Cut Resistance of Ropes: Part 3 | EDELRID Knowledge Base

[@colinwalker1626]

Philippe, I believe the cut resistance research that you and Edelrid are doing is the most important rope research being done today. Thank you!

[@LeifMahoney]

That cutting length vs breaking strength graph looked suspiciously like a linear relationship for it to be dismissed so quickly.

[@andrewhunter6536]

That stands out to me as well. Makes it feel a little cherry picked and makes the jump to 160kg “to better compare” seem a little suspicious too. Perhaps the description links to a write up though where it is more clear. I am not say they had pre decided the conclusion and worked build evidence for that. Just that from the video alone some choices are a little clunky. Will look for a write up now

[@philippewestenberger9087]

Hey, yes I agree that this particularly data set doesn't look as obviously dismissive as the others. However, we of course looked deeper into this (as well as many other facettes not even shown here in this video) and the conclusions still stands that tensile strength does not reliably influence the cut value. Otherwise, this would also have been really low hanging fruit for us and other rope manufacturer. Unfortunately it is not so easy as just to control tensile strength :) We could easily construct ropes with little tensile strength and a great cut value. Maybe an example for this could also be seen at 7:34 where we show the results of a 7mm cord with a much higher cut value then one 11mm rope. For sure the 11mm rope has a much higher tensile strength than the 7mm rope.

[@eliottwiener6533]

Thanks for the informative video. Not knowing much about this topic, I was surprised by the degree to which rope construction can affect cut resistance. I would have expected the aramid sheath rope to easily come out on top. Has there been any progress toward a new UIAA standard for cut resistance based on this testing methodology?

[@bt5294]

Can you make a bipattern protect rope?

[@turquoisecrayfish]

Great video and I think really important message. Hopefully there will be an agreed upon UIAA standard soon that is reliable and cost-effective to implement. Can you shed any light on the differences in cut resistance between the following 3 ropes? Edelrid Boa 9.8 - cut 19 Edelrid Boa Gym 9.8 - cut 32 Edelrid Heron Eco Dry 9.8 - cut 28 All are the same diameter, have similar sheath proportions but the Boa Gym and Heron Eco Dry have +50% cut resistance compared to the standard Boa! I'm assuming the difference is caused by sheath weave type / sheath weave tightness?

[@edelrid]

Another great example underlining one of the main points in this video - that diameter is no reliable measurement fur the cut value of a rope. All of your mentioned rope models are completely different constructions. The BOA GYM for example includes Polyester in its sheath as well as a different braiding pattern for the sheath compared to the other two. The HERON is more similar to the BOA, but also has slight deviations in constructions and material quantity resulting in slightly different characteristics like e.g. stiffness. Further, it also includes a chemical treatment to pass the UIAA water repellent test. All differences that at the end make a difference in the overall cut value of those ropes. I guess it is really time, that we can rely on a proper test to judge this, don’t you think?

[@turquoisecrayfish]

@@edelrid yep I would agree. Can you give any info on how the different sheath braids affect a rope? Your website braiding article says the twill braid gives better abrasion resistance but is more slippy to hold and can lead to more sheath slippage when compared to plain braid - any more advantages or disadvantages? Also what are the benefits and disadvantages of the number of bobbins? Does more bobbins give a smoother sheath? What are the disadvantages - cost? How does the number of bobbins affect cut resistance and abrasion resistance? Thanks!

[@edelrid]

@@turquoisecrayfish glad that there is such a relentless interest in the details of rope! This is something we of course share and sadly a rope is often discarded as “just a rope”. However, very often it is not as simple as it might sound. As for the different sheath patterns, you probably already found the best source we provide about the advantages and disadvantages of the different patterns. More reasons for and against a certain pattern are not really noticeable or visible for a user and are therefore often production and construction related. To go into detail here would probably go beyond this format of communication. The same goes for different carrier machines. In general yes: more bobbins make for a less coarsely braided sheath. So in general another option to get a smoother sheath or more material in the sheath. However, what you have to understand about ropes is that it is simply not possible to draw any conclusions about the resulting properties of a rope from one technical condition. It is always a combination of all factors. And there are a lot of them! So it could be that a 48 carrier is chosen for a rope because its advantages equalizes other disadvantages resulting from other construction characteristics. Same goes for the above mentioned sheath pattern. So what counts are the technical data of a rope and how you think it handles in practice for your purposes. Don’t short cut and conclude because it has this feature it must be like that characteristic. This might not be totally satisfactory, but this is how textiles work 😊

[@Govanification]

"In recent episodes" lol parts 1&2 were 4 years ago. But thanks for the awesome tech developments!

[@edelrid]

Better late than never!

[@andrewhunter6536]

You have the data for this in a table or short write up? You seem to blow past a pretty decent correlation of strength and cut resistance but without knowing what was actually cut it isn’t possible to see if that is just a material difference. Making the data available would be very helpful and interesting

[@edelrid]

Please click on our video description :) there you'll find links to other videos within this series, as well as relevant Knowledge Base articles.

[@andrewhunter6536]

@@edelrid I did not see the raw data from this video saying what the rope construction or type was for each test here. Maybe a table like that has been added since or maybe I missed it? Where can I find the data from this specific test saying the rope or rope material and the cutting length? Basically where would I see the number you used to make the plots in this video?

[@philippewestenberger9087]

@@andrewhunter6536 Hey, yes I agree that this particularly data set doesn't look as obviously dismissive as the others. However, we of course looked deeper into this (as well as many other facettes not even shown here in this video) and the conclusions still stands that tensile strength does not reliably influence the cut value. Otherwise, this would also have been really low hanging fruit for us and other rope manufacturer. Unfortunately it is not so easy as just to control tensile strength :) We could easily construct ropes with little tensile strength and a great cut value. Maybe an example for this could also be seen at 7:34 where we show the results of a 7mm cord with a much higher cut value then one 11mm rope. For sure the 11mm rope has a much higher tensile strength than the 7mm rope.

[@suskepicious]

You werent going to name and shame but which rope was it that had the 120 cm cutting reistance ? was it a heat resistant rope ? They feel so much safer and well made.

[@philippewestenberger9087]

We try to stay as neutral as possible within the knowledge base. This is not about products, it should be about a message. And the beautiful thing in this case here is, that we can also braid whatever we want to test ourselves here in our production. Then it is not a known product, but a test sample :) And on another note: heat resistance is not a defined term, but a marketing buzz word. We will also publish something about this within this year I hope :)

[@andrewhunter6536]

@@philippewestenberger9087will you publish the data with info about the ropes? I asked in a top line comment with more reasons but thought to ask here too

[@VALERYAN581]

more about this.Ripstop is good ,for static rops ? I like that 9,5 mm but all my descenders work 10 to 12 mm .

[@joshuawiedmann3870]

Just to make sure we all understand: Episode 1: At 1:59 you present a graph showing the leading cause of accidents to be of severed ropes due to sharp objects. Episode 2: You display your testing techniques to provide a sense of legitimacy for the following results in episode 3 Episode 3: You display results of your testing, but refused to make a recommendation based upon said results Conclusion: Politics If my goal was to find the safest child car seat, then do crash tests on child car seats, then find the best one but refuse to mention the brand or model of the best performer, I have lost the reason for testing. You have basically said nothing that would help save lives even though your stated goal was to help save lives. These series of videos had NOTHING to do with saving lives or helping the climbing community. This was a publicity stunt to bring your company business and hopefully sell products. Prove me wrong. Show us which brands and models you tested and which one was the best performer. I bet you won't.

[@philippewestenberger9087]

Good that you want to clarify that, because in my opinion you are drawing the wrong conclusions ("for us all") out of this as well as missing the most important ones. But I try to explain in my words: - Severed ropes due to sharp objects are not generally the leading cause of accidents, but sharp edges are the number one cause for all accidents due to a severed rope. - The main take-away from Episode 2 is the influence of weight in a rope system on the overall safety regarding sharp edges. It shows, that independent on how safe your rope might be or not be, if you have the chance to lower the weight applied to it, the gains in safety will be much greater than any cut resistant characteristics of your rope. - The intention of Episode 3 ist to show, that we urgently need a way to quantify cut resistance of ropes as currently climbers can not judge the safety of their rope in regards to sharp objects with the data they get provided. And staying with that last point. Your shown frustration of not knowing what rope might be the best for your purposes in regards to sharp objects is exactly the point made. And we would like to change this. Maybe we just differ in the approach here. For one, we put 6 years of research into building a test-setup that now, for the first time, provides the possibility to quantify this characteristic for ropes (not as trivial as it might seem, but you saw Episode 1 to understand this). We also provide the cut values within our own rope range for all our dynamic ropes. So within our rope range you can perfectly see which would suit you best. And we also have used the knowledge we gained in those years of research to built products that are perfectly optimized towards the characteristic in question. What this whole topic is to us here in the development though, is anything but a marketing stunt. We strongly believe in the importance of this proven number one risk for rope failure and will do anything that this is taken seriously and exactly not as a promotion. If we were to publish the values of all our competitors, it would not only be an unfair and disrespectful behaviour towards our competitors, it would then really look like and be a marketing stunt! Knowledge Base videos should be as neutral a source of information as possible and not a product marketing tool! The content comes from the development team, not from any of our commercial departments. And with this in mind, our approach in this matter is to talk about practical implications of our research as well as raise awareness for the urgent need of such a test. We are actively seeking dialogue with our competitors on a factual level and in a working group within the UIAA currently that has been set up specifically for this purpose, we are trying to develop a standard that will subsequently apply to everyone and which will make information about a cut value not only visible then but also objectively reliable for the user.