Sewn Nylon for Alpine Draws?

So I decided to read through the latest version of Long's anchors book. One thing that I found interesting was that he came out heavily in favor of nylon over dyneema slings. His rationale was that although dyneema has a higher breaking strength, it is super static, and the shock absorbing qualities of comparably stretchy nylon allow it to handle greater shock loads.

This got me wondering whether nylon would fair better than dyneema for alpine quickdraws. I'm less concerned about slings breaking (I don't recall ever hearing of this happen on a leader fall) than I am about pieces pulling. In the event of a leader fall, would an additional dynamic component in the system absorb additional force, thereby reducing the load on the protection and making it less likely for gear to fail and/or pull?

I'm not old-school enough to fashion a set of draws using tubular webbing hand-tied into loops, but they do make sewn nylon slings...of course, dyneema slings are nice and thin which makes racking a bunch of them easier, but if nylon truly is safer...

Nylon vs dyneema runners will not change the impact force on a piece during a lead fall. The dynamic part of the system is the rope, not the quick draws. People chose nylon vs dyneema for numerous reasons, however dyneema is generally preferred because it is less bulky, and it does not absorb water to the same degree that nylon does. Saturated nylon is significantly weakened. Some chose nylon for alpine draws because nylon is more durable than dynemma, however as mentioned, generally alpine draws are dynemma.

Sometimes nice to have one of your double lengths be a tied nylon sling so you can untie it and bail off it. Nylon v. Dynema has been heavily debated on the forums. If your gear is that marginal you have bigger fish to fry hahah

Ted Pinson wrote:So I decided to read through the latest version of Long's anchors book. One thing that I found interesting was that he came out heavily in favor of nylon over dyneema slings. His rationale was that although dyneema has a higher breaking strength, it is super static, and the shock absorbing qualities of comparably stretchy nylon allow it to handle greater shock loads. This got me wondering whether nylon would fair better than dyneema for alpine quickdraws. I'm less concerned about slings breaking (I don't recall ever hearing of this happen on a leader fall) than I am about pieces pulling. In the event of a leader fall, would an additional dynamic component in the system absorb additional force, thereby reducing the load on the protection and making it less likely for gear to fail and/or pull? I'm not old-school enough to fashion a set of draws using tubular webbing hand-tied into loops, but they do make sewn nylon slings...of course, dyneema slings are nice and thin which makes racking a bunch of them easier, but if nylon truly is safer...

I could be wrong but I think that Long's focus was on the connection between the belayer and the belay anchor in the event of a fairly short factor 2 fall. Very little rope out, first piece not in yet kind of thing. But maybe what you're discussing here, essentially thinking of the sling as a shock absorber for a running protection point (as opposed to the belay anchor) hasn't even really been studied. My guess is that with a lower fall factor the rope will swamp any contribution that a runner could make...but there's a reason science isn't based on "my guess" and indeed Long's data on the nylon versus dyneema was pretty impressive.

He's on Supertopo, why not ask him? I believe Largo is his username.

A larger factor for me is the durability of thin dyneema slings. They have a 2-3 year lifespan (max) and need to be replaced more often at a significant premium. Sure they rack a bit cleaner and are lighter, but my sling size isn't a factor in my performance. I've gone back to 9/16 nylon for my alpine draws.

Additional advantages; You can knot them (better/stonger than dyneema), cut them and retie for rap anchors, use them for a rappel back up (kleimheist), less painful ($$$) to replace.

Haha...couldn't hurt. Yeah, he definitely argues against using dyneema or other static material for tethers (e.g: Daisy Chain) for that reason (FF2), but he also argues against dyneema much more generally as well:

"Recent testing strongly suggests that old-style nylon sling material (and cordage) is superior for general use in rock climbing. The mega-strong "tech webbings" were originally produced...for static loads...Since climbing' roped safety system acts as a peak (dynamic) force load limiter, nylon with just a little bit of stretch helps to absorb peak forces, while the virtually static tech webbing translates dynamic forces directly to the carabiners and protection devices, which can blow apart under high-impact dynamic loading. Moreover, recent tests from several sources indicate that nylon webbing and cordage can absorb (without breaking) greater dynamic forces than high-tensile strength cord and spectra or Dyneema webbing." (Long, 81).

This, to me, suggests that using nylon slings for quickdraws would put less force on gear by acting as peak force limiters.

Jason Todd wrote:A larger factor for me is the durability of thin dyneema slings. They have a 2-3 year lifespan (max) and need to be replaced more often at a significant premium. Sure they rack a bit cleaner and are lighter, but my sling size isn't a factor in my performance. I've gone back to 9/16 nylon for my alpine draws. Additional advantages; You can knot them (better/stonger than dyneema), cut them and retie for rap anchors, use them for a rappel back up (kleimheist), less painful ($$$) to replace.

Is this 2-3 yr lifespan generally accepted or just your rule? I have dyneema slings I use that are older than that. Hope I don't need to toss them.

Jake wander wrote: Is this 2-3 yr lifespan generally accepted or just your rule? I have dyneema slings I use that are older than that. Hope I don't need to toss them.

Joe Healy did pull tests over the course of a few years with dyneema slings and found they lost 3-4kn of strength per year. At that rate it wouldn't take long to make a sling originally rated at 22kn substantially weaker. While I understand this is a single test it certainly caused me to look closer into dyneema. The results make sense given dyneema has very rigid and low stretch properties. Multiple cycles of bending (general use) will eventually break the individual fibers much quicker than nylon.

My own dyneema slings fuzzed up pretty quickly further reducing my confidence. It's ultralight gear and really should be considered a "consumable" item.

And John Sherman breaking a girth hitched sling and DMM's videos of them breaking really doesn't inspire long term confidence in them for ME.

Of course it is difficult to gauge amount of use for an individual user. Older slings are probably not the weakest link in a system and the likelihood of breakage is low. BUT, mitigation of risk is important to me and this was a pretty easy decision to go back to nylon. Dyneema is probably one of those areas where manufacturers replacement intervals should be heeded.

About the time jhealy posted his sling testing conclusions, I had a few old Dyneema slings pull tested. There was a difference: Joe climbs a lot more than I do, and his gear sees more use. The slings I tested were in the 5-10 year old range and had seen relatively LITTLE use. And they tested out much higher than Joe's, losing something closer to 1 kN per year (no, I didn't test enough to get this precise; I'm only saying my slings were much stronger than Joe's results would suggest). So I concluded that USE rather than age was the principle factor. This was confirmed by an article that came out of BD's test lab that found that abrasion and UV exposure were responsible for sling degradation; age by itself wasn't significantly responsible for strength loss.

Back to OP's question - I think it was Petzl (but might have been BD) that measured a difference in peak force between nylon sport draws and Dyneema draws in a realistic sport climbing lead fall simulation. So even with a rope involved, the little extra "give" of nylon draws makes a (small) difference.

It was BD that did the test

The result was nylon was .5kn, 4.7% lower in peak force than spectra and steel chain.

Perhaps this is a bit more psychological than realistically adding strength to marginal pieces, but that is sometimes all one needs. For mission critical pieces I typically use a nylon shoulder sling with a locker and I ever so slightly more secure climbing above it, which is sometimes just enough to get me through an insecure section of climbing.

Additionally, tests by the DAV also conclude that spectra/nylon blends experience a slower strength loss than [almost] pure spectra, and pure nylon webbing losing strength even slower. I believe this is due to UV neutral treatment that is applied to nylon textiles so spectra experiences much quicker and more severe degradation from UV exposure.

U worries about lowering impact forces on ur pieces?

- use a beal rope

- dont use a grigri

- make sure your rope path is as straight as possible with the least friction

Thats all there is to it

;)