Dynamic rope

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Internal structure of 10.7mm dynamic kernmantle climbing rope Kernmantle climbing rope dynamic Sterling 10.7mm sheath opened.jpg
Internal structure of 10.7mm dynamic kernmantle climbing rope

A dynamic rope is a specially constructed, somewhat elastic rope used primarily in rock climbing, ice climbing, and mountaineering. This elasticity, or stretch, is the property that makes the rope dynamic—in contrast to a static rope that has only slight elongation under load. Greater elasticity allows a dynamic rope to more slowly absorb the energy of a sudden load, such from arresting a climber's fall, by reducing the peak force on the rope and thus the probability of the rope's catastrophic failure. A kernmantle rope is the most common type of dynamic rope now used. Since 1945, nylon has, because of its superior durability and strength, replaced all natural materials in climbing rope.


Rope types

Dynamic climbing ropes are classified into three categories: Single ropes, twin ropes, and half ropes (also referred to as 'double ropes').

Both twin and half ropes have the advantage of redundancy, as well as allowing a rappel along the full length of the climbing rope (by tying both ropes together), so that climbers can descend from a long multipitch route with fewer rappels than with a single rope. Some ropes are 'triple rated', meeting the standards for all three rope types, so they can be used in each configuration.

Length and diameters

Dynamic ropes used for rock climbing come in a variety of lengths and diameters, with the most common lengths being 50 metres (164.0 ft), 60 metres (200 ft), 70 metres (230 ft). Lengths will vary depending on rope maintenance and age, and there are even ropes as long as 80 meters for specialized ascents on routes that would normally require a multi-pitch climbing attempt due to being only slightly longer than a standard rope length.

Rope diameters are generally between 8.3mm and 11.5mm, with the different diameters used for slightly different purposes. Sport and multi-pitch trad climbers often value thinner ropes because they are lighter, and have less rope drag. Thinner ropes also run more smoothly through belay devices, especially assisted braking devices or 'tube-style' devices operated in 'guide mode', which can be tedious to pull thicker or stiffer rope through. Lighter, thinner ropes, however, have less strength than a thicker rope and will sustain fewer hard falls. Note that some belay devices are better suited for different rope diameters. This is particularly relevant with assisted braking devices, such as the Petzl Grigri (which, for example, works best with a 9.4-10.3 mm thick line [1] ) or the Faders SUM. Users must make sure to read the instructions for the device carefully to ensure safety and recognize any limitations to rope diameter.

Standards and testing

All modern rock climbing dynamic ropes rated by the UIAA must meet certain standards and pass testing for Construction, Sheath Slippage, Static Elongation, Impact Force on first fall, and Number of falls held. [2] The force rating indicates the maximum amount of force the rope can deliver to a falling climber, measured in kilonewtons (kN), under test conditions designed to simulate a hard fall; typical climbing ropes range from 9kN up to an Arborist's 24kN. The force rating is often misunderstood by climbers, because all other climbing gear is rated by the breaking strength (in kN) of the material. Whereas a higher rating (indicating greater strength) is desired for other gear, for dynamic ropes a lower rating is generally desired, as this indicates it would give a 'soft catch' that is less likely to injure the climber or break or dislodge protection or anchors. [3]

Unlike most climbing equipment, dynamic ropes do not have a rated tensile breaking strength. Instead, the strength of a rope is tested by the number of standard test falls a rope can sustain before breaking. The test falls use an 80 kg weight for single ropes (55 kg for half ropes), and a fall factor of 1.7 (4 meter fall on 2.3 meters of rope). This tests simulates a very hard fall that would rarely occur. When climbing, it is possible to produce a fall factor as high as 2, however, real-world climbing situations include additional shock absorbing elements which are not included in the test standard, such as the body of both the climber and belayer, elasticity of their harnesses and anchor materials, and friction between the rope and the belay device, and any protection pieces. [2] [4] Single ropes must sustain at least 5 such falls before breaking, and a rope that can sustain more than 9 falls is considered a 'multifall' rope. [4] In practice, climbing ropes rarely if ever break due to a fall alone- all documented rope failures involve the rope being cut or damaged, for example by abrasion against a sharp rock edge. [2] Ropes are especially vulnerable to being cut while they are weighted with the body of the climber, and moving over a sharp edge (for example if a following climber is resting his weight on the rope, or using the rope for assistance, while swinging or traversing under a roof, while being belayed from above). In general, thicker ropes will be stronger and more durable, and have a higher fall rating.

Rope care and maintenance

Modern ropes are made from nylon and don't require a great deal of maintenance. Ropes that are frequently used are often inspected for cuts, abrasions, or frayed areas; any cut or fraying that passes into the core of the rope is cause for concern. Ropes can also be washed to clean them of any extensive dirt or grime. Ropes must also be kept away from chemicals or seawater which may damage them, or stored for long periods in direct sunlight which can cause UV damage over time. [5]

Every fall lessens the amount of impact a rope can later absorb, and hard falls can seriously compromise the strength of a rope, without showing obvious signs of wear. One definition of a 'hard fall' is a long fall (> 10–15 meters) with a fall factor greater than one. Manufacturers often recommended that ropes be retired if they sustain an extremely hard fall, even if they do not show outward signs of wear. [2] [4] [6]

See also

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Figure-eight loop

Figure-eight loop is a type of knot created by a loop on the bight. It is used in climbing and caving

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Climbing protection is any of a variety of devices employed to reduce risk and protect others while climbing rock and ice. It includes such items as nylon webbing and metal nuts, cams, bolts, and pitons.

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Glossary of climbing terms List of definitions of terms and concepts related to rock climbing and mountaineering

This glossary of climbing terms is a list of definitions of terms and jargon related to rock climbing and mountaineering. The specific terms used can vary considerably between different English-speaking countries; many of the phrases described here are particular to the United States and the United Kingdom.

Ice climbing Activity of ascending ice formations

Ice climbing is the activity of ascending inclined ice formations. Usually, ice climbing refers to roped and protected climbing of features such as icefalls, frozen waterfalls, and cliffs and rock slabs covered with ice refrozen from flows of water.

Rock-climbing equipment

A wide range of equipment is used during rock or any other type of climbing that includes equipment commonly used to protect a climber against the consequences of a fall.

Free climbing Form of climbing not using aid climbing

Free climbing is a form of rock climbing in which the climber may use climbing equipment such as ropes and other means of climbing protection, but only to protect against injury during falls and not to assist progress. The climber makes progress by using physical ability to move over the rock via handholds and footholds. Free climbing more specifically may include traditional climbing, sport climbing, bouldering and most forms of solo climbing. Free climbing a multi-pitch route means free-climbing each of its pitches in a single session. At the end of each pitch, climbers anchor themselves to belay stations where they can rest.

Aid climbing Style of climbing

Aid climbing is a style of climbing in which standing on or pulling oneself up via devices attached to fixed or placed protection is used to make upward progress.

Sport climbing Form of rock climbing

Sport climbing, is a form of rock climbing that relies on permanent anchors, permanently fixed into the rock for climber protection, in which a rope that is attached to the climber is clipped into the anchors to arrest a fall; it can also involve climbing short distances with a crash pad underneath as protection. This is in contrast to traditional climbing where climbers must place removable protection as they climb. Sport climbing usually involves lead climbing and toproping techniques, but free solo and deep-water solo climbing on sport routes is also sometimes possible.

Belaying Rock climbing safety technique using ropes

Belaying is a variety of techniques climbers use to create friction within a climbing system, particularly on a climbing rope, so that a falling climber does not fall very far. A climbing partner typically applies tension at the other end of the rope whenever the climber is not moving, and removes the tension from the rope whenever the climber needs more rope to continue climbing.

Lead climbing Competitive discipline of sport climbing

Lead climbing is a climbing style, predominantly used in rock climbing. In a roped party one climber has to take the lead while the other climbers follow. The lead climber wears a harness attached to a climbing rope, which in turn is connected to the other climbers below the lead climber. While ascending the route, the lead climber periodically connects the rope to protection equipment for safety in the event of a fall. This protection can consist of permanent bolts, to which the climber clips quickdraws, or removable protection such as nuts and cams. One of the climbers below the lead climber acts as a belayer. The belayer gives out rope while the lead climber ascends and also stops the rope when the lead climber falls or wants to rest.

Rock climbing Sport in which participants climb natural rock formations

Rock climbing is a sport in which participants climb up, down or across natural rock formations or artificial rock walls. The goal is to reach the summit of a formation or the endpoint of a usually pre-defined route without falling. Rock climbing is a physically and mentally demanding sport, one that often tests a climber's strength, endurance, agility and balance along with mental control. Knowledge of proper climbing techniques and the use of specialized climbing equipment is crucial for the safe completion of routes.

Kernmantle rope is rope constructed with its interior core protected by a woven exterior sheath designed to optimize strength, durability, and flexibility. The core fibers provide the tensile strength of the rope, while the sheath protects the core from abrasion during use.

Ascender (climbing) Devices used for ascending, braking, or protection in climbing

An ascender is a device used for directly ascending a rope, or for facilitating protection with a fixed rope when climbing on very steep mountain terrain.

Prusik knot

A Prusik is a friction hitch or knot used to attach a loop of cord around a rope, applied in climbing, canyoneering, mountaineering, caving, rope rescue, ziplining, and by arborists. The term Prusik is a name for both the loops of cord used to tie the hitch and the hitch itself, and the verb is "to prusik". More casually, the term is used for any friction hitch or device that can grab a rope. Due to the pronunciation, the word is often misspelled Prussik, Prussick, or Prussic.

In rock climbing, an anchor can be any device or method for attaching a climber, a rope, or a load above or onto a climbing surface—typically rock, ice, steep dirt, or a building—either permanently or temporarily. The intention of an anchor is case-specific but is usually for fall protection, primarily fall arrest and fall restraint. Climbing anchors are also used for hoisting, holding static loads, or redirecting a rope.

Reverso (climbing equipment)

A Reverso is a belay device developed and patented by Petzl, used for example in rock-climbing and other activities which involves rope-work. Another version of this device is the Reversino, intended for use with thinner ropes.

Climbing rope Rope used to secure climbers

A climbing rope is a rope that is used in climbing. It is a critical part of an extensive chain of protective equipment used by climbers to help prevent potentially fatal fall-related accidents.

Belay device Mechanical piece of climbing equipment

A belay device is a mechanical piece of climbing equipment used to control a rope during belaying. It is designed to improve belay safety for the climber by allowing the belayer to manage their duties with minimal physical effort. With the right belay device, a small, weak climber can easily arrest the fall of a much heavier partner. Belay devices act as a friction brake, so that when a climber falls with any slack in the rope, the fall is brought to a stop.


  1. "Sport - Petzl USA".
  2. 1 2 3 4 Sterling Rope Guide to Rope Engineering, Design, and Use Archived 2013-08-10 at the Wayback Machine
  3. Alpine Exposures FAQ- Climbing Ropes explained
  4. 1 2 3 Mammut: Standards for dynamic ropes
  5. "Rope care – Looking after your rope". Access Ropes. Retrieved 2021-10-21.
  6. Mammut Rope Care Manual