ULTEGRA's 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 12-speed road lineup, the FC-R8100 crank builds upon Shimano's legendary front shifting and transmission efficiency. With 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.

FEATURES

• 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

TECHNOLOGIES

Hollow technology on outer chainring

• High rigidity hollow structure cuts down on weight yet maintains strength. Better power transfer and quicker and more precise front shifting.

Hollow 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.

HOLLOWTECH II

• Providing the best balance of stiffness, strength, weight and rotating performance

The concept of HOLLOWTECH II technology is focused on producing a superior crankset which will maximize a rider’s power transfer. The rigidity of the crankset ensures pedaling efficiency while its weight, a key element of the crankset, you want light, 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. HOLLOWTECH technology is an ultra-lightweight hollow crankarm created by SHIMANO with the company’s own proprietary forging technology that also maintains rigidity. The addition of HOLLOWTECH II technology integrates the bottom bracket axle with the right crankarm for more stiffness and a weight savings to achieve a high-dimensional balance. Its outboard bottom bracket bearing system provides better weight distribution and more pedaling stability, allowing for more efficient power transfer.

• The HOLLOWTECH II crankset has been developed by pursuing the optimum balance of stiffness & rotating performance in a lightweight and beautiful crankset design.

High Precision Sealing

• Moreover, HOLLOWTECH II crankset has a high-precision sealing in the bearing area to increase durability maintaining the excellent rotating performance for long periods.

24 mm Diameter Axle And Bearings

• Why choose the 24 mm axle and bearings for the HOLLOWTECH II crankset?

The diameter of the Bottom Bracket axle and bearings was of primary importance for the development because the Bottom Bracket axle area is tied to such key elements as stiffness, strength, weight and rotating performance.

What’s important is the total balance of crankset

• In addition, taking the crankset as a whole, the total balance of crankarm rigidity, axle stiffness, bearing position and others is essential.
• Indeed, the crankset is designed by careful consideration of the total balance of those elements to prevent breakage.

Outboard Bearing

• For most frames with 68 mm Bottom Bracket shells, HOLLOWTECH II with 24 mm axle can set the bearing position outside of the frame to provide better weight distribution and more stability.