How strong is it? OVERVIEW
Most climbing gear is tested and rated by Official Entities such as the CE and the UIAA. This is great! It gives us confidence that gear from brand-name manufacturers is made to the highest standards.
But not everything climbers use is covered by these ratings.
What about anchor rigging and knots?
What about rated gear that's old, a bit worn, a bit abused, but still hopefully serviceable?
What about gear that may be appropriate for climbing, but may not be officially rated by these agencies?
These are important questions.
My friend Ryan Jenks from HowNOT2.com has made an entire YouTube channel and brand based on breaking and testing climbing gear. (Give his YouTube a follow if you’re not already.)
The thing is, he's almost too successful. He's done so much testing that sometimes it's difficult to find the exact topic you’re interested in.
So, I took some select tests (mostly from Ryan) and made a series of articles covering anchors, gear, and knots.
It's nowhere close to an exhaustive summary of all possible gear and rigging. It's more of a collection of Ryan's test results about which I was personally curious.
To keep things manageable, I have about 7 results on each article. As my curiosity continues (or I get submissions from Alpinesavvy fans like you) to add to this page, I will add part 2, part 3, etc…
I have links to sources and test results where appropriate.
If you have a new break test question / idea (and hopefully have a source for test results), please let me know about it and I might include it.
If you join Alpinesavvy as a Premium Member, you’re entered into monthly gear giveaways and regular discounts from Ryan’s store, hint hint.
Disclaimer: Yes, some of these test results are limited by the number of tests, to a specific manufacturer, they might be a static pull and maybe not drop tower, or vice versa, your mileage may vary, and blah-blah-blah. It's designed to give you a data point, not to apply universally to every situation. And as Ryan likes to say, this is entertainment, not science.
Basic premise #1 - What’s a kilonewton (kN?)
Let's start with the basics. A kilonewton is a metric unit of force, equal to the weight of about 100 kg or 225 pounds.
The way I like to think of it: one kN is the average weight of one NFL football player, more or less.
So, here's a visual: A skinny 8 mm dynamic sling that's rated to 22 kN can hold about 22 football players all hanging off of it at the same time! Yes, that is kind of crazy to think about and yes, most all of the gear we use is impressively strong!
Fun facts . . .
the “N” is capitalized in “kN” because it refers to the last name of Sir Isaac Newton.
There are only three countries in the world that don’t use the metric system. Myanmar, Liberia, and ‘Merica. Metric measurements are the international standard of pretty much everything, especially climbing, and that's what this ‘Merican is using.
Basic premise #2 - What's the maximum force possible in recreational climbing?
About 9 kN.
Source: Engineer and climbing book author Craig Connally, from his book, The Mountaineering Handbook.
This is a somewhat challenging question to answer, but arguably the most important when it comes to talking about the strength of our gear and systems.
If the maximum possible force that you can ever create outside is around 9 kN, to me it seems kind of silly to argue about things like, “you shouldn’t girth hitch a Dyneema sling to a carabiner, it makes it weak!”, when it turns out it actually holds about 18 kN. (Which is stronger than your rope . . . )
A few things to keep in mind . . .
This maximum force can only happen in the very rare case of a factor 2 fall onto the anchor, which 99% of climbers will never experience.
There are various ways to avoid a factor 2 fall. Probably the best one is to place solid gear as soon after the anchor as possible on a multipitch climb.
This number will probably always remain somewhat theoretical, because you can't test factor 2 falls with a real humans, because they’ll get injured.
Testing in a drop tower with a concrete weight creates forces much higher than can happen in the real world . That's largely because of the squishy human body. Learn more about that here.
Here are some realistic scenarios involving real people, tested by Petzl and HowNOT2. Spoiler: Factor one fall, maximum force about 6 kN on the top piece of gear. Here's my article on that.