Shimano BB-MT501 BSA Bottom Bracket

Hollowtech II

A perfect balance of stiffness, strength, weight, and efficiency. Hollowtech II technology is designed to produce a superior crankset that maximizes power transfer. The crankset's stiffness ensures pedaling efficiency, while its lightness, a key element of the crankset, helps the rider on long distances where more pedaling is required. Naturally, Shimano has made every effort to ensure a super lightweight and extremely stiff crankset, two goals that conflict with each other. Hollowtech technology, which consists of an ultralight hollow crank arm that maintains stiffness, was developed by Shimano using its exclusive forging technologies. The addition of Hollowtech II technology integrates the bottom bracket axle with the right crank arm, ensuring greater stiffness, weight reduction, and high dimensional stability. The bottom bracket's axial bearing system ensures better weight distribution, resulting in more efficient power transfer. The Hollowtech II crankset was developed pursuing an optimal balance between stiffness and rolling performance, achieving an ultralight and very elegant design.