Ascender Safety 101

       Ascending Rappel Ropes 101

       Autoblock Misuse (ATC-Guide)

       Avalanche Safety

       Belay School - Why Dynamic Matters

       Can A Hot Belay Device Melt My Slings?

       Carabiner Off-Axis and Tri/Quad-Axial Loading

       Choosing the Right Carabiner

       Common Belay Screw-ups

       Connecting Two Slings Together

       Daisy Chain Dangers

       Dangers of Rope Worn Carabiners

       Dangers of Worn Lowering Anchors

       Do Ropes Need to Rest Between Falls

       Draws in a Gym

       Extending a Cam Sling

       Fall Factors Explained

       Full Strength Haul Loops

       Gear Doesn't Last Forever—Crampons

       Gear Doesn't Last Forever—Ice Tool Picks

       Gear Doesn't Last Forever—Slings & Draws

       Girth Hitching a Stopper

       How Sketchy Is a Sharp-Edged Carabiner?

       How Strong are Himalayan Fixed Lines?

       How Strong is the Spinner Leash?

       How To Belay, Part 1

       How To Extend a Rappel Device

       Knot Passing 101

       Rappelling - Climbing's Diciest Business

       Re-Slinging Cams

       Rethinking the Double-Loop Bowline

       Retiring Old Ropes

       Sharpie for Marking the Middle of a Rope?

       Sling Strength In Three Anchor Configurations

       Spectra versus Nylon

       Spotting for Bouldering

       Surviving Bad Weather on El Cap

       The Dangers of Modifying Your Gear

       The Dangers of Short Static Falls

       The Electric Harness Acid Test

       The Skinny on Super Light Ropes

       Top Roping is Not So Safe

       To Screamer Or Not To Screamer

       Via Ferrata

       Weakness of Nose-hooked Carabiners

       What is the Safest Rappel Knot?

       Worn Belay Loops and Retiring a Harness

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Climb Safe: Weakness of Nose-Hooked Carabiners

By Kolin Powick

The following article is courtesy of Black Diamond Equipment.

Nose-hooked carabiners can be cantilevered off of a bolt hanger/sling/Stopper wire. This off-axis loading causes the carabiner to be excessively torqued and to break at an extremely low load.

Carabiners are incredibly strongthey meet a minimum test of 20 kN (4496 lbf or 2039 kg) when properly loaded on their major axis with the gate closed. In an open gate scenario, carabiners still test to a minimum of 7 kN (1574 lbf or 714 kg). 

But when you test a nose-hooked carabiner, it can fail at less than 10% of its rated closed gate strength—that's less than 2 kN (500 lbf or 227 kg), a load that can be easily generated in even the smallest of climbing falls or even just a light bounce test.



Why is the carabiner's breaking strength so low when loaded in this manner? It's a combination of an open gate scenario coupled with the fact that the carabiner basket is being cantilevered off of the bolt hanger/sling/Stopper wire, meaning the load is not in line with major axis (i.e., the carabiner's spine). This off-axis loading causes the carabiner to be excessively torqued and break at an extremely low load.



Black Diamond manufactures a lot of carabiners, and therefore Black Diamond tests a lot of carabiners. We not only understand the loads at which carabiners break, but also the modes (i.e., location of breakages), depending on the way it was loaded. So it's possible to look at where a carabiner is broken and have a good idea of how it was loaded.

The photos below show typical failure locations for one style of carabiner tested in four different configurations. As you can see, a nose-hooked carabiner will most often break at the top of the spine, while open and closed gate failures typically occur at the bottom of the spine, and minor axis failures almost always occur at the gate.

[Disclaimer: All carabiners are different, and detailed analysis of the particular carabiner's geometry and failure modes is necessary in order to be able to estimate the particular loading scenario with any level of confidence.] 

Closed gate failure. Open gate failure.


















Nose hook failure. Minor axis failure.



















When a carabiner is loaded while the nose is hung-up on a bolt hanger, a leveraging open-gate scenario occurs. Carabiners are significantly weaker in this configuration—less than 10% of closed-gate strength.

How to avoid this? Always ensure that the carabiner's gate is closed and the carabiner is correctly seated.

Climb safe -


Kolin Powick (KP) is a mechanical engineer hailing from Calgary, Canada. He has over 20 years of experience in the engineering field and served as Black Diamond’s Director of Quality for over 11 years. He is currently their Climbing Category Director. If you have a technical question for KP, please email him at and he will TRY to respond.


To help make more climbers safer climbers, Rock and Ice has teamed up with Black Diamond Equipment to present the information here.

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