By Morgan Cvetkovic-Jones
Just like climbers, carabiners come in all shapes, sizes and strengths. With a multitude of options choosing the right carabiner for the job can seem overwhelming. Here we broad brush through the reasons behind each design and outline which carabiner(s) you will need for your rock climbing requirements.
All carabiners (often referred to as krabs) were once oval in shape, taking inspiration from a chain link, incorporating an opening mechanism or gate. As climbers and engineers realised that modifications to this once ubiquitous design allowed for obvious improvements - weight saving, improved usability and strength gains - a variety of designs and construction methods emerged, each tailored to create carabiners perfectly honed to their specific niche.
Asymmetric D- The Asymmetric D is the most common shape and features a large gate opening and focusses the load towards its robust back-bar or spine. The taper at the base further concentrates the load and helps reduce weight, whilst the wider, upper part provides the larger gate opening making it easier to clip. This multi-purpose shape can come with a locking, straight, bent or wire gate.
- Sport climbing quickdraws (wire, bent or straight gate)
- Trad climbing quickdraws (wire gate)
- Racking gear, to harness or gear sling
- Building belays and anchor systems
Pear Shaped (HMS) - The pear shaped (or ‘HMS’) krab combines the wider gate opening and rope focusing features of the Asymmetric D with the more symmetrical shape of an Oval carabiner. The body/spine is often more cylindrical in profile. These features make the HMS carabiner THE only choice for use with tuber style belay devices (Black Diamond ATC, Petzl Verso etc.), as the rope is always at the optimal angle, free flowing without the possibility of cinching in a tighter angle - possible when used with a Asymmetric D. Finally, the broader top of the HMS makes it ideal for use in rigging situations - attaching multiple knots, hitches and ropes - and guide mode applications (belaying multiple seconds).
- Top rope anchors
- Multipitch anchors
Oval - The uniformity of the oval shape, make it the carabiner of choice for use with pulleys. It also keeps loads centred (helping avoid cross loading) whilst providing ample space for racking gear on your harness. The freedom of movement afforded by the oval’s curved and spacious design makes it the perfect Petzl Gri-Gri belaying companion – affording the device lots of room to move, avoiding it getting snagged or cross loaded in the angular shape of other krab styles.
- Aid climbing
- Big walling and pulley system set up
- Racking gear, to harness or gear sling (Particularly handy when racking and selecting nuts)
- Belay devices which do not directly interact with the rope.
Lockstock and one Screwgate BarrelSome carabiners feature a locking mechanism to avoid the gate opening accidentally. A locking gate is essentially used in any scenario where we are solely dependent on a singular point of protection for ours/our climber’s safety. ‘Locking’ gates can be a manual screwgate or an auto-locking (spring-loaded) screwgate and should always be used when:
- Top rope/seconding anchor systems
Why wouldn’t I lock it?
Whilst providing more security, a locking carabiner isn’t the lightest or easiest carabiner to get a rope into, hence why we don’t use them on things like quickdraws. Non-locking carabiners come with 3 different types of gate mechanism. All 3 will do a the same job but here are the finer details:
- Straight Gate: The ‘all-rounder’, combining optimal strength with an easy opening for your rope and gear.
- Bent Gate: The curve-like bend in the gate makes it even easier to clip with a rope, particularly when climbing and only one hand is free.
- Wire Gate: The most streamlined of the bunch. Lightweight wire gates are perfect for when every gram counts. They are also less likely to "bounce" open when inadvertently banged against a rock face by the rope, a useful and little known fact.
Basic construction info: Hot Forged or Cold Forged?
The two fundamental construction methods and both still widely used. Cold forging is the original method; whereby the body of the carabiner is simply bent to shape from an alloy rod of the correct length and diameter. This is then polished and fitted with a gate. Hot forging is a refined version of the same method; whereby the rod is first heated in a forge then bent to shape whilst semi-molten. This means the molecular structure of the metal retains more strength (particular at the angles) once cooled. Some carabiners are also pressed/shaved while the spine is still hot to achieve an "I-Beam" construction- this retains the strength but allows for further weight saving.
Primarily done for aesthetic reasons, anodising is an electrolytic process for producing a coloured oxide coating on the metal. That being said, it does also help with rope flow and protecting the carabiner from external chemical attack - e.g. sea salt when coastal climbing.
Before you go, here’s a final tip...
When looking for your first carabiners, don’t get too bogged down with their strength and Newton ratings. All carabiners are meticulously tested before going on sale. You should only look at strength ratings if you really can’t decide between two different models. Oh, and be absolutely sure that the krab you’re purchasing is specifically designed for climbing and not a keyring or dog chain.