Shimano's 12-speed rollout brought the 105 groupset in line with Ultegra and Dura-Ace on gear count, and the FC-R7100 is the crank that carries that update into the drivetrain. It uses hollow-forged aluminum arms with Shimano's Hollowtech II two-piece design running on a fixed 24mm axle, paired with an aluminum inner ring and a Hollowglide large chainring reinforced with resin ribs on the backside. The result is a crank built around Shimano's usual priorities—stiffness under load, clean front shifting, and durability that holds up to daily miles.

Chainring options cover the two combinations most road riders actually want: 50-34T compact for climbing-friendly gearing and 52-36T semi-compact for riders who want a taller top end without going full 53-39. Both pair with Shimano's 12-speed HG cassettes, and the front shift ramps are tuned to work with the FD-R7150 Di2 or FD-R7100 mechanical front derailleur. Arm lengths run 160, 165, 170, 172.5, and 175mm.

One thing to know before ordering: the crankset does not include a bottom bracket. You'll need a 24mm Hollowtech II unit matched to your frame's shell—SM-BBR60 for BSA threaded shells, SM-BB72-41B for press-fit BB86, or the Italian-threaded equivalent if that's what your frame calls for. The 44.5mm chainline and 148mm Q-factor are the standard R7100 geometry numbers, so if you're upgrading from an 11-speed 105 or Ultegra crank, expect the pedal stance to sit a touch wider than the outgoing R7000 series.... Read More