Shimano FC-M820 Saint Crank Arms - 1x10 Speed

Win all kinds of gravity races! 
SHIMANO MODULAR CHAIN DEVICE is tough and efficient chain device. Rider can choose one half guard/two half guards/no guard according to course/usage. It has minimum bash guard for protecting chain and chain ring from impact. And replaceable silencer works less noise, easy focus on your riding. Moreover SHIMANO MODULAR CHAIN DEVICE ensures super stable and silent drivetrain with SHIMANO SHADOW RD+ rear derailleur.

HG-X

Further evolution of shifting performance A directional mountain bike specific 10-speed HG-X chain means smoother shifts, lighter weight and greater overall performance. HG-X directional chain: Outer side is optimized for front shifting and inner side is optimized for rear shifting.

Outer side parts

Inner side parts

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.

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.

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 optimized crankset design on the market.