Carabiners

Although commonly found in everyday life, the carabiner’s  true functionality is on full display during a variety of outdoor sports. Generally speaking, the carabiner is a coupling link with a safety closure, meaning it’s basically a tool that’s designed to keep you safe, consisting of a curved body with a straight or curved bar known as the gate that opens and closes.

How to Choose Carabiners

Different climbing tasks require different kinds of carabiners. To choose and use them properly, you must first understand the differences between them. There are three main areas to consider: Shape / Gate Type / Size / Weight / Strength. Once you understand the differences, think about your needs. What type of climbing you do and how you’ll use the carabiner will determine what you buy.

Carabiner Shapes

D Shape

Pros:

• Strongest shape
• Larger gate opening than oval shape

Cons:

• Smaller gate opening and heavier than asymmetric D shape
• More expensive than oval shape

D-shaped carabiners are excellent for most kinds of climbing. They hold loads off-center toward the stronger, non-gated side, so a smaller, lighter D carabiner can be just as strong as a larger oval.

Asymmetric D Shape

Pros:

• Large gate opening
• Strong and light

Cons:

• More expensive than other shapes
• Not as strong as the classic D shape

By far the most popular design out there, asymmetric D carabiners (sometimes called offset D or modified D) work like regular D’s, but they’re slightly smaller at one end to further reduce weight. Asymmetric carabiners generally have larger gate openings than regular Ds, which makes clipping them even easier. But they don’t have as much inside room as similarly sized Ds or ovals. Asymmetrical Ds make up the vast majority of the carabiners that most climbers own.

Pear Shape

Pros:

• Large gate opening
• Designed specifically for belaying and rappelling

Cons:

• Heavier and more expensive than most other shapes
• Not as strong as D and asymmetric D shapes

Similar to the asymmetric D shape, pear-shaped carabiners have large gate openings to allow easy clipping of ropes, knots and gear. 

Pear-shaped carabiners are used primarily for belaying and rappelling, but also can be used at anchor points for top roping or multipitch climbing. You’ll sometimes hear these called HMS carabiners, and some are even marked with HMS on the spine. HMS indicates that the carabiner is designed with a wide, more symmetrical top that works well with a Münter hitch knot.

Oval

Pros:

• Uniform shape limits load shifting
• Hold more gear than D-shape carabiners

Cons:

• Smaller gate opening and heavier than other shapes
• Not as strong as other shapes

Oval carabiners are the original style. 

They’re versatile and affordable, though not quite as strong as other shapes. Oval carabiners have smooth, uniform top and bottom curves to limit load shifting. 

They offer more gear-holding capacity than D-shape carabiners and their symmetry permits them to be used for carabiner-brake rappels. They’re ideal for aid climbing because they center loads at their curve; runners won’t shift under load.

Carabiner Gate Types

Straight Gate Carabiners

Pros:

• Durable and easy to use
• Can feature a keylock nose for snag-free clipping

Cons:

• Heavier than wire gate

Standard straight gates are strong, durable and easy to use. 

Carabiners with straight gates are found on quickdraws and are frequently used for racking gear, such as cams and stoppers. 

As the name implies, they’re perfectly straight from pivot point to end. Like most other types, they’re spring-loaded to open easily when pushed, but close automatically when released. Some straight-gate carabiners are also keylock carabiners. A keylock carabiner has a smooth notch where the nose of the carabiner and the gate interact. This keeps the carabiner from hooking and catching on your harness gear loop, bolt hangers and other slings, any of which can be quite annoying. You’ll likely pay a little extra for this feature, but it’s a nice upgrade.

Bent Gate 

Pros:

• Make clipping the rope easy
• Durable
• Can feature a key lock for snag-free clipping

Cons:

• Heavier than wire gate

These strong, durable gates have a concave shape that makes clipping a rope quick and easy; they are generally reserved for the rope-end of quickdraws.

Like straight-gate carabiners, some bent-gate carabiners are also keylock carabiners. Bent-gate carabiners typically have an asymmetric shape.

Wiregate Carabiners

Pros:

• Lightweight
• Help reduce gate lash
• Less likely to freeze shut

Cons:

• Can be less durable than solid straight and bent gates

Wiregate carabiners use a loop of stainless steel wire for a gate, which decreases overall weight and eliminates the need for extra parts found in conventional gates. 

Wiregate designs also allow for larger gate openings. They are less likely to freeze up than other gate styles in cold, wet weather.Although wiregates don’t appear as strong as conventional styles, most are. Also, due to the lower mass in the gate itself, wiregates are less likely to vibrate open during a fall.

Locking Gate Carabiners

Pros:

• Locking gate adds security

Cons:

• Heavier than other styles

Locking carabiners have gates that can be locked in the closed position to provide extra protection against accidental gate openings. They feature either a manual (a.k.a. screw-lock) or auto-locking system.

Screw-lock gates require the user to manually screw the sleeve onto the gate to lock it.

Auto-lock carabiners automatically lock whenever the gate is closed.

Locking carabiners, though heavier then non-locking models, are the only choice for use with a belay/rappel device. You should also consider using them at belay stations and at critical protection placements. They offer a more secure attachment and enhance your peace of mind. 

Carabiner Size, Weight and Strength

Carabiner Size

Large carabiners are typically easier to handle and easier to clip (they have larger gate openings), and they can hold more gear inside. They are commonly used with belay and rappel devices. 

Smaller carabiners are lighter and take up less room on your rack, but they can be harder to clip.

Gate open clearance, provided in millimeters, is something you may want to pay attention to when looking at the size of a carabiner. This number refers to the width that the gate can open, plus the depth and shape of the bottom of the carabiner below the gate. Generally the smaller the carabiner, the less clearance it offers. Too little gate-open clearance may lead to your finger getting stuck between the gate and the carabiner body while clipping; too deep a clearance can also make the carabiner difficult to clip. 

Carabiner Weight 

In general, the less weight you carry with you as you climb, the better. But lighter carabiners are not always best. 

Super-light carabiners are often smaller, which can make them harder to use when you’re clipping the rope or a bolt. Also, lightweight carabiners often use narrower rod stock, which can mean lower gate-open strengths and shorter lifespans. Narrow carabiners can also cause more rope wear, since the narrow ends can act like edges, biting into your weighted rope as it slides past.

Carabiner Strength

Carabiners are rated for strength in three directions: lengthwise (major axis), sideways (minor axis) and while open (major axis open or “gate open”). These ratings are typically marked on the spine of the carabiner. All climbing carabiners pass UIAA and CE standards (EN 12275), which means they are plenty strong enough as long as you use them correctly. 

Here’s how you might use strength ratings: If you’ve narrowed your search to a few different carabiners that will work well for your style of climbing, look at the strength ratings as one of the final decision points. If one carabiner provides everything you need and is stronger than the others, then you might as well go with that one. Keep in mind that smaller and lighter carabiners are generally weaker than bigger, heavier ones, but not always.

A note about gate lash: The dynamics of just about any climbing fall can cause gate lash, which can reduce a carabiner’s overall strength to its open-gate strength, creating a higher likelihood that the carabiner could break. It can occur when:

• A gate’s inertia overcomes the spring tension holding it in place
• A gate collides with another object

To protect yourself against this type of carabiner failure, choose carabiners with specific gate designs (such as a wiregate) and/or stiff spring tensions. You can also opt for carabiners with locking gates and/or high gate-open strengths.

Which Carabiner To Use

Once you understand how shape, gate type, size, weight and strength affect performance, it’s helpful to think about how you’ll be using the carabiners.

Features that make a carabiner great for one type of climbing might not make it so great for another. For example, small wiregate carabiners can be great for racking gear to keep your rack light or for making lightweight trad quickdraws, but they won’t be as easy to clip as larger, heavier carabiners. 

Most experienced climbers develop a preference for carabiners of a certain size and shape, and with a certain gate type. If you’re just starting out, here are some general recommendations: 

Once you’ve narrowed down your search, it may be helpful to visit a climbing shop. Grab a few models and get a feel for how they fit in your hand, how easy they are to clip and unclip, and how smoothly the gates work. For locking carabiners, try locking and unlocking the gate a few times (with one hand). Choose models that feel good, operate smoothly and are easy to work with.

Your safety is your responsibility. No article or video can replace proper instruction and experience. Make sure you practice proper techniques and safety guidelines before you climb.