Shimano BB-RS501 bottom bracket

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.