The attached drawing illustrates the correct way to measure wire ropes by measuring their:

• A. Diameter
• B. Length
• C. Tension
• D. Pitch

Answer: (A)

Measuring the rope by its outer diameter is how you determine its size and rating. The strength, compatibility with sheaves, hooks, and rigging hardware, and the load charts are all based on the rope’s nominal diameter, which is read across the rope’s widest point perpendicular to its length. The length simply tells you how long the rope is and doesn’t reflect its capacity. Tension is a condition you apply during use or testing, not a measurement of the rope’s size. Pitch refers to spacing along a rope’s turns and isn’t used to size or rate a wire rope.

So, the correct approach shown is to measure the rope’s diameter with a caliper or diameter gauge at several straight, non-deformed sections and use the average. This matches how rope size is defined and how its load rating is determined.