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. 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.