An integral part of the Shimano Ultegra 12-speed road lineup, the FC-R8100 crankset builds upon Shimano's legendary front shifting and transmission efficiency. With new refinements for seamless 12-speed shifting, the Ultegra crank is now offered in a wide variety of lengths, bringing performance and improved fit for smaller riders, triathletes, and riders with specific biomechanic requirements. 148mm Q-factor. 44.5mm chainline. Optimal balance of stiffness, strength, weight and rotational performance. Hollowglide structure cuts weight yet maintains strength for better power transfer and quicker, more precise front shifting.