The Mammut Belay Chain is a beefy personal tether composed of interlocking sewn loops. Along with climbing guides Brian Shelton and Jim Waugh, I tested the Mammut tether on over 100 pitches at the Garden of the Gods, Shelf Road, Pikes Peak, Turkey Rocks and other central Colorado crags. We used the chain in a wide variety of scenarios, including clipping onto bolt anchors, gear anchors, equalized master points at belays, and anchors for multiple rappels.
The links on the Mammut chain are of two different sizes, unlike those made by Metolius, Sterling, and Black Diamond that use six links of the same size. The first three links are 11 inches long, and the last three links are 3.5 inches long. These differing lengths allow you to attach to different anchors at a belay station. Each link is rated with a tensile strength of 24 kN, much higher than that of sewn slings and carabiners. That amount of link strength, however, is overkill since it’s nearly impossible to generate that amount of force in a climbing fall.
The chain’s high breaking strength of 22kN is similar to that of other personal tethers, while the tensile strength of each ring is 24kN. The Metolius PAS 22 and the Black Diamond Link Personal Anchor System are both rated at 22kN, while the lightweight Metolius Alpine PAS is 14kN. When girth-hitched to your harness, it’s stronger than any other gear on your trad rack. The belay chain is constructed with a round-coiled Dyneema core and covered with an abrasion-resistant sheath, which increases the tether’s durability and life if you’re climbing lots of pitches.
The Mammut Belay Chain weighs 3 ounces, slightly less than the 3.3 ounce Metolius PAS 22, and is 120 centimeters in length. This is a good length since it’s easy to clip to most anchors, but not so long that it’s difficult to carry on the side of your harness. I wore the chain girth-hitched to my harness tie-in loop and clipped to a rear gear loop.
The big problem with the Mammut Belay Chain is its bulkiness. The chain, until it is broken in, is stiff and awkward to use. Both Shelton and Waugh complained that the links didn’t lie flat against their harnesses, often tangling on cam lobes and occasionally clipping onto racked quickdraws. Other tethers, like the Metolius PAS and Black Diamond Link Personal Anchor System, are made with flat material so they are less bulky.
It was difficult to figure out the varied anchor clip-in configurations of the Mammut tether without consulting the accompanying directions. The different-sized loops make it easy to equalize two pieces of gear at a belay, but we rarely used it to clip into multiple trad anchors. Instead we used long slings or a cordelette to equalize the anchors, and then clipped one of the chain loops into a locking carabiner on the master point. The chain, made of static Dyneema, doesn’t stretch to absorb a fall, and should not be used in dynamic situations.
Personal tethers were designed for clipping into anchors after climbers became aware of the dangers of using a daisy chain. Daisy chains should be used primarily for aid climbing because they are designed to support static body weight only, and should never be used as an anchor point or for equalizing an anchor. Even a short fall on a daisy chain can pop the pocket and lead to failure. A personal tether is best for clipping into anchor points, either at a belay ledge, while rappelling, or even when hanging on a piece of gear. While using a sling for this purpose works fine, a tether with sewn links allows you to tie snugly into anchors. Plus, if you want to extend a simple 2-foot sling, then you have to add another sling to the system, which usually makes the system too long. When I guide clients on short routes, I usually use a 2-foot sling as their tether. But on multipitch routes and alpine routes, I prefer to use a tether with sewn links.
Pros: Strong; convenient for quick anchoring; durable.
Cons: Doesn’t stretch with poor fall absorption; bulky.