Shimano XT BB-MT801 Hollowtech II threaded bottom bracket for cranksets with 24 mm integrated bearing axle and 68/73 mm shell width. With better sealing and rotation the SHIMANO DEORE XT bottom bracket delivers high driving efficiency. Product features - Shimano BB-MT801 Use: MTB Model: BB-MT801 / BB-MT801-K BB-Type: HOLLOWTECH II Threaded: BSA Shell diameter: BSA (BC 1.37) Mounting: Threaded (for chain case) Threaded BB shell width (choose variant) 68/73mm (BB-MT801) Compatibility XT FC-M8100 / FC-M8120 / FC-M8130 / FC-M8000 / FC-T8000 SLX FC-M7100 / FC-M7120 / FC-M7130 / FC-M7000 FC-MT700 FC-MT610 FC-MT600 Material Aluminum Weight 84g (manufacturer information) Technology HOLLOWTECH II 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.