How do you measure wire rope?

• A. Across the widest part
• B. Along the length
• C. Around the circumference
• D. Across the narrowest part

Answer: (A)

Measuring wire rope means determining its outside diameter. The diameter is read across the rope, perpendicular to its length, at the widest cross-section. This dimension is what matters for fit with sheaves, drums, and fittings, and it’s the standard size used when selecting replacements. Use calipers or a micrometer to measure from outer edge to outer edge. If the rope is crushed or deformed, take the measurement at the widest visible cross-section to get the correct effective diameter. Measuring around the circumference would give a circumference value, which isn’t how rope size is specified, and measuring along the length wouldn’t provide a diameter. The widest-cross-section measurement avoids underestimating the size when the rope is slightly oval or worn, ensuring proper fit.