Shimano's Ultegra FC-R8100 crank maintains the same quick, precise front shifting and efficient power transfer that Shimano riders have grown accustomed to, but with even more crank arm length options. Spanning 160 to 175 mm in length, Ultegra cranks now cater to smaller riders, triathletes, and cyclists curious about shorter crank arms. An integral part of Shimano's new 12-Speed road lineup, the FC-R8100 crank 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 lengths from 160 to 175 mm, bringing performance and improved fit for smaller riders, triathletes, and riders with specific biomechanical requirements. Hollowglide Chainring Technology Hollow technology on the outer chainring. The Hollowglide construction ensures high rigidity while its hollow structure cuts down on weight yet maintains strength. This provides better power transfer and quicker and more precise front shifting performance. Hollowtech II Forged Crank Arms A lightweight crankset not only reduces the bike’s weight but decreases rotating mass to aid in acceleration. The challenge is to reduce the weight of the crank without reducing its strength and rigidity. Shimano's advanced forging technology has solved the problem through the HOLLOWTECH crank. Just like high-quality frame tubing, a hollow crank arm can provide amazing strength and rigidity at very lightweight. Optimised Balance of Stiffness, Strength and Weight The concept of Hollowtech II technology is focused on producing a superior crankset that will maximize a rider’s power transfer. The rigidity of the crankset ensures pedalling efficiency while its low weight, a key element of the crankset, aids in cycling longer distances over which the rider needs to pedal more. Naturally, Shimano strove for the optimum balance between the conflicting needs of stiffness while producing a lightweight crank. The addition of Hollowtech II technology integrates the bottom bracket axle with the right crankarm for more stiffness and weight savings to achieve a high-dimensional balance. Its outboard bottom bracket bearing system provides better weight distribution and more pedalling stability, allowing for more efficient power transfer.