Crane Rope Selection: Tower Cranes, Hoists and Winch Drums

The crane rope is the most critical and most heavily worn component of lifting equipment. The wrong choice both shortens its life and puts workplace safety at risk. Here is what to consider.

1. Start with the rope in the equipment catalogue

The crane manufacturer specifies the diameter, construction, tensile grade and lay direction. When choosing an equivalent rope, you must not go below these values. Measuring the current rope’s diameter correctly is the first step.

2. Construction

• 6x36 WS + IWRC: Balance of flexibility and abrasion resistance; common on cranes that run frequently over sheaves.
• 6x19: Less flexible, more abrasion resistant; simpler lifting applications.
• 18x7 / 35x7 (rotation resistant): Prevents load rotation on tower and mobile cranes making high lifts on a single fall.

3. Lay direction and type

Right/left lay and regular (ordinary) or Lang lay are chosen according to the drum and sheave arrangement. The wrong lay direction can cause the rope to unlay and wear quickly.

4. Sheave and drum diameter

As the sheave-to-rope diameter ratio decreases, the wires bend more and fatigue breaks start early. Follow the manufacturer’s recommendation and check groove dimensions.

5. Safety and replacement

The working load is found by dividing the minimum breaking load by the safety factor (breaking load calculation). When broken wires, diameter loss, crushing or corrosion are seen, the rope must be assessed according to ISO 4309 and replaced if necessary.

For lubricated crane rope, send us the details of your current rope; we will identify the equivalent and cut it to size. Use only certified rope and fittings for lifting applications.