A Data-Obsessed Look at the Carabiner

Illustrations by Andreas Unterschuetz
By Alison Dennis ,

Arguably the most-used piece of gear in any climber’s arsenal, the carabiner is often overlooked by data-obsessed gear junkies because of its straightforward function and design. The data-obsessed gearheads at WeighMyRack have been collecting and documenting carabiner specs for the last four years. This data represents 717 unique carabiners from the 39 international brands that manufacture and sell carabiners. Below is a snapshot of all the carabiner options available today.* Learn more at weighmyrack.com.

*Due to new products coming out and old models being retired, these numbers are constantly changing, but they won't be dramatically different.

The Nose

The design of the carabiner’s nose can either bolster your success or lead to frustration on a climb. Keylock carabiners are generally touted as the best design for snag-free clipping. The numbers above represent how many carabiner models of each type are available in the U.S.

An often-overlooked element, nose angle has a significant impact on whether the nose will catch, particularly on bolt hangers. The smoother the curve and the flatter the arc, the lower the snag potential. Although keylock carabiners— especially wiregates— are generally more expensive, you can save some bucks while reducing snagging by looking for less expensive, notched carabiners with ideal nose angles.

Shrouding (a flared nose) reduces snagging and accidental gate opening when rubbed against rock. It’s only found in wiregate carabiners, and the amount of shrouding varies widely.

717 Carabiner Options 

Auto-locking vs. screw vs. non-locking

Wire vs. solid gate

Bent vs. straight gate

Shape tally

When buying a locking carabiner, the main choice is screw-lock or auto-locking, but many manufacturers will make three versions of one locker—a screw gate, a two-stage auto-locker, and a three-stage auto-locker—so auto-lockers are more prevalent. If you look at just non-locking carabiners, the solid/wiregate split is 60/40 and bent/straight gate is 61/39.

Strength

To ensure your carabiner is strong enough to climb on, make sure it’s CE and/or UIAA certified, and made by a known climbing manufacturer. It’d be nice if there was a direct correlation between strength and durability, but the evidence so far suggests that there is none.

Major axis closed

Low: 18 kn
Avg: 24.74 kn
High: 36 kn

The strongest orientation and the way carabiners are designed to be loaded. As a result, this is the least critical strength. Most problems occur when a carabiner is weighted in a
non-ideal orientation.

Open-gate major axis

Low: 5 kn
Avg: 8.09 kn
High: 13 kn

The biner’s strength when the gate is not fully closed, which can result from gate flutter, gate shutter, or a weak (“sticky”) gate closure. Notice the huge reduction in strength. Inspect and clean your carabiners often to prevent sticky gates.

Minor axis 

Low: 7 kn
Avg: 8.67 kn
High: 14 kn

This orientation occurs when a carabiner becomes cross-loaded, which can happen easily with a belay carabiner. Interestingly, wiregates are typically stronger than solid gates in this direction, as the wiregate bends and absorbs some of the force.

Gate Flutter

When the movement of the rope through the carabiner creates a harmonic vibration that causes the gate to slightly open and close (“fluttering”). This could be caused by a big fall when the loaded rope weights the carabiner. Gate flutter happens more dramatically with solid-gate carabiners (vs. wiregate carabiners) and is why some climbers prefer wiregate biners on the rope end of their draws.

Gate Shutter

When the gate opens (“shutters”) due to the spine of the carabiner suddenly knocking against another object (rock, other hardware, etc.).

Gate Opening

Larger gate openings are generally easier to clip and can accommodate more gear. However, the angle of the nose, the width of the basket (where the rope runs), how easy the gate is to hold open, and how your fingers fit over the gate ultimately determine the carabiner’s usability. Below is a breakdown of the carabiner-gate-opening sizes, with 22mm being the most common.

Shape

Most strength-rated carabiners are fine to use in the majority of climbing applications, but each shape has its pros and cons.

Offset D

Offset Ds are the most popular shape because they have the best strength-to-weight ratio and relatively large gate openings. Almost every carabiner, from lightweight lockers to those used on quickdraws, will be an offset D. 

Oval

This shape can flip and rotate easily, but under weight it has minimal movement, and is ideal for racking nuts, holding pulleys, and aiding. Ovals are also the best shape for rigging carabiner-brake rappels, should you drop your device.

Pear/HMS

In locking form, this is the go-to belay shape. Its large gate opening makes it easy to clip, and it will often have a rounded rope-bearing surface. Also excels as an anchor power-point biner, with ample room for clipping ropes, knots, and slings. 

Standard D 

The strongest shape, a standard D, when loaded, will direct most of the force to the spine. Ds usually have a small gate opening and thus have been mostly replaced by the offset D, which continues to improve in strength. 

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