just ask us how it’s going!