Enjoy quicker, more precise front shifting and efficient power transfer thanks to its HOLLOWGLIDE structure. It cuts weights yet maintains stiffness, strength and performance. What’s more, the crank arm length starts at 160mm so smaller riders can benefit from SHIMANO’s legendary shifting.An attractive aluminum crank with hollow arms for lightweight, rigidity, and durabilityThe newly designed crank arms offer an optimized balance between lightweight and efficiency. The crank, formed with hollow aluminum technology, is anodized with a beautiful gloss black anodized finish, giving it a luxurious look. The resin ribs on the back of the chainrings are SHIMANO 105's unique structural design that achieves both thorough weight reduction and crisp shifting performance.Key Features:Optimal balance of stiffness, strength, weight and rotational performanceHOLLOWGLIDE structure cuts weight yet maintains strength for better power transfer and quicker, more precise front shiftingCrank arm length: 160, 165, 170, 172.5, 175 mm Gear combination: 50-34T, 52-36T Q-factor: 148 mm