Shimano BB-MT801 Bottom Bracket Cups

For Shimano 24mm MTB cranks, the Shimano Deore XT bottom bracket uses high quality sealed bearings and is offered in threaded and pressfit options.

Technology

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

24mm Diameter Axle And Bearings

Why choose the 24mm 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 68mm Bottom Bracket shells, HollowTech II with 24mm axle can set the bearing position outside of the frame to provide better weight distribution and more stability.

24mm Diameter Axle And Bearings Provide Optimum Balance For The Crankset

After studying all these problems thoroughly, we made the decision to adopt the 24mm diameter axle and bearings, which have the optimum balance, for the HollowTech II crankset.

In addition, an examination of the total crankset, including the crankarm and gears, proves the optimum balance of rigidity, weight and rotating performance for the ultimate transfer of power to your bike. HollowTech II is simply the most optimised crankset design on the market.

Features

• Set includes left and right hand cups, spacers, inner cover, and inner O-rings
• Light weight seal structure helps to remove vital grams
• Sealed cups keep out dirt and water
• Maintenance free
• Compatible with 68mm and 73mm shell
• Durable anodised finish
• Easy installation with TL-FC25 tool