How do twists form in ropes?

The myth buster about twists in ropes – how they arise and how they can be avoided.

Twists are revolutions in ropes; loops that ‘spiral around’ as if by themselves when the rope is pulled through the hands, a carabiner, or belay device. Twists don’t reduce ropes’ strength but they do make them far harder to use. However, there are also accident mechanisms that are known to be caused by twists: When lowering, one hand is used to operate the belay device’s mechanism while the rope runs through the other hand, the braking hand. If a sturdy twist unexpectedly runs into the braking hand while lowering someone quickly, this will force open the fingers causing the braking rope to be lost. In the moment of shock, the contraction reflex can cause the belay device to be pulled too far. This means that twists in ropes are not only annoying but can also be dangerous. They should therefore always be avoided. But how can you do this and how do they arise in the first place?

Contrary to popular opinion, ropes don’t just become twisted of their own accord. Following production, climbing ropes are always neutral, smooth, and free from twists. In many cases, the first mistake that can cause twists in a rope occurs when the rope is removed from the packaging and used for the first time.

Twist cause 1 – Removing the rope from the packaging and using it for the first time:

Ropes are usually coiled, meaning that they are wound up and packaged as a coil. If you open the packaging and simply pull the rope straight out of the coil, a longitudinal twist forms in the rope for every revolution incorporated into it when coiled, resulting in the rope being completely twisted even though it has only just been removed from the packaging for the first time. When first opening classically wound rope coils, they therefore have to be unwound in exactly the same way as they were wound up. With a little practice and care, this is best done by placing the rope over the forearms and unwinding it. If there are two of you, you can also insert broom handles or smooth branches into the coil and use them to unwind the rope.

A growing number of manufacturers are supplying their ropes packaged ready for use, i.e. ‘ready to climb’. Such ropes can simply be placed on a rope bag, removed from the packaging and used to start climbing right away, free from twists. They should never be unwound in the same way as classically wound coils as the reverse effect would otherwise ensue and twists would be added to the rope. ‘Ready to climb’ ropes are usually indicated as such on the packaging.

Twist cause 2 – Redirecting the rope:

Twists can also form if a rope is pulled through top rope directional anchors or belay chains. If the carabiners or directional anchors through which the rope is pulled can rotate, the rope usually remains free of twists as the carabiner axes are perpendicularly aligned to the central axis of the rope. If, however, a rope is pulled through one or more directional anchors, the axes of which are not perpendicularly aligned to the central axis of the rope and that cannot realign themselves, different levels of friction are applied to the outside of the rope, which it compensates for by twisting. Twists that form in a rope while it is subjected to a load are far worse than those that arise when it is not, for example when removing the rope from its packaging. The load on the rope can cause the core and the sheath to twist against each other, firmly embedding the twists into the rope and making them extremely difficult to remove. Twists caused by directional anchors can be avoided by ensuring that either the directional anchors’ axes are perpendicularly aligned with the central axis of the rope or the directional anchors have as much play as possible and can realign themselves. The crossing of ropes on top rope directional anchors should also be avoided.

Twist cause 3 – The use of belay devices:

A similar effect occurs when a rope is pulled through a belay device, whether subjected to a load (lowering or rappelling) or not (belaying). The rope is once again redirected over various different radii and edges and its sides can be subjected to different levels of friction, which it compensates for by twisting. This effect is typical and can be clearly seen with classic methods such as belaying using a Munter hitch or a figure eight belay device. However, even tubes and modern semi-automatic belay devices or autotubes can sometimes cause ropes to twist depending on the carabiner geometry used.

Twist cause 4 – Picking up/storing the rope:

If a rope is picked up and wound into a coil as a ring after climbing, a similar effect ensues as when coiling a rope: a revolution is added to the rope for every loop that is picked up. The lap coil method where the rope is picked up alternately in loops twisted to the left and right has therefore proven effective. The left and right twists cancel one another out so the rope ultimately remains neutral. However, the ideal solution is always a rope bag as the rope can rest in this free from twists and tension while also being protected against environmental influences such as dirt or UV light

Why do some ropes twist more than others?

First of all, this question is worded wrongly – ropes don’t twist of their own accord. However, some ropes are more prone to becoming twisted than others. This is because they have a far lower sheath yarn tension, which in turn affects the rope’s rigidity. Ropes with a lower sheath yarn tension, i.e. softer ropes, can absorb twists better. However, this also often causes the core to twist within the sheath. Stiffer ropes with a higher sheath yarn tension are usually more cut and abrasion resistant but are not as able to absorb twists.