Shimano Dura-Ace FC-R9200 Crankset - 170mm, 12-Speed, 54/40t, Hollowtech II Spindle Interface, BlackThe Shimano Dura Ace FC R9200 crank performs two vital functions; transferring your pedaling effort into the drivetrain and ensuring the fastest, most precise front shifting available. With HOLLOWTECH II crank arms to ensure light weight and Shimano's class leading chainring designs, the FC R9200 won't let you down. 54 40t option is designed for the fast racing situations 148mm Q factor 44. 5mm chainline Optimal balance of stiffness, strength, weight