Bicycle Crank Folding Aluminum Alloy Crank Arm Length 170mm Durable Mountain Bike Bolt Circle Diameter BCD: 130mm Fits All Speed Road Bikes Bicycle Chainring Protector Sprocket Set 45T-BlackMade of Aluminum AlloyThis bicycle crank is made of aluminum alloy for ultimate strength and reliability. [Crank arm length] Crank arm length 170mm, fixed with 5 bolts. FoldingThis bicycle crankset suitable for folding bicycles allows you to drive more efficiently. [Bolt Circle Diameter] Bolt Circle Diameter (BCD): 130mm, fits all speed road bikes. CompatibilityThis bicycle crank is an ideal replacement for bike repair, compatible with many bike