The veritable heart of the new XTR Trail drivetrain is a trail tuned triple ring crank crowned with a carbontitanium composite 32 tooth Primary Driving Gearthe go to, most used gear for the widest range of terrain, and the gear your suspension bike was designed around. Dyna Sys combines features like quick shifting CloseStep front gear ratios think: bigger granny, smaller big ring, a wide range 11 to 36 tooth 10 speed cassette and re engineered shifters and derailleurs that are less susceptible to trail chatter or contamination. Together, Shimano Systems Engineering unlocks performance and versatility never before seen in a triple, and it's all tied together with the industry's first mountain bike specific 10 speed chain.Riders who would otherwise have to pull the ripcord and battle technical climbs from the trenches of their granny gear range can now push farther up the trail in their middle ring thanks to the increased range of a 36 tooth low end rear gear. The granny gear is still there, you'll just need it less, and the 42 tooth big ring is more useable and easier to get into than ever before, so you'll use it more. Simply put, XTR Trail is the most efficient mountain bike drivetrain singletrack has ever seen. This 10 speed Dyna Sys cassette combines stiffness with consistently smooth shifting performance and durability in an innovative lightweight package. Refined tooth profile for HG X chain and Shadow RD. 3 piece spider for stiffness under load. 5 titanium cogs.