How and what to compare to choose the rope for you!

The other day I noticed one of our competitors advertising their brand as the best ropes on the planet and I found myself asking – who can tell ? The recent string of opinions on ClimbZA certainly demonstrated that there are plenty of opinions out there but very little concrete fact. Sure, most experienced climbers have had the opportunity over the years to climb on different brands and we all formulate our own preferences based on handle and durability.  But are there really any facts that can help one choose between the various options?

The truth is that while durability & handle are often the issues that climbers use to judge a rope; there is a much more important issue at stake – safety. It might be stating the obvious, but a climbing rope’s primary function is to catch a falling climber safely. What is not so obvious are the factors which contribute to a safe catch. It’s more than ensuring that the rope is strong enough. Most modern ropes are strong enough to pick up a small bakkie but that does not ensure that the protection which links the rope to the rock will not be strained to breaking point or that the fallen climber doesn’t get carried away with a broken back due to shock loading.

Impact Force: The most important factor is called impact force which can be defined as the amount of force generated during a fall which a rope is unable to absorb and will therefore be transmitted to the rest of the system; the pro,  the belayer’s device, his harness and hand, the climber’s harness & most importantly the climber’s body. Take a fall on a steel cable and you will spend a while in hospital contemplating the foolish act. A cable has no ability to absorb impact and therefore the total force is absorbed by the climber’s harness & body.

Climbing ropes are designed to be dynamic to absorb the force & only transmit a limited amount to the rest of the system. The more force that is transferred to the rest of the system, the greater the chance that something will go wrong. Put another way, when climbing an R-rated trad. route, you stand a much better chance that your gear will stay in place on a rope with a very low impact force. In much the same way, when you have a nervous novice belaying you, the less shock that your fall exerts upon them, the more likely they will hold your fall properly.

Limited Stretch : On the other hand, one does not want to climb on an bungee cord which will stretch so much that you are in danger of hitting the ground and then being whipped back up to hit your head on the roof from which you fell. The standard for dynamic ropes stipulates both a maximum impact force and a maximum amount of stretch –

Within climbing manufacturing circles, it is commonly acknowledged that this balance between achieving a low impact force, while maintaining limited stretch, is a very difficult thing to achieve. The current standards require a maximum elongation of 40% at the first drop, and only at the first drop. This is reasonably easy to achieve, however it is much more difficult to limit the stretch that occurs in future falls.

Fall rating: The next important issue is to ensure that the rope is able to hold numerous falls at close to maximum force. It’s fairly logical to assume that once a rope has taken one serious fall, it may not be capable of holding another such fall. The most serious fall is when a climber falls straight past his belayer and is caught directly by the belayer without any intermediate runners. This is known as a factor 2 fall (distance of fall/length of rope between leader & belayer = 2). The current CE norm (Standard EN 892) requires that a single rope must withstand 5 successive factor 1.77 (UIAA) falls with a mass of 80kg (double rope 5 successive falls with a mass of 55kg).  (Note: This is a pretty serious fall; most sport falls don’t even come close to a factor 1 – check out www.bealplanet.com for more info).

The number of falls shown on the technical notice must not be higher than the poorest result found by the certifying laboratory. In order to calculate that performance of a specific model of rope, a rope is supplied for testing to an independent testing lab.  Three dynamic tests are carried out on 3 samples of the rope by having an 80kg body dropped in such a way as to simulate a factor 1.77 fall. After a measured recovery time, the body is dropped on the same piece of rope again. This process is repeated over and over until the rope snaps. The testers then move onto the next section of the rope. At the end of the process, the lab publishes the number of falls held which must not exceed the poorest result measured by the testing lab on the 3 samples and it must be the number of falls guaranteed by the manufacturer. This result is feature on the rope documentation & provides another measure that can be used to compare ropes. Obviously the more falls that a rope is able to take, the more durable the rope will be. On the other hand, in order for a rope to hold more falls it generally has to get thicker and therefore heavier. (visit https://www.youtube.com/user/BEALofficial for videos of testing procedures)

Quality Management: This begs the question – how does one know that the next batch of ropes will perform in the same manner that the ones in the first batch? In order to achieve consistent quality results all rope manufacturers are required to run a quality management system; most commonly ISO 9001. This system monitors both the consistency of the manufacturing process as well as the quality of the end result. In other words, the process is checked to see that the same result can be achieved each time a rope is produced.

An understanding of the above factors enables the consumer to be much more objective about his/ her choice of rope. All the above mentioned statistics are listed by all reputable manufacturers on the packaging of their ropes so it’s easy to do comparisons.