Toprope anchor with 11mm Dyneema sling...safe?

I am going to be setting up toprope anchors. I ordered 11mm sewn dyneema slings and want to know if they are safe to use as a top rope anchor.... I climbed 20 years ago when the runners were much wider this......thx!

A couple things to consider:
1) Dyneema slings are thin and (IMHO) tend to be a little less durable than nylon runners, so don't run them over sharp edges.
2) If you're anchoring on trees, please be thoughtful about how you wrap them since thin slings tend to damage the bark more than wider ones.
3) Dyneema doesn't stretch at all, so be sure you toprope on a dynamic rope.
4) Dyneema knots tend to get a little tight and are somewhat tougher to untie.

Otherwise you'll be fine as long as you stick to the age-old practices of building safe anchors; dyneema's a great new material. Enjoy!

The sewn dyneema runners are stronger than nylon however the material has a lower melting point. Avoid friction. Totally safe but expensive since nylon webbing is so cheap.

Yes, they are fine

Thank you for your replies!!!

I usually double or triple them up so the width is about equal to a nylon sling. YMMV.

Emmett Lyman wrote: 3) Dyneema doesn't stretch at all, so be sure you toprope on a dynamic rope.

I'm curious about your source for this...it seems like if the margin of error with static rope is so narrow that you have to use nylon webbing or else, then we shouldn't be using static line for toproping period. I know that nylon webbing has some stretch, but not a whole dynamic rose's worth.

Could you/someone else elaborate?

There is a dynamic rope in the system.

The anchor needs to be sound, but since there is a dynamic element in the system you get most of the energy absorbed through this (the rope).

A static top rope anchor may allow for less stretch and retraction thus keeping the anchor from having a sawing action over sharp edges. A top rope setup is usually going through many cycles of being loaded and unloaded.

Dyneema is very strong for the weight and size used in our applications.

Some interesting stuff here. I'm not a math guy, but the physics being discussed are way off.

Dyneema shouldn't be knotted or hitched (conventionally), as it is so static that it has lower melting points. It you do knot or hitch it, there are methods using a biner that will strengthen the knots. Carry slings made from nylon and dyneema, you'll have a more versatile kit.

If you use dyneema slings to extend a master point, two is best practice -- it's best practice with any material -- one sling has no redundancy.

Toproping (climbing at all) on a static line is treacherous, even with nylon webbing as anchor material. Good way to break your back. That said, consider investing in a static line, it's by far the simplest method of extending and equalizing anchor points. I prefer 120' of 10 mil, no need for cord or sling material (although a cord at one anchor point could simplify things a bit). The master point is easy with an over hand bight-on-a-bight. RE Optimistic: the [dynamic] climbing rope, be it a lead rope or gym rope (less stretch) will absorb any fall force. Static line has become the TR material of choice because of it's ease of use (fast equalization, easy to untie, static so it's less apt to saw (edges or nubbins of concern should still be protected)).

TRing off of bolts or one big honkin' tree is another beast. A cordelette is choice here (AMGA will tell you 7 mil nylon or 5 mil perlon, 6 mil nylon is plenty strong for me). Wrapped and tied with a figure eight master point around a tree, high enough to keep your rope from dragging sharply over an edge, or tied into a quad (self equalizing and redundant) for two bolts.

Good luck man..

You can tie knots in Dyneema/Spectra/etc. Know what the material's limitations are and try not to climb past them, so to speak.

Being redundant is good and highly recommend for certain situations/applications, but not with everything. Depending on what the environment and tools you have available will depend on the type of anchor built. Learn the rules to follow.

Using a dynamic rope to climb with on a Dyneema built anchor, depending on competency of builder, all will be fine.

There are plenty of posts, books, or instruction you can follow and learn by.

Yes, you should know the limitations of the tools you use. Not looking to debate, but..

Again, generally dyneema shouldn't be knotted. Every manufacturer recommends against this practice as it's strength can be reduced by 50%. For me, that's unacceptable in any anchor application, multipitch or TR. Dyneema also has a very low coefficient of friction. That's why dyneema knots always seem welded and why it's difficult to use in friction hitches, another application that's discouraged. I've melted dyneema prusiks with very little load.

http://dmmclimbing.com/knowledge/knotting-dyneema-vid/

good discussion here:

mountainproject.com/v/conse…

If you must knot dyneema, there are a few particular knots where passing a caribiner through a bend will increase the knot's breaking strength.

Knotting dyneema is absolutely and utterly fine as long as you have rope in the system and take some basic precautions and understand the limitatiobs

Even guides do it all the time ..

Theres a lot of misconceptions with dyneema out there

;)

bearbreeder wrote: Theres a lot of misconceptions with dyneema out there ;)

Yes, there are. And that knotting it is a good practice is one of them.

chris magness wrote: Yes, there are. And that knotting it is a good practice is one of them.

Talk to the AMGA

youtube.com/watch?v=2mSZ5RO…

;)

Given that most dyneema/spectra slings are rated at 22kn, even cutting their strength in half (by knotting them), means they're still nearly 2500lbs strong. plenty strong for toprope situations.

just to clarify, if you are knotting dyneema, as in joining an UNSEWN sling together, use a triple fishermans....

but i think most folks here are talking about putting a knot in a sewn sling to make it redundant.

Edelrid makes some cool slings that have a dyneema core and nylon sheath, but it's still flat webbing--best of both worlds.

and yes, spectra/dyneema stretches so little, it's effectively static...like a steel cable.

knotting dyneema is fine--as long as you know its limitations and when you might want to avoid the practice. most prudent folks use a nylon or nylon/spectra combo, runner for their rappel extensions....but any time you have rope in the system, dyneema is fine--the dynamic properties of the rope ameliorate the weaknesses (static and low melting point) of the dyneema.

beware the folks on here with absolutes...and listen to the folks with a bit more experience: bearbreeder, jim titt, rgold, etc.......

If the sling is not touching ANY rock, trees or edges then its all good. If you have the opportunity for abrasion across rock, trees or edges then there are risks.

If you are just doing a few laps you should be fine. But do not underestimate the amount of wear repetitive top roping can cause. 11mm slings have very little meat available for wear. Personally I'd be using 1" webbing or cordalette at a minimum.

For top ropes that see lots of laps I use retired rope, preferably static but dynamic is fine.

chris magness wrote:Dyneema shouldn't be knotted or hitched (conventionally), as it is so static that it has lower melting points..

Chris, I think you mistyped here. Dyneema does not have a lower melting point because it is "so static". It has a lower melting point because of material properties. Steel cable is more static than Dyneema but has a higher melting point, wouldn't you agree?

chris magness wrote:http://dmmclimbing.com/knowledge/knotting-dyneema-vid/

That first link you posted discusses the fact that Dyneema is not sold in bulk and you should not tie your own slings out of Dyneema webbing. I agree.

However, I think most other people in this thread are discussing knotting pre-sewn Dyneema slings in applications like creating a masterpoint or tying a magix X. Different animal and something that is done all the time - as long as one understands the limitations. See the AMGA link beerbreader posted.

You're arguing with bearbreader, but much of the second link you posted and called a "good discussion" actually supports his position. Odd.

Optimistic wrote:I'm curious about your source for this

Right, you caught me... it's hyperbole to say it doesn't stretch at all. But it doesn't stretch much, and you shouldn't expect it. "Think of a dyneema sling more like a carabiner and nylon sling more like a climbing rope." That's from Chris McNamara, so I trust he knows his stuff.

Optimistic wrote:then we shouldn't be using static line for toproping period.

Yeah, sure, why not. Static rope works for TR with a good belay, but why bother? Even a short drop due to slack in the system can be painful. Just use a dynamic rope. That said, even static rope has a bit of stretch, so hopefully no one's breaking backs.