Stretching/bending carabiners

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Stretching/bending carabiners

Postby nathanroser » Feb 7, 2012 1:46 pm

So on the past 2 vertical caves I've been to, a fellow caver has noticed that some carabiners are stretching and bending when someone is on rope. Seems like a cause for alarm, after consulting with other cavers we know, some said it's okay and other said it's not good. The carabiners are aluminum but I'll have to check up on how old they are, any thoughts?
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Re: Stretching/bending carabiners

Postby Yahtaa » Feb 7, 2012 2:37 pm

Brand? If it is a proper load bearing carabiner that hasn't been damaged by falls or misuse I couldn't understand a standard biner stretching or bending under a normal load.
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Re: Stretching/bending carabiners

Postby NZcaver » Feb 7, 2012 2:51 pm

muddyface wrote:So on the past 2 vertical caves I've been to, a fellow caver has noticed that some carabiners are stretching and bending when someone is on rope. Seems like a cause for alarm, after consulting with other cavers we know, some said it's okay and other said it's not good. The carabiners are aluminum but I'll have to check up on how old they are, any thoughts?

Depends. Flexing is absolutely normal (and temporary) for aluminum carabiners under load. See this cool video posted by Scott.



But if by "stretching/bending" you're implying the carabiner permanently changes shape, that's not good. Any photos/video?

Related advice - avoid re-tightening the screw gate after you load a carabiner, because once you're off-rope the carabiner will flex back into shape and many screw gates can bind and be very tough to undo! Loading weight onto the carabiner again will help you unlock it, or get into the habit of turning the screw gate back a quarter turn whenever you lock it.
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Re: Stretching/bending carabiners

Postby mgmills » Feb 7, 2012 3:01 pm

muddyface wrote:So on the past 2 vertical caves I've been to, a fellow caver has noticed that some carabiners are stretching and bending when someone is on rope. Seems like a cause for alarm, after consulting with other cavers we know, some said it's okay and other said it's not good. The carabiners are aluminum but I'll have to check up on how old they are, any thoughts?


I have on several occasions (while sitting at the top of a drop) watched carabiners flex when people were climbing on rope attached to them. It is quite disconcerting to watch this. The ones I have seen do this are all aluminum. I have never seen one fail (yet).
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Re: Stretching/bending carabiners

Postby Anonymous_Coward » Feb 7, 2012 3:06 pm

It's about as disconcerting as watching airplane wings flex up and down, but just as safe for the same reasons.
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Re: Stretching/bending carabiners

Postby Amazingracer » Feb 7, 2012 3:36 pm

Anonymous_Coward wrote:It's about as disconcerting as watching airplane wings flex up and down, but just as safe for the same reasons.


^ This.
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Re: Stretching/bending carabiners

Postby gdstorrick » Feb 7, 2012 6:33 pm

Post deleted.
Last edited by gdstorrick on Jul 8, 2012 5:13 am, edited 1 time in total.
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Re: Stretching/bending carabiners

Postby lee.davis » Feb 7, 2012 8:27 pm

Hey Nate,

I'm guessing these are the petzl oks. Abbe and I watched them flex at the top of McFails at NRO...kind of fun, but pretty normal.

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Re: Stretching/bending carabiners

Postby mgmills » Feb 7, 2012 8:32 pm

Anonymous_Coward wrote:It's about as disconcerting as watching airplane wings flex up and down, but just as safe for the same reasons.


I know this is off topic but I try never to sit behind the wings. If I'm in front of them I don't see them flexing.
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Re: Stretching/bending carabiners

Postby Chads93GT » Feb 7, 2012 10:09 pm

Every biner i own flexes. Black diamond. Petzl. Omega. Mammut. You name it. They flex.
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Re: Stretching/bending carabiners

Postby nathanroser » Feb 7, 2012 10:39 pm

Thanks for everything, they always immediately go back to their normal shape so it looks like it's the normal stuff that's supposed to happen. Now it just seems strange I didn't hear about it or notice it until after going down and up about a dozen or so different drops with bolt rigging. Add that to the list of apparently terrifying but not dangerous things I can tell the newbies who go with me.
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Re: Stretching/bending carabiners

Postby Chads93GT » Feb 7, 2012 11:03 pm

You will be better of not pointing that out till someone has gotten very
Comfortable on rope. Stressing newbies out can turn a high anxiety situation
Into a disaster. I only point those kinds of things out to people who
Have got past the fear of being on rope.
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Re: Stretching/bending carabiners

Postby Stridergdm » Feb 8, 2012 8:21 am

Chads93GT wrote:You will be better of not pointing that out till someone has gotten very
Comfortable on rope. Stressing newbies out can turn a high anxiety situation
Into a disaster. I only point those kinds of things out to people who
Have got past the fear of being on rope.



Great. Next you'll be telling me the ROPE stretches too!


:-)
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Re: Stretching/bending carabiners

Postby Chads93GT » Feb 8, 2012 9:28 am

Lol. I just remember telling someone on rope at mystery falls that the "caribiners were streaching open and closed." Needless to say......there is no really easy way to word that to someone on rope without putting the fear of god in them, its best to show someone when someone else is on rope and say check this out, this is normal by the way, lol.
talk about someone freaking out.l
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Re: Stretching/bending carabiners

Postby Anonymous_Coward » Feb 8, 2012 9:59 am

I NEVER noticed this phenomenon until this past November, waiting at the top of a drop in Iliad-Odyssey Cave. Since then, I have noticed it just about every time someone is jugging on a rope that is attached to a bolt with an aluminum carabiner. The Petzl OK's seem to have the most noticeable flex of any of my biners.
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