Shimano 105 FC-R7100 105 CranksetThe Shimano 105 FC R7100 crankset offers an optimized balance between lightweight and efficiency without sacrificing stiffness. The crank is formed with hollow aluminum technology and finished with a durable gloss black anodized. The resin ribs on the back of the chainrings are Shimano 105's unique structural design that achieves both through weight reduction and crisp shifting performance. Optimal balance of stiffness, strength, weight and rotational