To choose the suitable carabiner, you need to understand several related properties of the carabiner before purchasing the carabiner. Otherwise, you may choose the wrong product, which will affect the mountaineering experience and even life safety.
Properties of carabiner
carabiners come in many sizes. Large mountain buckles are usually easier to handle and clamp (they have larger door openings), and they can accommodate more equipment inside. They are usually used with protection and rope devices. Smaller mountain buckles are lighter and take up less space on the rack, but they may be more challenging to grip.
When checking the dimensions of the carabiner, you may need to pay attention to the door opening clearance in mm. This number refers to the width of the door that can be opened, plus the depth and shape of the bottom of the carabiner below the door. Generally speaking, the smaller the carabiner, the smaller the clearance it provides.
Too small door opening clearance may cause fingers to get stuck between the door and the carabiner body when clamping; Too deep clearance will also make it difficult to clamp the carabiner. The ideal amount can easily clip the carabiner.
Generally speaking, the less weight you carry when climbing, the better. But lighter mountain buckles are not always the best. Ultralight mountain buckles are usually smaller, making them more challenging to use when cutting ropes or bolts. In addition, light carabiners usually use narrow pole frames, which may mean lower door opening strength and shorter service life. Narrow carabiners can also cause more rope wear because narrow ends, like edges, bite into the heavier rope as they slide.
Strength of carabiner
The strength rating of the carabiner is in three directions: longitudinal (long axis), lateral (short axis), and open (long axis open or “door open”). These grades are usually marked on the spine of the carabiners. All carabiners pass uiaa and CE standards, which means that they are strong enough as long as you use them correctly. Door opening strength and stub shaft strength are where you see the most changes.
Here are some ways you can use strength levels: if you have narrowed down your search to several different carabiners that suit your climbing style, consider strength levels as one of the final decision points. If a carabiner can provide everything you need and is more potent than other carabiners, you might as well choose that one. Remember that smaller and lighter mountain buckles are usually weaker than larger and heavier mountain buckles, but this is not always the case.
Note on door crack: almost any climbing and falling power may lead to door crack, which will reduce the overall strength of the carabiner to its opening strength, thus increasing the possibility of fracture of the carabiner. It can occur when:
The inertia of the door overcomes the spring tension that holds it in place.
A door collides with another object.
To protect yourself from the failure of such a carabiner, choose a carabiner with a specific door design (e.g., wire door) and severe spring tension. You can also select the carabiner with locking and high opening strength (REI provides the closing and opening strength levels on the product page specification tab). Seek advice from experienced REI sales personnel.