Choosing the Right Rope

With each application, your choices of wire ropes can be many. How do you know which one will work best for you? All wire ropes have a combination of characteristics that give them specific performance abilities. Before you choose, it pays to match the requirements of an application with the characteristics of the rope.

 In the operating ropes of large surface mining equipment, not all characteristics have equal importance. Two characteristics - resistance to metal loss and deformation and fatigue resistance - are usually the main considerations. Most applications require a balance of these two characteristics. The strength of the ropes can also be important, of course, when considering a different rope construction.

Fatigue Resistance

Fatigue resistance involves metal fatigue of the wires that make up a wire rope. Fatigue is normal and will occur in areas of the rope that:

• Repeatedly bend over sheaves and drums
• Dampen vibrations (near end attachments or other points of rope restriction)
• Are subjected to changes in load

In general, a rope made of many wires will have greater fatigue resistance than rope made of fewer, larger wires because smaller wires have greater ability to bend as the rope passes over sheaves or around drums. Lang lay ropes are more fatigue-resistant than regular lay ropes. Flex-X and TUF-KOTE/PFV ropes are also more fatigue resistant than standard ropes.

Every rope is subject to metal fatigue from bending stress while in operation, and therefore the rope’s strength gradually diminishes as the rope is used.