Dura-Ace CS-R9100 11 Spd.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