Now with a 4-arm Hollowtech II design passed down from Ultegra and Dura-Ace, the Shimano 105 FC-5800 50/34T 11-Speed Crankset achieves the perfect balance of lightweight rigidity and power transfer. It’s lighter and more unyielding than its previous 5-arm design and features reinforced construction around the chainring area for an even better stiffness-to-weight ratio. Asymmetric 4-bolt pattern is the same for both compact and standard chainrings, so one crankarm fits all chainrings sizes. The chainrings are also interchangeable with Ultegra and Dura-Ace for even more versatility.

• Hollowtech II design has an optimum balance of lightweight and stiffness for better power transfer and acceleration
• New gear dimensions enhance overall performance
• Improved gearing for less chain touch in small/small combination
• Reinforced construction around the chainring area further improves stiffness-to-weight ratio
• Hyperdrive SG-X chainrings for super smooth front shifting and special tooth profiles, pick-up spikes and ramps help make the front derailleur shifts quiet, easy and trouble-free
• Asymmetric 4-bolt bolt pattern allows standard and compact chainrings to be run on the same crankarm
• Rings are interchangeable between 105, Ultegra and Dura-Ace
• DUAL-SIS compatible
• Bottom bracket not included
• Compatible with Shimano Ultegra SM-BBR60 Bottom Bracket and Shimano Ultegra SM-BB72-41B PressFit Bottom Bracket