As you may already know, you don’t really need slings for your indoor climbing expeditions. It is when you move into the outdoor scene that they become an essential part of your kit. In a very basic sense, climbing slings are soft (not metal), sewn loops that are used to connect solid points like carabiners.
There are many, many other uses including building hauling systems, making a chest harness, as personal safeties, and so much more. The intended use of the sling will help determine the type and size you should buy. Luckily, slings are versatile and the same sling can be used in many different scenarios.
As mentioned above, slings are flat or tubular webbing that has been sewn into a loop. The webbing is either made from polyamide (nylon), or polyethylene (dynex, dyneema, spectra, aramid ect.). Both materials are very strong and lightweight but there are a few key differences between them.
Nylon, the slightly older and more classic of the two webbing materials is usually slightly wider and heavier than its counterpart. Nylon is not quite as static a material compared to dyneema and therefore has slightly more stretch to it. This can be beneficial in climbing scenarios where the nylon webbing can become shock loaded. The extra stretch helps to dissipate the overall force caused by a fall.
Dyneema webbing, on the other hand, is the new kid on the block. It is a stronger material compared to nylon and therefore can receive the same strength rating as a nylon sling while using less material. So dyneema slings tend to be thinner and lighter than conventional nylon slings. The weight savings alone make dyneema the go to option for many trad climbers and alpinists who froth over having the lightest rack possible. As dyneema is a new technology that is more involved to create, it is also a tad more expensive to buy. Another point to consider is that these webbings have a lower melting point than nylon, meaning that they are more susceptible to melting due to friction from say, a rope moving quickly over it.
All in all, either nylon or dyneema probably won’t make a big difference in your climbing. If you are counting grams and want the lightest, smallest rack possible, we would recommend you to go for dyneema. If on the other hand, you don’t mind some slightly wider webbing, and you don’t want to shell out the extra clams, then stick with nylon.
Slings tend to come in lengths of 30cm, 60cm, 120cm, 240cm, and even 480cm long. These dimensions are the measure of the sewn loop. So a 60cm sling is made from a 120cm piece of webbing that has had its ends sewn together. In general you will find the 60cm and 120cm slings to be the most common and widely used lengths. The 60s are great for “alpine quickdraws” and for extended gear placements that have wandered down a crack or off center from the climb. The 120s are also good for extended gear placements and are also the most common length for equalising sport anchors. A 240cm or 480cm sling can be handy when equalising trad anchors that may have three or more pieces and also for wrapping around a tree or rock when building anchors where other pro cannot be found. Depending on your setup you may only need one 120 sling. If you are trad climbing you will probably need four to six 60s, a few 120s and even a 240 or 480. Luckily slings are a relatively cheap part of your climbing kit and you can always add more as time goes on.
Proper climbing slings will be sewn together using a bar tack technique and will be rated to a minimum breaking strength of 22kN. Slings rated to be used for mountaineering and rock climbing will be most commonly denoted by a label at the seam reading “EN566” or another certification like a "UIAA”, which is sometimes found on the manufacturer's website instead. It is important to note however, that anytime you tie a knot into your webbing, you are decreasing the strength by, conservatively, 50%.
A word of warning! Although climbing slings are rated to a high strength of at least 22kN, they are very susceptible to wear and tear. It is important to always do a visual inspection of your slings before using them. Check them for abrasion, nicks, and tears. If they seem quite worn, torn, or abraded, it is time to retire them. Also, if their colour seems quite faded, then they have been damaged by the UV rays of the sun and may have reduced strength. Any sling that is very sun faded should be retired and replaced. Never climb on gear that does not pass a visual inspection. If in doubt, replace it.
I started highlining back in 2014 in and around Sydney. Since then I have highlined all around Australia. It has been excellent to see how the slackline scene has developed and grown since that time and I am excited to be apart of it. I am currently managing our CA Store in Collingwood so if you have questions regarding slacklining, highlining or climbing, come and say hello.