SHIMANO – CSR9100 12-25 DURA-ACE CASSETTE 11SPD
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.