[Lifetime Warranty] Crank Left Arm with Diamond Hole, 170mm Aluminium Alloy Bicycle Crank Arm Left Replacement for Mountain Bike Road Bike (Black)

170mm Aluminum Alloy Bicycle Left Crank Arm Key Features High-Strength Aluminum Alloy:Forged from premium aluminum alloy to provide a high strength-to-weight ratio, ensuring durability and resistance to deformation under pedaling pressure. Diamond Hole Interface:Precision-machined diamond (square) hole mounting point for a secure and stable connection to the bottom bracket spindle. Standard 170mm Length:Universal 170mm crank arm length provides an optimal balance between leverage and ground clearance for various cycling disciplines. Precision Finish:Features a smooth black anodized coating to protect against oxidation, corrosion, and wear from environmental exposure. Replaces / Cross-Reference Part Numbers Product Type:Left-side (non-drive) bicycle crank arm Compatibility Standard:Diamond / Square Taper interface Specifications:170mm length, Diamond orientation Compatibility & Fitment This replacement crank arm is designed for bicycles equipped with a square taper bottom bracket. It is compatible with a wide range of bike types: Mountain Bikes (MTB):Fits most entry-level to mid-range mountain bikes requiring a 170mm arm. Road Bikes:Compatible with road cycling cranksets using the diamond-hole configuration. Hybrid & City Bikes:Ideal for commuter bikes and cruisers with standard square taper spindles. Important Note:This is aDiamond Holeorientation. Verify your existing right-side crank arm orientation (Diamond vs. Square) to ensure matching pedal alignment. When to Replace Stripped Pedal Threads:The 9/16" threads are damaged, preventing the pedal from staying securely attached. Loose Mounting Hole:The internal diamond hole has rounded out, causing the crank arm to wobble on the spindle. Bent Arm:Visible misalignment or striking of the chainstay due to impact or heavy stress. Cracking:Stress fractures near the mounting point or pedal eyelet, which can lead to catastrophic failure. Installation Tips Check Orientation:Ensure your bottom bracket spindle is oriented as a "Diamond" (the square point faces the arm) to match this component. Thread Direction:The left-side pedal isleft-hand threaded(turns counter-clockwise to tighten). Do not force the pedal into the threads. Torque Specification:Tighten the crank arm bolt to the manufacturer's recommended torque (usually 35-45 Nm) to prevent the arm from loosening during use. Grease the Threads:Apply a small amount of bicycle grease to the pedal threads and the mounting bolt to prevent seizing and facilitate future removal. Re-Tighten:After your first 20-50 miles of riding, check the mounting bolt and tighten if necessary, as new aluminum arms can "settle" on the steel spindle.