If we were to compare Shimano to an animal, it would probably be the komondo dragon. No-- we're not saying it's not sleek like a panther, or graceful like a bird of prey, but rather that it illustrates a level of patience known to few other creatures, slowly and methodically planning and stalking for its moment of attack. Its designers took their time calculating every possibility when designing Shimano's new 12-speed drivetrain, and it shows the second you take a peek at the all new XTR CS-M9100 12-Speed Cassette. With more than one cassette range option, Shimano's 12-speed cassette blows us out of the water, offering both a close-step 10 - 45-tooth range for intensely precise cross-country applications, and the beefier 10-51 that offers you the ultimate bail out cog for tedious climbs up steep fire roads. Unlike other 12-speed groupsets, Shimano builds the CS-M9100 cassette to play well with both 1-by and 2-by applications, so you don't have to feel limited to a gear range that doesn't optimally suit you. Both cassettes are built to pair up with Shimano's Microspline freehub interface, allowing for room for that extra 10-tooth cog. When it comes to ramping, we have to say that Shimano's 12-speed cassette pushed well beyond our expectations. It features Hyperglide+ rear cogs with guide ramps on both sides of its surfaces, which pairs with its proprietary chain that is capable of engaging two cogs simultaneously during both upshifts and downshifts, enabling faster upshifts that take just one third of the time of previous, non Hypergide+ groupsets. The cassette features aluminum outer cogs, titanium mid-range cogs, and steel inner cogs that are all riveted to a cold-forged aluminum beam spider to keep weight at a minimum, while offering the durability you need on the cogs that get the most abuse.