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frogman-
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Aug 10, 2004, 7:04 PM
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Im 117 lbs (53 kgs) and was woundering on short falls could an 8 mm rope hold me? It rated at 4.2 kn and 8 falls with 7% stretch. I looked at the Petzl fall simulator but that shows force in DaN and im not sure how those relate.
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vegastradguy
Aug 10, 2004, 7:07 PM
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the short answer: no, this is not a safe option.
use a certified single rope, all of which are 9.2mm or larger (although you would probably best be served with a rope diameter or 10.2-10.5mm if it is your first rope.)
the rope you found is probably part of a half or twin rope system and needs to be used in conjuction with another line.
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andy_reagan
Aug 10, 2004, 7:25 PM
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why use a dinky 8mm line when you could use the standard 10mm? :shock:
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jerrygarcia
Aug 10, 2004, 7:45 PM
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In reply to: why use a dinky 8mm line when you could use the standard 10mm? :shock:
Who set this standard? I use 9.2 and love them. Never heard 10mm was "standard"
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g
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Aug 10, 2004, 7:57 PM
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In reply to: In reply to: why use a dinky 8mm line when you could use the standard 10mm? :shock: Who set this standard? I use 9.2 and love them. Never heard 10mm was "standard"
Agreed, I like my smaller lines. Not as durable, but light!
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cerikpete
Aug 10, 2004, 8:54 PM
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You'd have a lot of nice dynamic accessory cord :wink:
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screamer
Aug 10, 2004, 9:53 PM
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if your beginning climbing get a 10mm or bigger, they last a bit longer.
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namascar
Aug 10, 2004, 10:08 PM
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And so will you
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gramps
Aug 10, 2004, 10:42 PM
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I've been looking at an 8mm Rando rope for ski mountaineering. Is this rope suitable for roping up and breaking cornices, or skiing on belay, where a small fall could result?
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micahmcguire
Aug 10, 2004, 11:11 PM
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for short falls I'm sure it would be fine. but it sure won't last as long. i use 8 mm rope all the time in the mountains. anyone who doesn't think they can't take the weight of a falling climber is smoking some seriously good weed, or is reegurgitating misinformed drivel.
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frogman-
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Aug 10, 2004, 11:24 PM
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In reply to: why use a dinky 8mm line when you could use the standard 10mm? :shock:
Im not goin to do serious climbs. I live in ohio so there arent any major climbing spots. Most climbs will be short 50 ft climbs.
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vegastradguy
Aug 10, 2004, 11:49 PM
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anywhere a fall could kill you is a serious climb.
you want to save $20-$40 for your life? please. go to gearexpress.com or some other place...theres always ropes on sale for $90 or so.
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coylec
Aug 10, 2004, 11:55 PM
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8mm ropes are fine, as long as you use them as intended, as twin or double ropes (check the label). So, you'll need two.
Always use ropes in accordance with their UIAA rating.
coylec
actually, it is getting a bit crowded out at the crags ...
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mcclung
Aug 10, 2004, 11:56 PM
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In reply to: In reply to: why use a dinky 8mm line when you could use the standard 10mm? :shock: well because its only 60 or 70 $ compared to a 100 or 120 $ 10mm rope. Im not goin to do serious climbs. I live in ohio so there arent any major climbing spots. Most climbs will be short 50 ft climbs.
Where did you find an 8mm for 60-70 dollars? Is this a 50 or 60m rope? or is it this mountaineering line? Double ropes are roughly the same price each as a single, except you need two. Even though half ropes are rated for bringing up a second on just one strand this is an advanced technique only really useful for multipitch trad with a party of three.
If you use a thin rope for top roping at a local crag it will wear out very quickly. Plus, it is not adequate to lead on.
If you're looking at that 30m rope, try these for comparison: short ropes. However, I would advise against a short rope because it will end up being a waste of money.
Michael
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iclimblilrocks
Aug 10, 2004, 11:57 PM
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I think that you might be talking about a haul line, SAVE THE MONEY AND GET A 10.5mm.
http://www.rei.com/...EI_SSHP_CLIMBING_TOC
get that, Its worth the extra money, think of it this way, spend 100$ or would you rather have your family spend 10,000+ on a funeral
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elliot
Aug 11, 2004, 12:18 AM
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I climb with the Beal Rando (8-mm by 30-m) for ridge traverses in the Sierra, and have confidence in it knowing that I will be using it almost exclusively for rappels with the occasional full-on belay. I weigh 150 pounds and I'm not at all worried taking a fall on it, giving its fall rating and that the most I can fall, theoretically, is 60 meters or, practically, given how I place pro and my tolerance for risk, about 30-40 feet.
My only concern with the rope used in this way is abrasion, so I am always vigilant about keeping it from sawing on rock.
Too many have said "Don't use an 8-mm." And to be sure, for cragging you ought to take a beefier rope (approaching if not exceeding 10-mm). But there [are] instances in which an 8-mm rope not only is safe, but is optimal as well.
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valeberga
Aug 11, 2004, 12:28 AM
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So the Beal Rando 8mm has these UIAA ratings on the packaging that suggest it can take actual falls. But if you look at the ends of the rope, it has the twin rope markings. Which would seem to indicate these fall ratings are for the rope in a twin system and not as a single line. Which if this is true, leads to the question, was the rope ever even tested as a single line?
I e-mail Beal with the above questions, but never got a response...
Short of it is I really don't think anyone should take vertical falls (rock climbing, ice climbing) on this rope unless it is twinned. It's fine for low-impact falls such as punching into a crevasse or sliding down an angled snowslope, but I seriously doubt it was meant to be used as a single rope for any rock climbing purposes. Well, I take that back. It's fine for following, just not leading.
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frogman-
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Aug 11, 2004, 2:59 AM
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Im actually talkin about the Beal Rando. My dad has been a rock and mountain climber for years and seems pretty confident that it will work just fine.
Im also confused about the impact ratings and fall ratings. On the rope package it has a graph.
-----------------------------------------------------------------------------
# of UIAA Falls 12
Impact Force UIAA 8.50 kn
# of factor .8/80 kg falls 5
Impact force Factor 0.8/80 kg 4.20 kn
--------------------------------------------------------------------------------
whats the difference between the different fall factors and impact forces?
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mcclung
Aug 11, 2004, 8:42 AM
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In reply to: Im actually talkin about the Beal Rando. My dad has been a rock and mountain climber for years and seems pretty confident that it will work just fine.
Off the Beal webpage: (link)
"Rando rope is dynamic in type, and exclusively for use as an aid in walking and ski-mountaineering."
"Use as a climbing or mountaineering security rope is totally forbidden."
"For mountain and icefall use.
Clipping 2 strands essential. "
In reply to: Im also confused about the impact ratings and fall ratings. On the rope package it has a graph. ----------------------------------------------------------------------------- # of UIAA Falls 12 Impact Force UIAA 8.50 kn # of factor .8/80 kg falls 5 Impact force Factor 0.8/80 kg 4.20 kn -------------------------------------------------------------------------------- whats the difference between the different fall factors and impact forces?
These are specs for a twin rope, which means the data was taken with two strands doubled. The UIAA tests are described here.
In addition to the above warnings have you consider how fast a single 8mm will wear out cragging? What about how hard it will be to belay with. It would take an skilled belayer to stop a climber on that thin a line. Anyone fitting that description won't use your rope.
Plus the Rando is short.
Michael
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atanarjuat
Aug 11, 2004, 9:20 PM
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In reply to: Im 117 lbs (53 kgs) and was woundering on short falls could an 8 mm rope hold me? It rated at 4.2 kn and 8 falls with 7% stretch. I looked at the Petzl fall simulator but that shows force in DaN and im not sure how those relate.
Just for the record, a DaN is a decaNewton=10N
1kg of mass on Earth weighs ~9.8N, which is why the DaN is such a convenient unit of force.
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robmcc
Aug 11, 2004, 9:42 PM
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Not long ago in another thread I posted that any time you're asking if it is safe to do something different than what everyone else does and your reason for doing so is to save a buck, there's a simple answer.
No.
As I said then, there are exceptions. If you have to ask, you aren't one of those exceptions. People aren't climbing on 9.X to 10.X mm ropes because they're too stupid to see this wonderful opportunity for economy that you've discovered. They're doing it because it's safe.
It's still true.
Rob
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jeffers_mz
Aug 12, 2004, 1:16 AM
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It makes no difference how far you fall. What decides whether the rope will break or not is the ratio of the distance you fall compared to the length of rope in use. This is referred to as "Fall Factor".
A two foot fall on two feet of rope tied off to an anchor will impart more stress to the rope and anchors and you than will a one hundred foot fall on two hundred feet of rope. The two foot fall described above will be more likely to break the rope and result in your death than the one hundred foot fall described above will.
You can accept this now, or you can do what I did, which was to continually challenge the concept using math and physics until I became convinced of its truth. Here's your head, here's the wall, you decide.
The rope acts as a spring, which arrests the energy of your fall over a longer period of time, reducing the peak forces imparted to the rope and the rest of the system. More rope in play equals a bigger spring. Less equals a smaller spring. More spring is better.
The theoretical maximum fall factor is 2.0, which is what would happen if you left the belay without placing any additional protection climbed a given distance above the belay, fell and were arrested that same distance below the belay. There is at least one exception to this theoretical maximum which shouldn't concern you unless you practice simul-climbing. People asking questions in this thread shouldn't simul-climb.
If the material quoted in this thread accurately reflects that distributed by Beal, then you already have your answer. If the manufacturer says no, then ignore at your own risk.
If you need a lighter alternative to a standard rope, look into a 30m 10+mm rope available at many distributors who sell them off the ends of big drums when there isn't enough left to make a standard length.
I have a 30m 10.2mm PMI, and it is very handy for short rappels, and for short ascents, namely those that fall between the 40' topo lines on bushwhacks. It weighs 4.7 pounds and cost me $50 delivered. It showed up 38m long, I cut it to 30m and use the 8m scrap for practice and as a super cordalette if needed.
If all you plan to do is rappelling or ascending, 8mm cord will be adequate. The kinetic energy a rope has to absorb to stop your descent is related to your weight and your velocity times your velocity. In proper rappelling you don't get moving fast enough for that velocity squared factor to strain the rope. In falling, you do.
In the bigger picture I like to use prior planning, including much beyond rope selection, to minimize risk. I try to avoid planning around calculated risk. It ails my karma, and when unexpected risk shows up, and in the mountains it always does, I need all the karma I can get. Being able to cut it close has its uses beyond any doubt, but I like to save the practice for when it is unavoidable, not throw it away in advance by planning it into a trip.
I'm not trying to abuse you, but I think you asked the wrong question. Some kind of doubt arose in your mind, which led to you posing the question you asked here. This is my opinion only, though I expect others here will support it, but when doubt arises in a person's mind, I think they will live longer and happier lives not by asking if they can get away with a calculated risk, but instead by asking, how can the risk be reduced or eliminated. Dead is dead, no second chances. Alive but failed gives you all the second chances you care to attempt.
Which do you prefer?
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gramps
Aug 15, 2004, 8:51 PM
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Well, I went ahead and bought the Rando. It was $40 on shoreline mtn, so I figure my investment isn't that great. I do enough backcountry skiing where I might be doing short rappels, or cornice cutting, or even a little skiing on belay, that I think it will be worthwhile to have a short, light rope. Thanks to everyone for making the ropes limitations clear. I'll be sure not to trust it to protect a severe fall.
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