The Shimano XTR M9000 Cassette is the most technologically advanced cassette that Shimano has ever produced. It also bears the widest gear ratio they've ever offered; it's an 11-speed cluster that ranges from 11 to 40 teeth.
In contrast to the SRAM's XX1 wide-ratio cassette, the XTR M9000 cassette is compatible with any 10- or 11-speed Shimano style freehub body; you're not locked into an expensive and proprietary XD driver system. This means that you likely already have wheels that will accept the XTR cassette if you're just thinking of updating your drivetrain.
Shimano made sure that the new XTR cassette is a high-tech material lover's delight. It is made of a smart mix of aluminum, titanium, carbon, and steel. The 40t cog is made of aluminum to shave every extra gram. The next six, 35t - 19t, are shot-peened titanium to offer the best balance of light weight and durability for the middling sizes. And finally the four smallest cogs, 17t -11t, are made of shot-peened and nickel-plated steel for the ultimate in durability. The four largest cogs are riveted to uber-lightweight carbon fiber spiders. One look at the intricate webbing of the arms indicates the serious approach to weight savings and material optimization that Shimano's engineers took. The next four cogs are riveted to anodized aluminum spiders, similar to the spiders on the last generation XTR M980 cassette.
And while Shimano's offering may not offer the same total gear range as the SRAM XX1 10-42t cassette, it's likely that only the dedicated single-ringers out there will notice. And thankfully, Shimano still believes in the benefits of multiple chain rings at the top end of their component range. Not all of us are World Cup XC racers. Right? Run this XTR M9000 cassette with their XTR Trail triple crank and benefit from the widest total gear range that Shimano has ever offered. Part of their motivation to limit the cassette to 11-40t was to minimize the tooth count "jump" between gears near the low end of the cassette. The reason is they felt that jumps that are too large could disturb a rider's rhythm as he pedals down the trail. We couldn't agree more.
The Shimano XTR M9000 Cassette is a technological wonder, and it's worthy of your race or top-end trail machine. Are you worthy? Find out.