Shimano's groupsets often often miss call-outs for European elegance or relentless pursuit of weight loss at all cost and innovation for innovation's sake, instead earning their loyal following through the incredible dependability and meticulous engineering of the Dura-Ace CS-R9100 11-Speed Cassette. 9100 isn't a typo there, it is, in fact, a newly reworked version of Dura-Ace. When the brand introduces a new groupset, you can be sure it's actually boasting improvements you don't have to be Porte or Stannard to detect on a routine Sunday in the saddle. The latest release of Dura-Ace 9100 delivers subtle, thoughtful tweaks to an already intelligent collection of moving parts, retaining the romance of mechanical shifting that's becoming less common each year. The cassette adds new combinations of gearing options, including expanded options for gearing appropriate to rouleurs, climbers, and the puncheurs who demand the best of both worlds. Shimano saw no need to improve the cassette's feathery construction, trusting the same proven combination of titanium and nickel-plated steel cogs and an alloy and carbon carrier that Dura-Ace 7900 introduced two generations ago. Since Dura-Ace is the top-tier drivetrain in the Shimano road lineup, you might be surprised that only the largest five cogs are titanium. That's because--though it's lighter--titanium is generally more prone to wear than nickel-plated steel, and the smaller cogs are more prone to wear than the larger. Because of these material properties, Shimano only uses titanium where the softer metal doesn't create a significant negative impact.