RRC Archives

Instead of studying I was poking around online and came across something confusing.

www.climbing.com/techtips/trad/tttrad234/

• Never catch and weight the nose of a biner on a sling, hanger, or cable. This can cause it to break under body weight, as there is a tremendous amount of leverage on the spine of the biner.

I'm interpreting this as meaning that the nose of the biner shouldn't be facing the gear. But I don't get it. How is the direction of the biner going to change the forces on the spine? Aren't you pulling in straight lines along the long axis of the biner (assuming you're not crossloaded or something)? What about quickdraws pulling on hangers? Please educate a poor fool who doesn't understand fisiks.

Rick? Are you here?

Sounds like they are trying to discribe the notch where the gate closes catching on something with the spine against the rock?

Wes

If you catch on the nose, you are not quite cross-loading it, but you are not loading along it's strongest axis either. It's a diagonal load. And obviously, if a sling or whatever is stuck on the nose, the gate will not be closed, so it loses that strength as well. I've seen a person snap a biner in half that way.

As for the leverage, the force is normally applied in the hook in the end, closer to the spine (on a D shaped biner) and resisted through the spine and the gate. This is only a tension load. Loaded like you've described, the load is applied at the nose and resisted only through the spine, so there is both a tension and a torque.

I think they're pretty much talking about using a beaner as a hook. That's obviously a no-no.

Hmm. Yep. Makes a lot more sense when you look at it that way.

I couldn't resist.
I rigged the biner as illustrated here,



then a very moderate bounce test yielded this,

note to self: don't do that.

Also, don't rappel from belt loops on your blue jeans. I did this while night climbing once. I thought it was my belay loop. I'm surprised it held me for the entire descent. I noticed my error after touching down on the ground. It ripped off easily with a sharp tug.

note to self: don't do that either.