When developing the XTR M9100 drivetrain, Shimano knew they needed to compete with the wide gearing range offered by SRAM Eagle, so they stepped up to the plate with a whopping 10-51T range on the M9100 “Wide Range” cassette. For those with a keen eye, that’s a 510% gearing range, which slightly edges out SRAM Eagle by 10%. SRAM Eagle cassettes have a 10-50T range, which is just one tooth shy of the XTR cassette. How much will you actually notice that on the trail? Probably not much to be honest, and it’s likely more of a ploy on Shimano’s part to one-up SRAM. Interestingly enough, Shimano is also offering another cassette option for those that aren’t sold on the massive wide range of gears. Dubbed the “Rhythm Step”, this cassette’s range is reduced to 450%, with a 10-45T range. I see this mainly being attractive to the XC-race crowd who are looking to save weight anywhere they can. Not only is the cassette lighter, but it also reduces the length of chain needed to wrap the cassette, which also saves a bit of weight. If gram-counting is your MO, and you don’t need the wide range, this will be your ticket.
Shimano claims the XTR Wide Range cassette offers smoother transition into the largest 51T cog compared to Eagle, mainly because of how they spread out the gear range.
As you can see from the numbers highlighted in green, Shimano opted for a more even spread between gears 9, 10, 11, and 12, with the biggest jump being between 9-10 and 11-12. Notice it’s only a 6T jump though, compared to Eagle which as an 8T jump from gears 11-12. While I’ve never really found it to be much of a drawback, I have heard others complain that they feel the jump to the 50T cog on Eagle is too big, which I can certainly understand. The potential drawback on Shimano’s approach are the bigger jumps between 8-9-10, in comparison to Eagle. If you find that you’re between these gears frequently, you may prefer the shallower steps on SRAM Eagle.
Another topic worth discussing on the M9100 cassette is the claimed ability to shifter under heavy load with little degradation of shifting performance. This is in-part thanks to an update in ramp design on each cog. Shimano is calling it Hyperglide+, which builds upon and improves the previous Hyperglide technology employed on the company’s cassettes since 1988. Another benefit to Hyperglide+ is the addition of down-shift ramps, which is a first for Shimano. Instead of just “dropping” the chain down the next cog when down-shifting, the added down-shift ramps allow a much smoother transition. All of this comes together to provide very smooth and crisp movement between gears, both up and down the cassette. Hyperglide+ tech is also employed on the M9100 chain, which has been updated to increase chain retention. This improved chain retention is required seeing the more extreme angles the chain sits at on either end of the Wide Range cassette.
Construction of the cassette employs “Beam Spider” technology, which conjures up an image of a laser-shooting arachnid in my mind. Alas, neither spiders nor lasers are used in the construction of this cassette. Instead, “Beam Spider” is just a oddly named buzz phrase describing the strategic use of aluminum, titanium, and steel materials for the gear clusters, which are attached to an alloy carrier. To be exact, the three largest cogs are aluminum, the next five are titanium, and the smallest four are steel.
Achieving the expanded gear range of the Wide Range cassette required that Shimano update their freehub design. A 10T cog simply would not physically fit on a standard HG driver, so here we are, onto another new standard. Unless you’re brand new to the mountain bike world, you likely are aware, and fed up with, the rate at which new standards are introduced, strongly encouraging us to upgrade and buy new parts for our bikes. I suppose I shouldn’t complain seeing that it’s a contributing factor in how we make money here at Fanatik, but I can’t help but feel for the consumers out there on limited budgets. Heck, just trying to sort through all the standards of components is an absolute nightmare for the newcomers to this sport. Anyhow, that’s enough ranting, and chances are, if you’re considering XTR, you’re likely not on a super tight budget and/or building up a new bike from scratch.
MicroSpline is Shimano’s new freehub, which effectively will likely replace HG as time goes on, and XTR tech trickles down through XT, SLX, etc. The freehub utilizes 23 splines, which is significantly more than the 13 used on the HG freehub. This disperses the cassette cog load more evenly around the cassette. Heavier riders, and those putting down serious force in their high gears, would often find that the smaller cogs would mar up HG freehubs, sometimes to the point where you couldn’t even remove the cassette without some serious force. The MicroSpline system promises to fix this issue, which I am glad to see.
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