Crane Wire Rope: How to Choose It, Inspect It and Know When to Replace It

The wire rope is the part of a crane that wears out by design. Choosing the right rope and replacing it at the right time is the most important thing you can do for crane safety.

Choosing crane wire rope

• Follow the crane maker's rope specification first: diameter, construction, grade, lay and minimum breaking load.
• Multi-fall overhead cranes usually use a flexible 6x36 class rope with a steel core (IWRC), which resists crushing on the drum.
• Single-fall lifts and mobile or tower cranes with high lifts often need a rotation-resistant rope such as 17x7 or 18x7, so the load does not spin.
• Outdoor and port cranes benefit from galvanised rope.

See our guide to wire rope types and specifications for what each term means.

Inspection routine

• Daily / before use: a visual check by the operator for obvious damage: kinks, birdcaging, crushed sections, loose strands.
• Periodic: a thorough inspection by a competent person, at intervals set by the crane's use and local regulations, with records kept.
• Pay most attention to the sections that pass over sheaves, wind onto the drum, sit at the end fittings, or rest in the same spot when the crane is idle.

When to replace the rope

The international code of practice is ISO 4309, which gives detailed discard tables by rope type. As an example of typical limits, ASME B30.2 for overhead cranes calls for removal of running ropes when there are:

• 12 randomly distributed broken wires in one rope lay, or 4 broken wires in one strand in one lay
• A reduction in diameter of more than 5% of nominal
• Kinking, crushing, birdcaging or any distortion of the rope structure
• Core protrusion, heat damage or arc strikes
• Heavy corrosion or pitting

Rotation-resistant ropes have much stricter broken-wire limits, so check the rule for your rope type.

Measure diameter correctly

Measure across the crowns of opposite strands, at the widest point, with calipers that have wide jaws. Measuring across flats gives a falsely small reading.

Making crane rope last longer

• Keep it lubricated with a rope dressing that penetrates to the core.
• Check sheave grooves: a worn or undersized groove pinches the rope. See sheave sizing.
• Avoid shock loading and side pulling.
• Wind the rope onto the drum under tension so lower layers are not crushed.
• Store spare ropes off the ground, under cover.

We supply crane wire ropes with Mill Test Certificates, cut to length.