What starts off as a simple choice quickly becomes horribly confusing.
I think it’s to do with all the “pros and cons” that get weighed up in the whole Dyneema vs nylon debate. They quickly obscure the differences between the two which are actually impactful.
It starts with the thought, “Hey, Dyneema looks cool. I can’t believe how thin it is. It must be really strong.”
…And then you hear about how it can’t be knotted, and that it even melts when a knot in it is loaded.
Before long, you’re looking at tables from scientific sources comparing the properties of each material, frantically worrying about whether there’s some fatal drawback of those suspiciously thin Dyneema slings you’ve been eyeing.
Really though, the choice is actually pretty simple.
It only gets complicated when the the information is taken way, way out of context.
For example, Dyneema is 15 times stronger than steel.
“That means that Dyneema slings will be much stronger than nylon ones, right?”
They’re still rated at 22kN, just like nylon ones are. That’s because Dyneema slings are significantly thinner than nylon ones.
“Why not have thicker Dyneema slings then?” I hear you ask.
The reason is that it’d be utterly pointless. You don’t need more than a sling rated at more than 22kN. It’s already overkill for the sake of safety, which is fine and all, but after a certain point “I just want to make extra sure” becomes paranoia.
So, take off your safety goggles and hang up your hard hat, my paranoid friend. I’m going to show you how easy it is to decide between Dyneema slings and nylon slings.
Yes, even if safety is your only concern.
How to Decide Between Nylon and Dyneema
It’s simple. I’m going to ask you a series of questions, and at some point you’ll know your answer.
I’ll start with the biggest deciding factors.
Are you climbing in wet / cold / wintery conditions?
Absolutely go with Dyneema.
In the cold recesses of the Earth, you’ll find the rare, almost mythical breeds of climbers known as “alpine climbers” and “ice climbers” appear to gather and roost.
For these strange creatures, who know neither the light of the sun nor the warmth of civilization, nylon has no place.
Because nylon slings will freeze solid.
You see, Dyneema is far more water resistant than nylon.
In terms of strength, it’s always the better choice if your slings are going to be getting some kind of water exposure. Nylon experiences a 15% loss in strength when it’s wet, and that stacks on top of the already added weakness that tying knots in it introduces.
When I say “water exposure,” I’m not just talking about waterfalls in the canyons and other such places that people like to climb near. I’m talking about something as simple as rain.
Sure, most climbers don’t like climbing in the rain. If you’re one of those people, then this isn’t going to be the deciding factor, so go ahead and read on.
Even if you do climb in wet conditions, there are some more things for you to consider before deciding to go with Dyneema. If you’re climbing in freezing cold conditions, however, then Dyneema is easily the best choice, and you’re just going to have to keep its drawbacks in mind while you use it.
The next question highlights exactly what I’m talking about.
Want to be able to tie knots with it?
Nylon is your only choice.
Like I said before, Dyneema melts when loaded with a knot in it.
Strangely enough, it’s for the same reason as to why tying knots with it wouldn’t work even if it didn’t melt.
And that reason, is knot slippage.
Simply put, Dyneema is so frictionless, that knots will just slide loose.
Because of all that movement that’s brushing against itself when a knotted piece of Dyneema is loaded, it generates enough heat to actually melt through.
This is why you never see Dyneema webbing. It’d be useless.
If you don’t know what webbing is, it’s just a roll of “un-sewn sling material” that you knot together at whatever length you like to create your own custom slings. If you’re interested in that, then take a look at this guide I wrote about nylon webbing and which kind is the best.
For now, let’s move on. Let’s say you’re not too interested in tying knots in your slings and you’re still undecided. Well, take a look at this next point:
Want the most cut / abrasion resistant ones possible?
Go with Dyneema. It’s by far the most cut resistant and abrasion resistant of the two.
In fact, it’s often used to make cut-resistant gloves. That’s how good it is.
Since slings are often used to extend gear, it’s quite possible that you’ll encounter a sharp ledge near your anchor that you’d rather have a sling running over instead of your rope.
This most often happens when setting up a top rope anchor. The trees and rocks that you’ll be tying slings to will be above the ledge for the most part. That’s where the cut resistance and abrasion resistance of your slings will truly shine.
That’s not to say that only top ropers will benefit from Dyneema slings. Canyoneers will especially appreciate that extra abrasion resistance with all that sand around.
Any climber who’s been in that environment knows: soft gear and sand don’t mix.
Sand can practically saw through soft gear when there’s too much movement. It’s like sandpaper, but… well… without the paper.
If you’re going to be climbing in sandy environments, then save yourself the anxiety and go with Dyneema.
However, if you’re climbing in normal, temperate environments like most sane climbers do, then abrasion isn’t really going to a be problem for you. After all, if nylon wasn’t up to scratch when it comes to dealing with the levels of abrasion encountered in normal climbing environments, then it wouldn’t be used by climbers at all!
So, keep reading on if you’re still unsure which one to go for.
Want the cheapest ones possible?
Well, that’s easy. Nylon is basically always cheaper.
On average, Dyneema slings will cost about a third more.
However, slings aren’t particularly expensive compared to other pieces of your climbing arsenal. Your absolute total savings from going with nylon aren’t going to be that impressive.
Even so, I guess you could say that the cost adds up over time if you’re buying many slings and leaving them behind semi-regularly. If the cost of that bothers you, then go with nylon to save yourself a bit of extra dough.
Finally, let’s take a look at the last important difference between Dyneema slings and nylon slings:
Want the slimmest, lightest ones possible?
Dyneema wins every time.
Have you seen how ridiculously thin they are?
It’s funny. Some climbers actually choose to go with nylon slings simply because Dyneema ones are scary if you’re unfamiliar with them.
If you want a priceless reaction, hold one up in front of your non-climber friends and tell them: “This… is what saves my life if I fall.”
At first, they’ll think you’re joking. Then they’ll think you’re crazy. Even after explaining how it’s 15 times stronger than steel, they’ll still feel like you’re pulling their leg.
It just doesn’t look strong. That’s why it’s so off-putting to a lot of climbers. Their intellect says “yes,” while their gut feeling says “no.”
However, other than making you feel like a daredevil, its slim profile does have a couple benefits that are actually useful.
First of all, it makes it lighter than a nylon sling. To be honest though, slings are so light as they are already, so I’m just going to gloss over this point. The difference doesn’t really add up to much at all. It makes even less of a difference than the cheaper price of nylon slings, which I was talking about before.
However, the slim profile of Dyneema slings make them fantastically compact on your gear rack. They really take up no space at all.
Trad climbers especially are going to really benefit from switching to Dyneema slings, with all the gear that they’re already lugging around.
Really, the only drawback to Dyneema slings is that you can’t tie knots in them without compromising their safety.
All that means is that you’ll have to slightly change the way you create anchors.
Or, I guess, you could just go with nylon if that’s something which bothers you.
For everyone else – even beginners – I’d recommend going with Dyneema slings. You can check out this post here if you want to know which Dyneema slings are the best.