Shimano XT 3x10 Hollowtech II Crankset FC-780 is like its 770 predecessor in many ways, notably the Hollowtech II construction that ensures its stiffness, strength, and lightness. However, XT 780 cranks are now available as 2x10 or 3x10 configurations like the one here. Compared to XT cranks of old, the tooth differential across the chainring set has been minimized and the chainrings are optimized for use with Shimano's HG-X 10-speed chain.
The premise of the 3x10 gear configuration is that you can have a huge overall gear spread with improved performance. Part of this comes with the move to 24/32/42 tooth chainrings. The smaller jumps between the chainring tooth counts make the front shifting better than ever, yet you'll still get all the "granny gear" you need if you use it with the available 36t rear cog. Upping the cool factor for these cranks is the carbon-encasing-steel sandwich for the middle chainring. It stiffens up the ring and helps it last longer.
The Hollowtech II arms have been reshaped with an asymmetric design that's different yet evokes the sophistication of XTR. The right arm is pressed together with the hollow 24mm spindle at the factory, and the splined left crankarm mates to the spindle during installation and is secured with perhaps Shimano's best detail -- two pinch bolts to secure the arm once the bearing preload is dialed in perfectly. In our experience, it's a superior design in terms of installation, performance, and durability.
The Shimano XT 3x10 Hollowtech II Crankset FC-780 is Black and has a 104/64mm bolt circle diameter. The outer two rings are ramped and pinned for easier shifting. It's available in 165-180mm lengths in 5mm increments, and the bottom bracket is included.