Carabiner Gate Openings Explained

What is a carabiners gate opening?

Gate opening refers to the distance between a carabiner’s nose and the fully open gate.

The larger the gate opening the more rope/webbing/gear you can clip into it. It is also associated with easier clipping.

Although it’s tempting to assume that a large gate opening is better, gate opening alone does not guarantee a superior carabiner. A larger gate opening signifies the potential for the carabiner to be easier to clip and hold a lot of gear, but this could easily be thwarted by the angle of the nose, the width of the basket, or the usability of the gate (i.e. ease to hold open, how your finger(s) fit).

How is gate opening measured:

To measure gate opening accurately, manufacturers use a metal pin of a precise millimeter diameter. This pin needs to be able to pass through the narrowest area of the gate opening.

There is no minimum requirement for gate openings. In fact, there is no governing body certifying the accuracy of reported gate openings since gate opening is not a required measurement to report.

For example, Mammut is one of the few brands that does not publicly report their carabiner gate openings. The gate openings for Mammut carabiners on WeighMyRack were added thanks to the US Mammut distribution center who measured the openings using calipers / a ruler. This is a less accurate measurement than using a metal pin but gives a reasonable estimate.

Range

12 mm – 33 mm is the typical range covering most climbing carabiners. Note: Even the smallest and lightest certified climbing carabiner, Edelrid’s Nineteen G, has a 17 mm gate opening.

Although the size and shape of a carabiner determine the gate range, we were surprised to find the average gate opening of each shape differed by only 2.4mm and the difference in the mode (most common gate opening) between shapes to be only 2 mm.

 

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Shape	Range	Mode (most common)	Median	Average
Oval	12 mm – 27 mm	22 mm	20 mm	20.1 mm
Pear / HMS	15 mm – 32 mm	24 mm	23 mm	22.5 mm
D	15 mm – 33 mm	22 mm	22 mm	22 mm
Offset D	14 mm – 33 mm	22 mm	22 mm	21.9 mm

*Numerical data was created from all the carabiners available on WeighMyRack in spring 2015.

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It makes sense that oval carabiners have the smallest gate opening as they were the first carabiner shape and future carabiner designs prioritized a larger gate opening in addition to lower weight and greater strength.

If we dive further into the results we can find more significant and compelling variation. Interestingly, we found the biggest differences in gate openings to be found when comparing bent gate to straight gate carabiners.

 

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Shape	Mode (most common)	Median	Average
Bent, Offset D	25 mm	24 mm	23.7 mm
Straight, Offset D	17 mm	21 mm	21. 1 mm

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Weight vs Gate Opening

There is no strong correlation between weight and gate opening although it is an interesting graph to look at. Some of the lightest carabiners have the largest gate openings. This is most likely because the reduced size of the light carabiners demands usability to be integrated in all areas including gate opening. A majority of the small light-weight carabiners are also hot-forged which allows the manufacturers to move metal around easier and create more optimal shapes.

The graph below contains the lightest 175 carabiners and you’ll notice many of the bent gates are represented by spikes on the chart.

We only graphed the lightest 175 carabiners due to Google Graphs limits for this chart type. If you super want to geek out, we made this same graph separating out the non-locking carabiners into these categories: wire gates, solid gates, straight gates, and bent gates.

 

What is the best gate opening?

Good question. It’s impossible to choose the best carabiner based on gate opening only. The answer will change depending on how you’ll use the carabiner. What matters most is how many items (and the size of items) you want to easily fit into the carabiner.

 

general guidelines

 

top of your quickdraw a straight gate is the standard here, and 17 mm – 22 mm is great

bottom of your quickdraw pick a bent gate that has a 23 mm – 26 mm gate opening

 

an anchor carabiner that needs to hold multiple pieces of gear/webbing: 19 mm+

 

 

The combination of gate opening and basket size are the two most significant factors when determining how much gear you can effectively get into a carabiner.

The relationship between basket size and gate opening also impact the technique required to clip the carabiner. If the basket and gate opening are too small, it may not be possible to clip with a full finger(s) in the basket because your fingers will get in the way of the rope sliding into the carabiner.

Bottom Line

Gate opening is less important than how the carabiner feels in your hand and how you can operate the carabiner in a clipping situation. This is because the body shape, nose design, and shape of the basket can completely change the feel and usability.

That being said, you will want a larger gate opening if you want to use the carabiner to hold lots of webbing or rope, such as in an anchor situation. For anchors, a small gate opening can slow you down and become a source of intense frustration if your systems aren’t highly refined. Clearance is king.

Adding bias towards a larger gate opening is a fantastic option once you’ve narrowed down your choice to a few similar carabiners and need to determine which one is the best.