Shimano FC-R8000 Ultegra 11-speed double chainset, 52 / 36T 170 mm

From Shimano:

• The HollowTech II 11-speed Ultegra chainset offers an ideal balance of light weight and stiffness, making it the perfect choice for both enthusiast and competitive riders
• HollowGlide hollow outer chainring gives vast improvements in rigidity by virtually removing outer chainring flex and hugely improves shift performance, even under high load
• The chainring teeth have been developed to work in conjunction with 11-speed HG-EV chains for increased contact to provide greater efficiency and improved power transfer
• Industry leading HollowTech II cold forged 4 arm hollow cranks have been evolved for maximum rigidity while reducing weight
• Wide gear pitch spacing increases clearance between chain and leading teeth to provide compatibility to frames with O.L.D. 135 / 142 mm and 410mm chain stay length
• A wide range of chainring options and crank arm lengths are available to meet the needs of all riders and racing disciplines
• HollowTech II integrated bottom bracket uses a wider bearing placement and larger axle diameter for increased stiffness and efficiency
• HollowTech II integrated bottom bracket seal design has minimal bearing interface ensuring smooth rolling and increased durability(sold separately)