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What is the lowest rope thickness deemed safe for climbing? Like why should I buy a 10mm rope when I can buy a 7mm rope and save on storage and weight? Are lower thickness ropes more used for gear hauling? If so then what is the minimum thickness deemed suitable for climbers? Obviously this would depend on the weight of the climber, but for an average 10 stone man, what is the lowest thickness rope he could use without compromising his safety? Is there some kind of reccomended rope thickness to weight guide available?
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In reply to saturn:
Here's some info about EN892 ropes: https://www.thebmc.co.uk/rope-markings-explained
In reply to saturn:
Ropes are all tested and rated. The label on the rope tells you its characteristics. Basically, there’s a balance to be found between weight, durability & stretchy-ness.
Further reading… https://www.vertical-addiction.com/us/blogs/blog/climbing-rope-specs/
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In reply to saturn:
> What is the lowest rope thickness deemed safe for climbing? Like why should I buy a 10mm rope when I can buy a 7mm rope and save on storage and weight?
Thin ropes will require different devices and/or techniques for safe belaying and abseiling. They are also more likely to be cut through over an edge in a fall.
Post edited at 23:15
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In reply to saturn:
Many, many years ago circa 1971 I got talking to a sales rep from Edelrid. He said that they could make climbing ropes as thin as 5 mm strong enough to hold a falling leader but did not produce them because they thought no one would trust them.
Personally I find 7mm scary enough and would not want to go below that. Apart from anything else handling could be difficult.
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In reply to Gaston Rubberpants:
For a single rope anything under 9 gives me the willies.
That said, anything above 10 feels like a bloody cable car cable.
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In reply to Iamgregp:
> For a single rope anything under 9 gives me the willies.
Years ago, when skinny ropes were a novelty, I partnered up with someone to do Central Pillar (E2 5b). I had my 9mm and he had the whatever-it-was bit of string. It definitely put the willies up me, especially since I had to lead all the hardest bits.
In reply to saturn:
I like thicker ropes as they are easier to control when lowering or holding some of my more "well built" partners.
I've witness some very bad rope burns with people falling on thinner ropes.
It all depends on what you are using them for and what type of climbing. Personally, the reduction in carry weight isn't worth the extra faff/effort of using them.
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In reply to Cobra_Head:
Indeed, having done a dash along the cuillins, my partner wasn't happy down climbing so much, we took a 6mm primarily to ab into TD gap (happy to solo the climbing pitches). It was as expected extremely stretchy, impossible to hold without an additional redirection through a karabiner and you have to be very mindful of sharp edges.
Normal climbing, less than 9mm regardless of strength etc.. isn't so easy to handle. Any weight saving is likely offset by annoyance.
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In reply to Iamgregp:
How much do you weigh?
In reply to saturn:
Normally around 10 and a half stone.
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In reply to saturn:
'Obviously this would depend on the weight of the climber'
I'm going to take this and your other recent posts at face value, that you are new to climbing and want to do so safely.
Before even adressing your point/question I'm going to implore you to get actual experience with someone who knows what their doing, join a club, do a course, befriend a crusty old traddie at your local wall etc.
OK to the point, I'm going to be harsh here but based on your posts you are allowing some serious misunderstandings to affect you thinking, the quote above is an example.
The weight of the climber is effectivly irrelevent once falling is involved the distance fallen combined with the amount of rope in the system and the elasticity of the rope is what really matters (google 'fall factor'). There is no suitable rope for the weight of the climber consideration to be made.
Any rope that is a dynamic climbing rope from a reputable maker with the correct UIAA, CE etc marks sold as a single rope (look for a circle with a 1 in it) will be strong enough.
The issue with smaller diameter ropes (rated as dynamic single climbing ropes) is not that they will break, even if you have been on the pies, climbing ropes don't 'break'. However ropes do get cut running over edges etc and a thicker rope with more sheath will typically be less likely too. Thicker ropes tend to last longer generally, usually can take more bigger falls before getting knackered and very importantly are much easier to handle. Belaying and descending on thin ropes requires more skill, experience and careful selection of belay device etc.
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In reply to Cobra_Head:
Chanel No.5 and a smile x
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In reply to NBR:
Very good post. Good on you for explaining all that so clearly.
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In reply to saturn:
When nylon climbing ropes first came into use in the late 40s the principal criterion in deciding the size of these hawser-laid ropes was the minimum diameter that could be adequately gripped for a waist belay. This was determined to be one and three-eighths inches circumference, which was sold as 'No. 4 nylon'. This translated to 11mm diameter and remained the standard even after kernmantel 'Perlon' ropes appeared around 1960. Despite this, thinner 'No.3 Nylon' was sometimes used. 'No.2' was always used as a double, mostly for aid climbing.
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In reply to Andy Long:
I remember the old no.1 line still kicking around military circles in the 90s. Braided Terylene ropes too(near zero stretch, used for rigging and caving). Scary how weak some were compared to modern stuff.
In reply to NBR:
> 'Obviously this would depend on the weight of the climber'
> The weight of the climber is effectivly irrelevent once falling is involved the distance fallen combined with the amount of rope in the system and the elasticity of the rope is what really matters (google 'fall factor'). There is no suitable rope for the weight of the climber consideration to be made.
The weight of the climber is one of the key factors
https://web.mit.edu/sp255/www/reference_vault/ITRS_02_force_eqn_analysis.pd...
graph shown below.
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In reply to timparkin:
I'm going to stand by my assertion that in real life the weight of the climber is effectivly irrelevent when selecting rope diameter, from the perspective of is the rope strong enough (assuming its a dymamic rope rated as a single).
Edit added the bold bit for clarity.
Post edited at 09:16
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In reply to timparkin:
> The weight of the climber is one of the key factors
> graph shown below.
>
That's a strange graph. Apart from the fact that any scientific (even American) study would, I hope, be using kg and Newtons, it doesn't say what's being measured. Is it the maximum force that can be generated in a real fall (because the elasticity in the rope will prevent this being exceeded)? As others have said, I don't think this depends on the weight of the climber - a heavier climber will cause more extension, so slow the deceleration, and therefore not increase the maximum load, at least not linearly as the graph shows. Or is it showing the tension in the rope if the load is hung statically? This would produce a linear graph, but is surely irrelevant to a fall in a climbing situation.
Where I think the climber's weight does enter into the equation is when we're considering abrasion over rough edges - which, as others have said, is the main reason for rope failures (rare as they are). There was a fine video illustrating this on here a few years ago.
Martin
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In reply to timparkin:
> graph shown below.
Doesn't seem to tally with the paper you linked: your graph shows a linear relationship between mass and force; looks more like 'weight' to me. The paper shows the square root(weight) term of the rope response.
The Attaway paper they reference is the best I've found on the topic.
In reply to Martin Hore:
No. The force would be proportional to the weight of the falling object. It's just that most equations presume an 80kg weight. If you look at the Bath copy of the multi pitch climbing book, they have a modifier 'scaling factor' for the force. Short link below but it gives the force as directly proportional to weight.
> That's a strange graph. Apart from the fact that any scientific (even American) study would, I hope, be using kg and Newtons, it doesn't say what's being measured.
Well it depends on context. The US climbing community tends to use imperial measurements (and bizarrely lb as force) This is from the International Technical Rescue Symposium hosted via MIT so I'm giving them some credit.
> Is it the maximum force that can be generated in a real fall (because the elasticity in the rope will prevent this being exceeded)?
So you're saying the weight of the climber doesn't matter as they're unlikely to break the rope - well, yeah. Unless it does matter.
> As others have said, I don't think this depends on the weight of the climber - a heavier climber will cause more extension, so slow the deceleration, and therefore not increase the maximum load, at least not linearly as the graph shows. Or is it showing the tension in the rope if the load is hung statically? This would produce a linear graph, but is surely irrelevant to a fall in a climbing situation.
No. The force would be proportional to the weight of the falling object. It's just that most equations presume an 80kg weight. If you look at the Bath copy of the multi pitch climbing book, they have a modifier 'scaling factor' for the force. Short link below but it gives the force as directly proportional to weight.
https://shorturl.at/nsyDS
Here's some more info showing UIAA standard tests giving similar results (from the Professional Association of Climbing Instructors Pty Ltd). I extracted the key sentence from this in an attached image.
https://www.paci.com.au/downloads_public/PPE/04_HeavyClimbersBeware.pdf
However, I agree that the weight isn't really a consideration in terms of the rope breaking in normal use.
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In reply to captain paranoia:
> Doesn't seem to tally with the paper you linked: your graph shows a linear relationship between mass and force; looks more like 'weight' to me. The paper shows the square root(weight) term of the rope response.
Yeah, the US has a strange relationship with force where they often use weight and force interchangeably in some contexts.. However ....
> The Attaway paper they reference is the best I've found on the topic.
I agree - it's great. It also states that the force in a fall is directly proportional to the weight of the climber. See attached extract
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In reply to timparkin:
Thanks Tim. Lots of solid research to get my head round when I have a few spare hours, and if I can get my head round Attaway's units - honestly, lbs, feet, kg and newtons all in the same paper - what did the Americans ever do for us!
My sister in law's partner teaches high school physics in Boston MA. I asked him once what units he teaches in - the answer was SI - so there may be some hope for the future.
Martin
In reply to Martin Hore:
> Thanks Tim. Lots of solid research to get my head round when I have a few spare hours, and if I can get my head round Attaway's units - honestly, lbs, feet, kg and newtons all in the same paper - what did the Americans ever do for us!
> My sister in law's partner teaches high school physics in Boston MA. I asked him once what units he teaches in - the answer was SI - so there may be some hope for the future.
America still has two different specifications for the foot, which has caused many issues in the past (as you can imagine) and has only recently resolved to just use the international inch.
https://oceanservice.noaa.gov/geodesy/international-foot.html
Cam sizes in the US are supposedly in inches too (but they're not, must be using the 'cam standard inch')
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In reply to timparkin:
One should note the standard uses an 80kg mass, this is considered the solid-mass equivalent of a 100kg climber in a sit harness.
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In reply to timparkin:
> It also states that the force in a fall is directly proportional to the weight of the climber
I never said it wasn't. What I did say was that your graph seemed entirely linear (i.e. F=ma, where a is fixed; g, perhaps?), which did not tally with the formula or graphs in the paper you linked.
Looking more closely at the figures in the table, it's not quite linear. Maybe adding further weight will illustrate the effect of the non-linear term better.
Post edited at 15:57
In reply to timparkin:
Edelrid - weight and cut resistance video
In reply to jimtitt:
> One should note the standard uses an 80kg mass, this is considered the solid-mass equivalent of a 100kg climber in a sit harness.
By standard, I meant a standard UIAA tests with weights greater than 80kg. I didn't realise that the UIAA 80kg was meant to simulate a 100kg climber.. interesting - a poor substitute for a floppy body though.
in paper "Weber, C.; Hudson, S. UIAA Dynamic Rope Drop Testing Results with Loads Greater than 80 kg; International Technical Rescue Symposium: Fort Collins, CO, USA, 1999"
In reply to jimtitt:
> One should note the standard uses an 80kg mass, this is considered the solid-mass equivalent of a 100kg climber in a sit harness.
p.s. I love the "Hang 'em High" paper which I've only just discovered... I'm sure you've seen it though
https://mra.org/wp-content/uploads/2016/05/Hang_Em_High_Final.pdf
and it has a better graph which includes weight
Post edited at 19:53
In reply to timparkin:
It was the (rounded slightly for practicality) value found by experimentation using live volounteers by Troll if my information is correct. The intention behind that and most of the other standards is not to equal "real life" but produce a test which ensures equipment survives real usage.
It's also worth viewing the numerous papers on the subject by bearing in mind the rope in itself is only one part of the picture, what happens at the other end is of more importance, that is, doubling for example the fallers weight is unlikey to be accompanied by a doubling of the force the belayer can provide.
In reply to jimtitt:
> It was the (rounded slightly for practicality) value found by experimentation using live volounteers by Troll if my information is correct. The intention behind that and most of the other standards is not to equal "real life" but produce a test which ensures equipment survives real usage.
> It's also worth viewing the numerous papers on the subject by bearing in mind the rope in itself is only one part of the picture, what happens at the other end is of more importance, that is, doubling for example the fallers weight is unlikey to be accompanied by a doubling of the force the belayer can provide.
Absolutely - I've read your work on the matter and looked at some finite element modelling of ropes (which I'm not sure worked that well). thanks for responding.
In reply to jimtitt:
> One should note the standard uses an 80kg mass, this is considered the solid-mass equivalent of a 100kg climber in a sit harness.
is this because being non-rigid, the deformation/movement in/of a climber's body absorbs some of the energy?
[Non engineer trying to at least get some grasp of all this technical stuff]
In reply to Michael Hood:
Well it will reduce the impact force for sure (how much energy is absorbed is anyones guess), it's a common thing in testing to produce an equivalent to soft (particularly living) objects for repeatability and practicality, people to test crumple zones in cars for example are going to be hard to find!
In reply to Michael Hood:
Well it will reduce the impact force for sure (how much energy is absorbed is anyones guess), it's a common thing in testing to produce an equivalent to soft (particularly living) objects for repeatability and practicality, people to test crumple zones in cars for example are going to be hard to find!
In reply to Michael Hood:
In reply to jimtitt:
> is this because being non-rigid, the deformation/movement in/of a climber's body absorbs some of the energy?
It can be a really big influence on small falls on static ropes. The DMM video shows a small fall on a static sling breaking the sling and measured 16kn but How Not To bravely (stupidly) took some falls in similar conditions (factor 1, sliding X, 82kg) and got 2.5kn
DMM static mass, one leg fail, factor one = 16kn
Ryan Jenks, one leg fail (not Ryan's), factor one = 2.5kn
So the human body absorbs lots of force in all it's wobbly bits..
Here's Ryan Jenk's results in tabular from from this video. youtube.com/watch?v=nr3YBDnOI8Q&
What did you think of Ryan's human body experiment Jim?
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In reply to saturn:
Personally, I'm old school and prefer 9mm double ropes, or 11mm single ropes (although I think my current single is actually 10.5mm) - as much for the handling and compatibilty with my current belay devices as anything. If I went any thinner, I'd need to buy more gear that I don't really need.
I do a lot with Scouts and their rules state that I have to use single ropes with a minimum 10mm diameter, despite the weight of most of the kids climbing being <50kg, the younger ones quite a lot less. Other ropes are allowed in certain circumstances (abseiling, rigging, etc), but must also be minimum 10mm, which can cause some issues with the very light ones abseiling!
Post edited at 16:12
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In reply to timparkin:
Not the sort of thing I think about really.
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In reply to saturn:
Wow, is this roll bread (troll's bait thread) still tricking people into replying. At least OP is banned
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In reply to CantClimbTom:
He's merely a catalyst - the conversation moved to something interesting (to me anyway)
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In reply to Iamgregp:
ha ha, nice one.
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