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If the maximum braking force of my belay plate is 2 to 2.5 kN - typical for most modern plates, even those with teeth - why should I worry about cross-loading of my belay biner when the weakest that I use (Petzl Attache) is rated to 6 kN cross-loaded, and others are even stronger?

I accept that spinning of the biner can be mildly irritating, particularly when belaying with double ropes, but as I understand it a cross-loaded belay biner is still plenty strong enough for arresting a fall without breaking. So why the big song and dance about it?

Are people worrying about a problem that doesn't really exist? Or am I missing something?

Its more to do with the rope twisting and pressing against the gate - shearing the thin locking sleeve and releasing the bite of rope from the biner in a shock loading situation.

In reply to pacman: While i'm not up on the breaking strengths of belay plates, i'm not sure that they're especially important. The point of a belay plate is that it will be put under compression. By comparison, a belay biner is going to be loaded under tension, from the climber pulling the rope tight.

I was going to try and quote some maths, but i've realised that even if i do, the force exerted by a climber is unlikely to exceed 7kN. Despite what, why would you want to put yourself in the hands of something which is not as strong as it could be? The climber's frame of mind tends to be 'everything must be as strong as possible. If one thing sucks, how can i back it up?'

I dunno. Stop asking awkward questions.
pacman is talking about the braking force of a plate, not its breaking strength. A typical plate with a strong belayer will get up to about 4kN which is then the tension on the belay karabiner, as pacman says this is lower than the cross-loaded strength of a karabiner and heīs right in that it isnīt the biggest worry in the world.
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> Its more to do with the rope twisting and pressing against the gate - shearing the thin locking sleeve and releasing the bite of rope from the biner in a shock loading situation.
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I don't understand how that could happen to be honest
In reply to pacman: The braking force has nothing to do with the total impact force of a falling climber.

Sorry might have got that wrong, could be the biner twisting against the harness.
In reply to jimtitt: That's true. Sometimes I swear i'm losing the ability to spell. Read braking as breaking, got myself the wrong end of the stick.
In reply to pacman: If by matter, what you mean is "Is my belay carabiner in constant imminent danger of breaking due a fall occuring while it's sideways across my belay loop?"

Then quite obviously no, as I think (though I may be wrong here) that there are a grand recorded total of precisely zero failures of modern carabiners due to this while belaying. But....

I still really rate and like the BD Gridlock, soley because I like the fact that my device and biner are always perfectly lined up and working properly with no fiddling or adjusting required at inconvenient moments. So safer? Not really. Nicer? Yes, for me at least.