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hi all,i was just wondering what people thought about this.
I bought a new skinny single rope to pair with a beal 8.6 half rope,the rope is triple rated and i wanted to use it mainly with the beal for short cragging routes but still have the option to use it on its own,ive done this before with a mammut triple rated rope which lasted very well considering its reduced sheath proportion.
Ive been using a pair of mammut 8mm ropes(actually a 100m duodess chopped in half)when i have had to supply both half ropes for cragging and they have lasted for years(6 maybe)they have taken many short falls on natural and quarried grit,rubbed over rough gritstone with seconds hanging on the rope etc on to many occasions to remember and still look like decent ropes,i normally use the beal 8.6 when the person im climbing with has a half rope(which is usually of similar diameter),the only reason i was promted to buy another half rope to match the beal was the guy ive been climbing with lately fell a couple of times on the 8 mils and hes quite a bit bigger than me and he seemed to come a long way down with no rope slip just stretch and it made me think maybe the 8 mils are ok if your 10 stone like me on short routes but bigger folk might benefit from something a bit thicker especially on short cragging type routes,anyway one thing led to another and i considered the extra on the triple rated skinny single worth it for the option of using it on its own.
Now i know these skinny singles are not meant for working routes,they are not sold as a durable rope and i accept all the limitations etc,but what do people think ?,the mammut skinny single only ever got slightly fluffy from using on grit several times and the 8 mils seem to be indestructable !.
The rope has done about 16-18 routes on quarried and natural grit,from what i can remember it has taken 4-6 small slumps just above gear and 2,4-5m falls,i can remember in one day the mammut skinny single having more falls that,the 8 mils more than i could possibly remember.
Heres a link to some pics,a pic of what a good section of rope looks like a pic of how fluffy parts of it was after a couple of uses and pics of the 2 areas that have gone to the core.
http://s1372.photobucket.com/user/cliffshaz/library/
cheers cliff..
I bought a new skinny single rope to pair with a beal 8.6 half rope,the rope is triple rated and i wanted to use it mainly with the beal for short cragging routes but still have the option to use it on its own,ive done this before with a mammut triple rated rope which lasted very well considering its reduced sheath proportion.
Ive been using a pair of mammut 8mm ropes(actually a 100m duodess chopped in half)when i have had to supply both half ropes for cragging and they have lasted for years(6 maybe)they have taken many short falls on natural and quarried grit,rubbed over rough gritstone with seconds hanging on the rope etc on to many occasions to remember and still look like decent ropes,i normally use the beal 8.6 when the person im climbing with has a half rope(which is usually of similar diameter),the only reason i was promted to buy another half rope to match the beal was the guy ive been climbing with lately fell a couple of times on the 8 mils and hes quite a bit bigger than me and he seemed to come a long way down with no rope slip just stretch and it made me think maybe the 8 mils are ok if your 10 stone like me on short routes but bigger folk might benefit from something a bit thicker especially on short cragging type routes,anyway one thing led to another and i considered the extra on the triple rated skinny single worth it for the option of using it on its own.
Now i know these skinny singles are not meant for working routes,they are not sold as a durable rope and i accept all the limitations etc,but what do people think ?,the mammut skinny single only ever got slightly fluffy from using on grit several times and the 8 mils seem to be indestructable !.
The rope has done about 16-18 routes on quarried and natural grit,from what i can remember it has taken 4-6 small slumps just above gear and 2,4-5m falls,i can remember in one day the mammut skinny single having more falls that,the 8 mils more than i could possibly remember.
Heres a link to some pics,a pic of what a good section of rope looks like a pic of how fluffy parts of it was after a couple of uses and pics of the 2 areas that have gone to the core.
http://s1372.photobucket.com/user/cliffshaz/library/
cheers cliff..
In reply to cliff shasby:
I have always used either a pair of Jokers, or a pair of Cobra's, and never had a problem like what I see in your pics. And the ropes I use get some serious usage.
Tell me what rope it was so I don't buy one the same.
Actually, don't reply if it is a Cobra or Joker (although it does not look like either).
I have always used either a pair of Jokers, or a pair of Cobra's, and never had a problem like what I see in your pics. And the ropes I use get some serious usage.
Tell me what rope it was so I don't buy one the same.
Actually, don't reply if it is a Cobra or Joker (although it does not look like either).
In reply to cliff shasby:
TBH I think you've got more money than sense for using an expensive skinny single on grit in the first place and that you're a complete lunatic for taking "4-6 small slumps just above gear and 2,4-5m falls" on it in so few routes.
That said, in the interest of a fuller picture, what crags and routes were you climbing on?
When I was out last winter in Glencoe, we trashed a Beal Joker doing some general mountaineering. It was PYB's so we weren't too upset, but it happens quickly and easily enough.
Despite the fact most of my ropes have lasted superbly (touch wood!), my mindset is always that ropes are expendable and therefore it's always sensible to use the cheapest option that's still suitable. For me, on grit that invariably means the cheapest 30m single available.
FWIW I trashed my first half rope on grit many moons ago, and that probably still influences my judgement now.
> but what do people think ?
TBH I think you've got more money than sense for using an expensive skinny single on grit in the first place and that you're a complete lunatic for taking "4-6 small slumps just above gear and 2,4-5m falls" on it in so few routes.
That said, in the interest of a fuller picture, what crags and routes were you climbing on?
When I was out last winter in Glencoe, we trashed a Beal Joker doing some general mountaineering. It was PYB's so we weren't too upset, but it happens quickly and easily enough.
Despite the fact most of my ropes have lasted superbly (touch wood!), my mindset is always that ropes are expendable and therefore it's always sensible to use the cheapest option that's still suitable. For me, on grit that invariably means the cheapest 30m single available.
FWIW I trashed my first half rope on grit many moons ago, and that probably still influences my judgement now.
In reply to The Ex-Engineer:
It was an assortment of routes from hvs-e3 in the lancs qurries and peak grit,my point is that i have had a serenity and am still using 8mm ropes with loads of falls and weighted abrasion on grit that are still perfectly usable ropes.
I also consider ropes expendable and if i had got a year out of this rope i would have thought fair enough,but one month..?,it seems so much less durable than mammuts equivalent.
As far as the money goes,i look at it that its like a months worth of climbing petrol money,not that much in the grand scheme of things,but i would say its a bit excessive for a months use..!
It was an assortment of routes from hvs-e3 in the lancs qurries and peak grit,my point is that i have had a serenity and am still using 8mm ropes with loads of falls and weighted abrasion on grit that are still perfectly usable ropes.
I also consider ropes expendable and if i had got a year out of this rope i would have thought fair enough,but one month..?,it seems so much less durable than mammuts equivalent.
As far as the money goes,i look at it that its like a months worth of climbing petrol money,not that much in the grand scheme of things,but i would say its a bit excessive for a months use..!
In reply to cliff shasby:
That kind of wear isn't caused by falling, it's caused by a tight rope scraping across rough rock, particularly edges.
That kind of wear isn't caused by falling, it's caused by a tight rope scraping across rough rock, particularly edges.
In reply to cliff shasby:
Lots of the triple rated ropes seem to wear pretty quick - I seem to remember it being because they have more core than a half (to get the single rating)
and less sheath (to keep them skinny and light).
I regularly climb on one half rope without trashing it.
Lots of the triple rated ropes seem to wear pretty quick - I seem to remember it being because they have more core than a half (to get the single rating)
and less sheath (to keep them skinny and light).
I regularly climb on one half rope without trashing it.
In reply to cliff shasby:
a good friend trashed a triple single 2nd day out lowering over a not obviously sharp/abrasive edge as others have said it's probably your seconds slumping.
I feel your pain!
a good friend trashed a triple single 2nd day out lowering over a not obviously sharp/abrasive edge as others have said it's probably your seconds slumping.
I feel your pain!
In reply to cliff shasby:
I did a while ago have a bit of a run of leading and falling off (indoors) and did manage to knacker a (cheap single wall-) rope within a couple of months (flat spots, mainly). I'm 17 stone now and was a bit heavier (maybe 19 stone) back then. So it can happen.
My current one has lasted a couple of years so far, though. So it seems it can vary. Though I fall off less than I used to (though did this evening and bashed my foot, ouch).
Neil
I did a while ago have a bit of a run of leading and falling off (indoors) and did manage to knacker a (cheap single wall-) rope within a couple of months (flat spots, mainly). I'm 17 stone now and was a bit heavier (maybe 19 stone) back then. So it can happen.
My current one has lasted a couple of years so far, though. So it seems it can vary. Though I fall off less than I used to (though did this evening and bashed my foot, ouch).
Neil
In reply to Steeve:
I tested these three http://www.ukclimbing.com/gear/review.php?id=3765 triple rated ropes, plus I had had a Beal Joker for a number of years previous to that review and used a Mammut Revolution (9mm single) for some years previous to that. All of them have lasted perfectly well. Of course they're not great 'project' ropes but none of the ones I've used have been bad.
BUT I have the same rope that Cliff has for testing for a future UKC review - it's the Edelrid Corbie - and managed to damage it twice to the core within the first three days of using it. The first time necessitated cutting about 8 mtrs off. The second time meant basically cutting the rope in half. I was thinking that perhaps I had just been incredibly unlucky, but the damage looked just like the damage in Cliff's photos - it has to be something about the construction of the rope's mantle that makes it prone to this surely? The odd thing is, Edelrid provided two ropes for testing - so I could test them as doubles/twins also - and the second rope is absolutely fine after a few days now of hard cragging, people falling on it, people lowering off with it, seconds top roping through top anchors etc.
> Lots of the triple rated ropes seem to wear pretty quick - I seem to remember it being because they have more core than a half (to get the single rating)
I tested these three http://www.ukclimbing.com/gear/review.php?id=3765 triple rated ropes, plus I had had a Beal Joker for a number of years previous to that review and used a Mammut Revolution (9mm single) for some years previous to that. All of them have lasted perfectly well. Of course they're not great 'project' ropes but none of the ones I've used have been bad.
BUT I have the same rope that Cliff has for testing for a future UKC review - it's the Edelrid Corbie - and managed to damage it twice to the core within the first three days of using it. The first time necessitated cutting about 8 mtrs off. The second time meant basically cutting the rope in half. I was thinking that perhaps I had just been incredibly unlucky, but the damage looked just like the damage in Cliff's photos - it has to be something about the construction of the rope's mantle that makes it prone to this surely? The odd thing is, Edelrid provided two ropes for testing - so I could test them as doubles/twins also - and the second rope is absolutely fine after a few days now of hard cragging, people falling on it, people lowering off with it, seconds top roping through top anchors etc.
Post edited at 06:47
In reply to cliff shasby:
I'm really not fussy about ropes, even got told off by the mods on ukc for posting that it was ok to use a 30 year old rope, but I'd say yours was knackered. All you can do is cut it where it's damaged if the the remaining bit are long enough to be used. It might be worth going back to where you bought it, they may have had a bad batch of ropes and if you are not the only one perhaps they'll change it?
I'm really not fussy about ropes, even got told off by the mods on ukc for posting that it was ok to use a 30 year old rope, but I'd say yours was knackered. All you can do is cut it where it's damaged if the the remaining bit are long enough to be used. It might be worth going back to where you bought it, they may have had a bad batch of ropes and if you are not the only one perhaps they'll change it?
In reply to TobyA: interesting. An Edelrid product that has been made too lightweight...
In reply to mike kann:
Did you see that photo I tagged you in on FB Mike? I'm still pretty impressed with both the micro and mega jul. The autolock abseil mode worked very well when I tried it.
Did you see that photo I tagged you in on FB Mike? I'm still pretty impressed with both the micro and mega jul. The autolock abseil mode worked very well when I tried it.
In reply to TobyA:
Yep. You're not ever going to convince me that a massively undersized belay plate made of a heat retaining material that is harder than all the hardware it's in contact with is ever going to be a good design decision. A bit like making via ferrata kits with lighter and lighter sling until they are no longer durable. Or rope with such a low sheath percentage is ever going to be a rope I'd want to take alpine climbing. Want to know why the sheath ruptures easily? 29% sheath as compared to 38% for the serenity at a similar impact force. Simples. I'll take the Mammut.
Yep. You're not ever going to convince me that a massively undersized belay plate made of a heat retaining material that is harder than all the hardware it's in contact with is ever going to be a good design decision. A bit like making via ferrata kits with lighter and lighter sling until they are no longer durable. Or rope with such a low sheath percentage is ever going to be a rope I'd want to take alpine climbing. Want to know why the sheath ruptures easily? 29% sheath as compared to 38% for the serenity at a similar impact force. Simples. I'll take the Mammut.
Post edited at 09:57
In reply to mike kann:
The Serenity's dry treatment is a bit pants, freeze up easily. I'd go for the Joker. The sheaf percentage is interesting I've just looked at it for all the other Edelrid ropes, so the Corbie has unsurprisingly the lowest, but it is only within mainly a range of about 10%. A few models have over 40% but not so many.
The Serenity's dry treatment is a bit pants, freeze up easily. I'd go for the Joker. The sheaf percentage is interesting I've just looked at it for all the other Edelrid ropes, so the Corbie has unsurprisingly the lowest, but it is only within mainly a range of about 10%. A few models have over 40% but not so many.
In reply to TobyA:
Trying to measure and compare rope wear and durability in the field is a bit of a nonsense because you can't provide a fair test.
Why? Well, any single fall event can produce devastating damage to a rope, requiring its immediate retirement. I once watched someone fall off an E4 at Stanage and completely strip the sheath from a brand new 10.5mm rope, one of the most durable on the market at the time. In such a situation, the circumstances of the fall are far more important than the rope construction or materials.
You have to be extremely careful about drawing conclusions regarding the general durability and sturdiness of a rope from user experience because of this - in effect every time you fall off you are entering a "rope damage lottery".
The best solution would be an abrasion test as part of the rope standard, but there are practical reasons why there isn't one.
As for general advice - if you intend to fall off a lot, using a cheap heavy duty rope sounds like a great idea, save your nice lightweight ropes for mountain and alpine routes and for sport redpoints.
Trying to measure and compare rope wear and durability in the field is a bit of a nonsense because you can't provide a fair test.
Why? Well, any single fall event can produce devastating damage to a rope, requiring its immediate retirement. I once watched someone fall off an E4 at Stanage and completely strip the sheath from a brand new 10.5mm rope, one of the most durable on the market at the time. In such a situation, the circumstances of the fall are far more important than the rope construction or materials.
You have to be extremely careful about drawing conclusions regarding the general durability and sturdiness of a rope from user experience because of this - in effect every time you fall off you are entering a "rope damage lottery".
The best solution would be an abrasion test as part of the rope standard, but there are practical reasons why there isn't one.
As for general advice - if you intend to fall off a lot, using a cheap heavy duty rope sounds like a great idea, save your nice lightweight ropes for mountain and alpine routes and for sport redpoints.
In reply to Dan Middleton, BMC:
Yes, and the manufacturers fairly say that a rope can be damaged on its first use so that you need to retire it (or at least cut it). Of course that would be heart breaking if you have just bought it, but I suspect most people accept these things can happen. I said to Edelrid that of course it COULD have been simply exceedingly bad luck how I damaged the rope I was testing, but twice in two days of climbing did seem like a pattern developing, this is when compared to over a decade of climbing the same or similar routes on the same of similar crags with a variety of different ropes and not seeing this happen (although of course I have cut down many ropes due to wear over the years, just not so quickly in their usage-life). Seeing that someone else has managed to get similar damage only adds to the feeling that there could be something about the weave of this rope? Of course it is anecdotal, but once you gather enough anecdotes eventually that constitutes a data set.
What do you think of Mike's point above about sheath thickness as a proportion of the rope? Would you expect that a rope with a thicker sheath will be harder wearing than one with less? Or will it still be something of a lottery? I was wondering whether other factors - say a slightly looser weave of kern and then crystalline rock that could catch the that weave - might be as or more important than the thickness of the sheath as a proportion of the rope (or it's just actual thickness alone)?
Yes, and the manufacturers fairly say that a rope can be damaged on its first use so that you need to retire it (or at least cut it). Of course that would be heart breaking if you have just bought it, but I suspect most people accept these things can happen. I said to Edelrid that of course it COULD have been simply exceedingly bad luck how I damaged the rope I was testing, but twice in two days of climbing did seem like a pattern developing, this is when compared to over a decade of climbing the same or similar routes on the same of similar crags with a variety of different ropes and not seeing this happen (although of course I have cut down many ropes due to wear over the years, just not so quickly in their usage-life). Seeing that someone else has managed to get similar damage only adds to the feeling that there could be something about the weave of this rope? Of course it is anecdotal, but once you gather enough anecdotes eventually that constitutes a data set.
What do you think of Mike's point above about sheath thickness as a proportion of the rope? Would you expect that a rope with a thicker sheath will be harder wearing than one with less? Or will it still be something of a lottery? I was wondering whether other factors - say a slightly looser weave of kern and then crystalline rock that could catch the that weave - might be as or more important than the thickness of the sheath as a proportion of the rope (or it's just actual thickness alone)?
In reply to TobyA:
The weave will depend on the amount of stretch they are aiming for - the lower impact force they are aiming for the more the rope must stretch and the more angular the weave must be (simplifying it a lot!) as the sheath needs to be able to move with the core. Angular weave means looser sheath unless it's carefully made, and that means it's easier to unpick threads. The thing I find interesting in the stats is that Serenities have a similar impact force to the corbie despite their 10% Higher sheath proportion. The sheath is what gives it's durability so it stands to reason that in normal use which is unlike to compromise the sheath, the Mammut will wear better simply because there is more sheath to get through before exposing the core.
The weave will depend on the amount of stretch they are aiming for - the lower impact force they are aiming for the more the rope must stretch and the more angular the weave must be (simplifying it a lot!) as the sheath needs to be able to move with the core. Angular weave means looser sheath unless it's carefully made, and that means it's easier to unpick threads. The thing I find interesting in the stats is that Serenities have a similar impact force to the corbie despite their 10% Higher sheath proportion. The sheath is what gives it's durability so it stands to reason that in normal use which is unlike to compromise the sheath, the Mammut will wear better simply because there is more sheath to get through before exposing the core.
In reply to TobyA:
There is no question that a high sheath proportion and a tight sheath construction will improve the longevity of a rope when it comes to protection from abrasion caused when lowering off and abseiling. A high sheath percentage is a feature on most gym ropes, for example. It probably makes some difference too in falls, but there is still the proviso that in some situations the thickest sheath will still rupture or be badly damaged.
There is no question that a high sheath proportion and a tight sheath construction will improve the longevity of a rope when it comes to protection from abrasion caused when lowering off and abseiling. A high sheath percentage is a feature on most gym ropes, for example. It probably makes some difference too in falls, but there is still the proviso that in some situations the thickest sheath will still rupture or be badly damaged.
In reply to cliff shasby:
That's a pretty sorry tale you tell, but my guess is that you've just been very unlucky in the nature of your falls/slumps. I got an Edelrid Falcon a few months ago (9.4mm) and it's superb. Ok, so it's slightly like comparing apples and oranges, but the handling and robustness are both excellent on the Falcon. Incidentally, 8.6mm is pretty damned skinny for a single!
That's a pretty sorry tale you tell, but my guess is that you've just been very unlucky in the nature of your falls/slumps. I got an Edelrid Falcon a few months ago (9.4mm) and it's superb. Ok, so it's slightly like comparing apples and oranges, but the handling and robustness are both excellent on the Falcon. Incidentally, 8.6mm is pretty damned skinny for a single!
In reply to Steeve:
That's quite interesting. Just doing a quick comparison on the internet:
The Corbie has a Sheath % of 29, meaning that for an 8.6mm rope the core is about 2.5mm thick.
For a Mammut Obsession half rope, the sheath % is 45, so for an 8.3mm rope the sheath is 3.7mm.
That means the sheath on the half rope is 1.5 times thicker than the single, despite being a thinner rope.
> Lots of the triple rated ropes seem to wear pretty quick - I seem to remember it being because they have more core than a half (to get the single rating) and less sheath (to keep them skinny and light).
That's quite interesting. Just doing a quick comparison on the internet:
The Corbie has a Sheath % of 29, meaning that for an 8.6mm rope the core is about 2.5mm thick.
For a Mammut Obsession half rope, the sheath % is 45, so for an 8.3mm rope the sheath is 3.7mm.
That means the sheath on the half rope is 1.5 times thicker than the single, despite being a thinner rope.
In reply to alasdair19:
cheers Al, I didn't set out to damage cliffs rope and to be honest i wasn't all that up for climbing the e2/e3,s that i slumped on,but rather was encouraged to have a go,get the feel off them.I text cliff and told him he can have my mammut
john
cheers Al, I didn't set out to damage cliffs rope and to be honest i wasn't all that up for climbing the e2/e3,s that i slumped on,but rather was encouraged to have a go,get the feel off them.I text cliff and told him he can have my mammut
john
In reply to RyanOsborne:
Not sure about your maths there. Care to elaborate?
> That's quite interesting. Just doing a quick comparison on the internet:
> The Corbie has a Sheath % of 29, meaning that for an 8.6mm rope the core is about 2.5mm thick.
> For a Mammut Obsession half rope, the sheath % is 45, so for an 8.3mm rope the sheath is 3.7mm.
> That means the sheath on the half rope is 1.5 times thicker than the single, despite being a thinner rope.
Not sure about your maths there. Care to elaborate?
In reply to RyanOsborne:
2.5mm on each side of a core means you've 5mm of sheath, which is 58% of an 8.6mm diam. rope not 29%. I assume that's what he means...
Edit: I took your figure for the sheath (which I shouldn't have.) 29% of an 8.6mm rope gives a total sheath of 2.494mm which is on both 'sides' of a rope, so the amount of sheath you wear through before hitting the core is actually half that ie about 1.25mm.
2.5mm on each side of a core means you've 5mm of sheath, which is 58% of an 8.6mm diam. rope not 29%. I assume that's what he means...
Edit: I took your figure for the sheath (which I shouldn't have.) 29% of an 8.6mm rope gives a total sheath of 2.494mm which is on both 'sides' of a rope, so the amount of sheath you wear through before hitting the core is actually half that ie about 1.25mm.
Post edited at 16:03
In reply to RyanOsborne:
my calcs, assuming that 29% sheath is by volume (so calculated by cross sectional area) not weight/diameter or other measure, id get 4.04 mm diameter core on a 8.5 mm rope with 29% sheath.
sorry edit, 7.16 diameter core so only a tiny thin core.
This result sounds dubious so I'm guessing the % core is just by diameter which gives a 6.03 mm core.
my calcs, assuming that 29% sheath is by volume (so calculated by cross sectional area) not weight/diameter or other measure, id get 4.04 mm diameter core on a 8.5 mm rope with 29% sheath.
sorry edit, 7.16 diameter core so only a tiny thin core.
This result sounds dubious so I'm guessing the % core is just by diameter which gives a 6.03 mm core.
Post edited at 16:19
In reply to cliff shasby:
I struggled to follow some of that but so far as I can tell you've wrecked your new rope and aren't happy about it?
Looks and sounds like it's rubbed on something sharp. If that didn't happen with your previous ropes then I guess you could yourself lucky on that front rather than unlucky with trashing the new one.
I've had a new rope trashed first time out on the grit. Very annoying but it can happen.
jk
I struggled to follow some of that but so far as I can tell you've wrecked your new rope and aren't happy about it?
Looks and sounds like it's rubbed on something sharp. If that didn't happen with your previous ropes then I guess you could yourself lucky on that front rather than unlucky with trashing the new one.
I've had a new rope trashed first time out on the grit. Very annoying but it can happen.
jk
In reply to FreshSlate:
Ah yeah, sorry, should've read:
The Corbie has a Sheath % of 29, meaning that for an 8.6mm rope the sheath is about 2.5mm thick.
For a Mammut Obsession half rope, the sheath % is 45, so for an 8.3mm rope the sheath is 3.7mm.
That means the sheath on the half rope is 1.5 times thicker than the single, despite being a thinner rope.
I guess it doesn't matter too much whether it's on both sides or on one side, it's alarming that the sheath on the skinny single is proportionally so much less than that of a half rope.
Ah yeah, sorry, should've read:
The Corbie has a Sheath % of 29, meaning that for an 8.6mm rope the sheath is about 2.5mm thick.
For a Mammut Obsession half rope, the sheath % is 45, so for an 8.3mm rope the sheath is 3.7mm.
That means the sheath on the half rope is 1.5 times thicker than the single, despite being a thinner rope.
I guess it doesn't matter too much whether it's on both sides or on one side, it's alarming that the sheath on the skinny single is proportionally so much less than that of a half rope.
In reply to RyanOsborne:
The sheath percentage is not the percentage of the diameter of the rope it's the percentage of the weight these are different calculations!
http://books.google.co.uk/books?id=OqDNaSCxR-sC&pg=PA36&lpg=PA36&dq=%22shea...
http://books.google.co.uk/books?id=Bl9GAgAAQBAJ&pg=PA8&lpg=PA8&dq=%22sheath...
The sheath percentage is not the percentage of the diameter of the rope it's the percentage of the weight these are different calculations!
http://books.google.co.uk/books?id=OqDNaSCxR-sC&pg=PA36&lpg=PA36&dq=%22shea...
http://books.google.co.uk/books?id=Bl9GAgAAQBAJ&pg=PA8&lpg=PA8&dq=%22sheath...
Post edited at 07:16
In reply to gethin_allen:
the sheath percentage is the percentage of sheath weight compared to total rope weight, see my above post.
the sheath percentage is the percentage of sheath weight compared to total rope weight, see my above post.
Post edited at 07:24
In reply to CurlyStevo:
Yep. The diameter calculation would only be correct if the density of the rope stayed completely homogenous through the diameter. Which it doesn't.
Yep. The diameter calculation would only be correct if the density of the rope stayed completely homogenous through the diameter. Which it doesn't.
In reply to mike kann:
I think you are confusing area and radius / diametre of a circle! I take your point regarding the density of the weave but even if they were homogeneous the maths is wrong.
> Yep. The diameter calculation would only be correct if the density of the rope stayed completely homogenous through the diameter. Which it doesn't.
I think you are confusing area and radius / diametre of a circle! I take your point regarding the density of the weave but even if they were homogeneous the maths is wrong.
Post edited at 08:16
In reply to mike kann:
I've just calculated the thickness of the sheath for these two ropes (this is the thickness in the radius NOT the diameter):
The Corbie is 0.67mm
The Obsession is 1.07mm
(I checked my maths using this web page and an h value of 1 http://www.calculatorsoup.com/calculators/geometry-solids/tube.php )
Of course the maths is based upon the incorrect assumption the density of the ropes in homogenous and it also doesn't account for how tightly woven the ropes are in comparison, mammut do tend to be more tightly woven than most ropes. If the mammut is more tightly woven than the elderid it would mean there is more material in each mm of sheath than the elderid too.
I've just calculated the thickness of the sheath for these two ropes (this is the thickness in the radius NOT the diameter):
The Corbie is 0.67mm
The Obsession is 1.07mm
(I checked my maths using this web page and an h value of 1 http://www.calculatorsoup.com/calculators/geometry-solids/tube.php )
Of course the maths is based upon the incorrect assumption the density of the ropes in homogenous and it also doesn't account for how tightly woven the ropes are in comparison, mammut do tend to be more tightly woven than most ropes. If the mammut is more tightly woven than the elderid it would mean there is more material in each mm of sheath than the elderid too.
Post edited at 09:07
In reply to RyanOsborne:
for future reference you can do my maths like so:
take the CORE fraction (ie if its 29% sheath then core fraction is 0.71)
the radius of the CORE = sqrt(core fraction) * RADIUS of rope
sheath thickness = RADIUS of rope - radius of core
Note I do mean radius of rope NOT diameter.
for future reference you can do my maths like so:
take the CORE fraction (ie if its 29% sheath then core fraction is 0.71)
the radius of the CORE = sqrt(core fraction) * RADIUS of rope
sheath thickness = RADIUS of rope - radius of core
Note I do mean radius of rope NOT diameter.
In reply to cliff shasby:
Your first 2 pictures look like damage that has been done over an edge to me.
Your first 2 pictures look like damage that has been done over an edge to me.
In reply to cliff shasby:
Coming back to practicalities, have you tried taking the rope back to where you bought it?
(sorry if I've missed this on the thread)
Coming back to practicalities, have you tried taking the rope back to where you bought it?
(sorry if I've missed this on the thread)
In reply to Bruce Hooker:
and whoever..
No i havent,and i was mail order from a german company,i just emailed edelrid and got the expected reply.
Im really not after a replacement or anything,i just wondered what peoples opinion was and now its turned into a sheath percentage thing and although im sure this is a big part of rope durability its seems obvious at least to me there is a problem with this rope,ive had too many ropes and never seen anything like this done so easily and after it happening to toby on the first day im sure there is something more than just sheath percentage involved such as how tight the weave is or the twisted core on this rope that is adding to the already low sheath percentage.
Maybe time will tell if enough people buy this rope.
and whoever..
No i havent,and i was mail order from a german company,i just emailed edelrid and got the expected reply.
Im really not after a replacement or anything,i just wondered what peoples opinion was and now its turned into a sheath percentage thing and although im sure this is a big part of rope durability its seems obvious at least to me there is a problem with this rope,ive had too many ropes and never seen anything like this done so easily and after it happening to toby on the first day im sure there is something more than just sheath percentage involved such as how tight the weave is or the twisted core on this rope that is adding to the already low sheath percentage.
Maybe time will tell if enough people buy this rope.
Post edited at 21:34
In reply to cliff shasby:
Have you ever owned a rope with only 29% sheath before? This in incredibly low - I certainly never have (and wouldn't buy such a rope). Seeing as how well a rope wears is based on a multitude of factors I doubt you will ever pin point the exact issue (bobbin count, sheath percentage, tightness of sheath, dry treatment, precise usage etc). I personally think you are probably on to something with this rope but without standardised scientific testing its pretty much conjecture I'm afraid!
Have you ever owned a rope with only 29% sheath before? This in incredibly low - I certainly never have (and wouldn't buy such a rope). Seeing as how well a rope wears is based on a multitude of factors I doubt you will ever pin point the exact issue (bobbin count, sheath percentage, tightness of sheath, dry treatment, precise usage etc). I personally think you are probably on to something with this rope but without standardised scientific testing its pretty much conjecture I'm afraid!
Post edited at 09:59
In reply to cliff shasby:
If you like, I'm out at the friedrichafen show in july and I can go and talk to a few manufacturers about the effect of weave and sheath percentage etc...
If you like, I'm out at the friedrichafen show in july and I can go and talk to a few manufacturers about the effect of weave and sheath percentage etc...
Post edited at 12:21
In reply to mike kann:
This article is good
http://theuiaa.org/upload_area/files/1/Conference_on_nylon_and_ropes.pdf
This article is good
http://theuiaa.org/upload_area/files/1/Conference_on_nylon_and_ropes.pdf
In reply to mike kann:
ask each of them how they find the 1m which they then weigh to compare with competitors ropes.
do they stretch the rope first or just uncoil it? same question for diameters quoted no standard measure. still there is no doubt that ropes are lighter now than when I started
ask each of them how they find the 1m which they then weigh to compare with competitors ropes.
do they stretch the rope first or just uncoil it? same question for diameters quoted no standard measure. still there is no doubt that ropes are lighter now than when I started
In reply to mike kann:
yep that would be good,although i dont think edelrid will own up to making a fragile rope
yep that would be good,although i dont think edelrid will own up to making a fragile rope
In reply to cliff shasby:
Would it be possible that you can let me know which 8.6mm rope by BEAL you have that is triple rated.
The smallest triple I can find on http://www.beal-planet.com is the joker at 9.1mm
Thanks
Ashley
Would it be possible that you can let me know which 8.6mm rope by BEAL you have that is triple rated.
The smallest triple I can find on http://www.beal-planet.com is the joker at 9.1mm
Thanks
Ashley
In reply to cliff shasby:
I'm sure they wouldn't, so I'll talk to Mammut and Beal, as I'm sure they have an opinion on it, especially as they both produce skinny ropes...
I'm sure they wouldn't, so I'll talk to Mammut and Beal, as I'm sure they have an opinion on it, especially as they both produce skinny ropes...
In reply to mike kann:
Some of the more interesting points from the article:
- Abrasion resistance is more or less proportional to the amount of sheath,
- A tight sheath produces a rope, which is more rigid, has more resistance to abrasion and cutting.
- Sunlight: There is a correlation between decolourisation of the filaments and the mechanical properties: the higher the loss of colour, the higher the degradation of the mechanical properties. It seems to affect more the brilliant and "stylish" colours
- A study of dry proofed ropes from thirteen different manufacturers, using a variety of test methods, shows that only a very few ropes do indeed repel water well.
- After climbing approximately 5000 meters, the dynamic resistance of the rope is reduced to half and after an additional 6000 meters it is down to 30 %
Some of the more interesting points from the article:
- Abrasion resistance is more or less proportional to the amount of sheath,
- A tight sheath produces a rope, which is more rigid, has more resistance to abrasion and cutting.
- Sunlight: There is a correlation between decolourisation of the filaments and the mechanical properties: the higher the loss of colour, the higher the degradation of the mechanical properties. It seems to affect more the brilliant and "stylish" colours
- A study of dry proofed ropes from thirteen different manufacturers, using a variety of test methods, shows that only a very few ropes do indeed repel water well.
- After climbing approximately 5000 meters, the dynamic resistance of the rope is reduced to half and after an additional 6000 meters it is down to 30 %
In reply to CurlyStevo:
The one that surprised me the most out of that lot was the last point - quite a drop! Also the concept that a rope that's wet has the same strength as a dry rope are 70-80 degs C is pretty scary...
The one that surprised me the most out of that lot was the last point - quite a drop! Also the concept that a rope that's wet has the same strength as a dry rope are 70-80 degs C is pretty scary...
In reply to mike kann:
Yeah so old ropes may not break- but they may damage you / pull the gear out more easily!
Yeah so old ropes may not break- but they may damage you / pull the gear out more easily!
In reply to mike kann:
Absorption of water effectively reduces the glass transition temperature of nylon, which gives a similar effect on the mechanical properties as heating it.
The water repellency issue is a slow burner, the UIAA are working on a new test for their rope standard at the moment.
Absorption of water effectively reduces the glass transition temperature of nylon, which gives a similar effect on the mechanical properties as heating it.
The water repellency issue is a slow burner, the UIAA are working on a new test for their rope standard at the moment.
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