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Rope Specs and Differences between Brands: Falls Held
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mattm


Oct 26, 2010, 11:44 AM
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Rope Specs and Differences between Brands: Falls Held
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I'm pretty savvy on rope mechanics, specs etc. The only ones I truly look at are Impact Force, Falls Held and gr/m weight. Maybe sheath percentage as well. The others are a bit less informative and a lot of the time you need a hands on to evaluate how a rope is "built".

So here's the tech question of the day. Why is there a HUGE difference in # of falls held between two ropes that seem SOMEWHAT similar. I realize these are due to design intents to some degree but I wonder about WHY these choices were made.

Specific Example: Beal vs Sterling. I've been a Beal guy for the past few years due to impact force ratings. My local climbing area changed and that's not a huge issue anymore (mostly bolted sport now vs: trad) so I've been looking at some Sterlings that many people swear by.

A Sterling Marathon Pro 10.1mm Specs out at 6 falls, 8.6kN and 63g/m - No Sheath % listed.

A Beal Flyer 10.2mm Specs out at 10 Falls, 7.4kN and 64g/m, 38% Sheath.

There are slight differences in the specs but what stands out to me id the # of falls held. Seems like a BIG difference given that A) the min is 5 and B) The beal is only slightly larger.

Is # of Falls Held a less relevant stat than I'm thinking it is? Is it not the indication of durability that I think it is?

Why design a rope to just barely make the falls held when others double it? What's the thought process here? Just want to educate my self and satisfy my inner engineer a bit more.


(This post was edited by mattm on Oct 26, 2010, 11:45 AM)


kennoyce


Oct 26, 2010, 11:58 AM
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Re: [mattm] Rope Specs and Differences between Brands: Falls Held [In reply to]
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mattm wrote:
I'm pretty savvy on rope mechanics, specs etc. The only ones I truly look at are Impact Force, Falls Held and gr/m weight. Maybe sheath percentage as well. The others are a bit less informative and a lot of the time you need a hands on to evaluate how a rope is "built".

So here's the tech question of the day. Why is there a HUGE difference in # of falls held between two ropes that seem SOMEWHAT similar. I realize these are due to design intents to some degree but I wonder about WHY these choices were made.

Specific Example: Beal vs Sterling. I've been a Beal guy for the past few years due to impact force ratings. My local climbing area changed and that's not a huge issue anymore (mostly bolted sport now vs: trad) so I've been looking at some Sterlings that many people swear by.

A Sterling Marathon Pro 10.1mm Specs out at 6 falls, 8.6kN and 63g/m - No Sheath % listed.

A Beal Flyer 10.2mm Specs out at 10 Falls, 7.4kN and 64g/m, 38% Sheath.

There are slight differences in the specs but what stands out to me id the # of falls held. Seems like a BIG difference given that A) the min is 5 and B) The beal is only slightly larger.

Is # of Falls Held a less relevant stat than I'm thinking it is? Is it not the indication of durability that I think it is?

Why design a rope to just barely make the falls held when others double it? What's the thought process here? Just want to educate my self and satisfy my inner engineer a bit more.

To answer your question to the best of my ability, I do think that the number of falls held has nothing to do with the durability of a rope. The UIAA test falls are so much more severe than any fall that you can take in a real climbing situation (including factor 2's because of the rigid connections during the test) that they are not a good indicator of a ropes durability. As for the reason behind the different number of falls held I can only speculate, but I would guess that it has something to do with the ratio of sheath vs core since the marathon has such a burly sheath. The core is the part of the rope that dissipates most of the energy of a fall, so having less core would most likely translate into fewer UIAA falls.


mattm


Oct 26, 2010, 12:02 PM
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Re: [kennoyce] Rope Specs and Differences between Brands: Falls Held [In reply to]
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I figured it had to do with sheath design vs core to some degree.

Maybe Sterling Jim can respond to design considerations (if no a trade secret!).

It does seem a bit counterintuitive that the ability to absorb more energy might make it "less durable"

I guess it's all in how you define "durable" which is probably part of the answer to design choices and why...

Does anyone know of any real-world stats on what "kills" a rope first. Gut tells me sheath wear. Curious if visual sheath wear has that much of an effect on rope strength.


(This post was edited by mattm on Oct 26, 2010, 12:04 PM)


vegastradguy


Oct 26, 2010, 12:06 PM
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Re: [mattm] Rope Specs and Differences between Brands: Falls Held [In reply to]
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i should probably call the boys at sterling for a better answer, but my gut tells me that number of falls held really isnt all that important.

a little bit of research on the sterling site may reveal the answer- the Marathon rope apparently uses a heavier denier nylon than a standard climbing line for its sheath- which may account for the lower falls. the sterling Kosmos, its other 10.2 line, clocks in at 8 falls- and has what i would assume to be a more traditional nylon in the sheath.

for what its worth, my rope of choice is the Velocity and at 6 falls, its burly as hell- its lasted longer than any other 9.8 line i've used. i also know that their Ion and Nano have also gotten great reviews on durability, despite the low # of falls held.


vegastradguy


Oct 26, 2010, 12:09 PM
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Re: [mattm] Rope Specs and Differences between Brands: Falls Held [In reply to]
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mattm wrote:
It does seem a bit counterintuitive that the ability to absorb more energy might make it "less durable"

well, considering the core is what does the majority of the work in absorbing energy and the sheath is really what accounts for durability, the balance between those two strikes me as you getting to pick one or the other.


crackalackin


Oct 26, 2010, 12:16 PM
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Re: [mattm] Rope Specs and Differences between Brands: Falls Held [In reply to]
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It's in part the sheath vs. core ratio - and also, just because it states the rope as a 10.1mm diameter doesn't mean it's a true 10.1. With UIAA, there is a tolerance of .3 mm in either direction to claim a particular diameter. Though the difference seems minimal, it could mean even one more or one less core strand which can make a difference with strength. (If you have two 10.1 ropes, and one is actually 9.8 and the other is truly 10.4... that can be a fairly significant difference) As for what kills a rope - sheath wear is not a concern unless it interferes with operating your equipment. Almost all of the strength of your rope lies within the core, and the sheath acts as a protective barrier. So if your rope is fuzzy and fatter, it doesn't necessarily mean it has lost its strength, but it could interfere with proper feeding through your belay device...


Fayettevillain


Aug 2, 2012, 8:59 AM
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Re: [mattm] Rope Specs and Differences between Brands: Falls Held [In reply to]
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The number of test falls held indicates how many UIAA certified falls a given rope can sustain before breaking. The testing procedure - dropping a 176 pound weight attached to an 8.25 foot length of rope a distance of 16.5 feet - yields a very severe fall which would be difficult to duplicate in any but the worst actual climbing situation. It is important to note that ropes lose elasticity, and their ability to absorb energy, when subjected to repeated falls.

While the CE/UIAA has set standards for these tests, all of the results are pass/fail. A CE/UIAA label indicates that the rope has passed the minimum tests only. Any other information listed on the rope label is at the manufacturer's discretion. Number of falls, impact force, etc. are all based on the manufacturer's claims, which may be based on theoretical estimation, and not necessarily on test results.

for more: http://www.ussartf.org/ropes_knots.htm
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atpclimbing


Aug 5, 2012, 1:48 PM
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Re: [mattm] Rope Specs and Differences between Brands: Falls Held [In reply to]
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Impact force, dynamic elongation, and weight are the things to look at. Falls held has nothing to do with real world use.

Low impact force combined with low dynamic elongation make for the best ropes imo. The Sterling Velocity is pretty damn good in those categories (and holds plenty of UIAA falls).

My Velocity has held up pretty well along with the Marathon Pro I've got. They both can handle plenty of abuse down in the Red. Except for the dirt and some slight sheath fuzziness both are going strong after uncounted falls.

Can't go wrong with Sterling.


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