How strong is it? GEAR (Part 1)
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What's on this page?
How strong is a belay loop?
How strong is old, crusty, sun-bleached webbing?
How strong is your rope?
How strong is a rope after it’s been spiked by a crampon?
How strong is the core and sheath of a rope?
How strong is an HMS carabiner loaded on the gate side?
How strong is an edge loaded carabiner?
1 - How strong is a belay loop?
Between 20 and 30 kN
Source / testing: How NOT2, How do you know yours is safe?
We rely on this single, non-redundant point of a harness for almost everything, so it better be unquestionably strong!
UIAA ratings require a minimum strength of 15 kN. There can be wide variation depending on the age of your harness and the material, but you can count on 15 kN at a minimum.
HowNOT2 tested a bunch! The general range was between 20 and 30 kN.
(Yes, lots of Americans still remember the tragic Todd Skinner accident from 2006, where he died from a failure of his belay loop. I took a close look at that, and share some little-known details; you can read those here.)
2 -How strong is old, crusty, sun-bleached webbing?
As low as 3-ish kN, yikes!
Source / testing: HowNOT2 Youtube, “Would you rappel on this?
That tangle of rock-rat chewed, ancient rappel anchor? It can be as weak as 3-ish kN, which you can generate by bouncing a bit with just your bodyweight!
There have been at least two recent fatalities in the United States from failure of old webbing anchors. Carry some extra 6 mm cord, probably a knife, cut out old scary stuff like this and replace it with something better.
3 - How strong is your rope?
About 14 kN
Source / testing: HowNOT2, Is your figure 8 knot going to kill you?, about 7:05
Climbing ropes don’t have a strength rating like almost all your other gear, but I bet you're curious about it! Here's an approximate answer.
If you put a dynamic climbing rope that's around 9 mm around a cylindrical drum with enough friction so it doesn't have any knots, it will stretch a LOT, and break at around 20 kN.
But of course, that's not how you use a rope. A more realistic test is to take a short bit of rope, take a figure 8 on bight in each end, and break test that.
4 - How strong is a rope after it’s been spiked by a crampon?
About 11-ish kN - basically full strength!
Source / testing: HowNOT2 short video, “Crampon vs. Rope” (filmed with me at HowNOT2 world HQ in Seattle)
There you are, trudging along on a glacier climb with crampons, you're tired and getting a little bit sloppy and . . . OUCH, you step on your rope that's leading out to your partner in front of you. Is this a problem?
Fortunately, probably not. Although you might wanna mark the spot with some tape to inspect later, and consider retiring that rope.
I had a lot of fun filming this with Ryan. Because the single crampon spike did not yield dramatic results, Ryan got a little crazy with a hammer and a nail, putting multiple more spikes in the rope. Even after doing that, it was still close to full strength!
If you separate the core and sheath of a rope, how strong is each part?
If you clip four different things into a HMS masterpoint carabiner, does that weaken it?
If a carabiner is loaded across the edge of a rock, is that bad?
