Some of the descriptions in this article are linguistically abstract and may be difficult to understand without holding something analog in your hand. I am trying to make the whole thing more or less tangible for low-tech newbies, even if some things are taken for granted by experienced colleagues. Recommendation: A cozy evening at home, where you can take a look at some of the points in this article yourself on a "living object".
How a ski binding works exactly can be found many times on the internet. Just the basics: A release scenario is always (regardless of whether pin, frame or alpine part) a TOGETHER PLAY between the front and rear jaws and usually an interplay of both release paths: lateral ("sideways") and vertical ("forwards"). With most alpine bindings, the lateral release is set on the toe piece, the vertical release on the rear toe piece. The setting of the release value depends not only on weight, size and skiing behavior (harmonious or aggressive), but also on sole length (lever) and other factors. There is also contact pressure and height adjustment. On closer inspection, things are a little more complex than you might think at first glance - similar to women (Editor's note: and men!!!) or processes in economics.
ISO standard for touring bindings
The standard for touring bindings is called ISO 13992, which is very similar to the alpine standard in many cases. For a touring binding to comply with the standard, the identical release value for different bindings must be within 10% of the defined value. This means, for example, that a set value of 10 is actually somewhere between 9 and 11. - In several scenarios (ski flexed, axial forward pressure of the boot, sticky snow, ...), the release force may usually deviate from the set value by a maximum of 30%. - must have a certain degree of energy absorption (elasticity) because there are often short peaks of force application that do not yet require release.
Most tech bindings fail the TÜV certification (which, of course, is based on ISO 13992) due to the strongly changing release force with flexed (bent) skis, because they have no contact pressure compensation and the hardly existing elasticity of the front jaw (there is only "release" or "engaged" and hardly any play between the two cases). With flexed skis, it pushes the rear pins deeper into the inserts of the boot and the force required for a release is many times higher. The standard also covers several field tests and the functioning of the bindings after a salt water bath, but NOT the release in ascent mode or the interaction of several hindering factors.
How does the release work?
In the end, only one thing counts: foot and ski should separate in time in an emergency. Personally, I don't care whether the binding has a TÜV sticker or complies with a standard, as long as it opens before ligaments, tendons or bones say goodbye. Here is a paper on the subject. The answer from these tests: Tech bindings sometimes release later, sometimes earlier and in the very worst case, the shin can break beforehand. An alpine binding does not always release in time either, but it is usually one step ahead. With a pin binding, both release values must be set on the rear jaw (except Diamir Vipec and Trab TR2). The lateral release is determined by the force required to turn the toe piece and by the spring force of the bar on the toe piece, the vertical release by the force required to push the two pins on the toe piece apart so that they protrude downwards from the insert.
You can take a better look at the later release on a video. Note the movement of the lever on the front part:
Detail of the toe piece:
Back cheek detail:
"Classic" binding models
Work according to the classic system: Plum Guide, Plum Yak, ATK Raider, ATK Free-Raider, ATK RT, all "old" TLT models from Dynafit (today "Speed Turn"), all Comfort and Vertical models, as well as the first Radical ("TLT Radical") and the Speed Radical, as well as corresponding models built by Dynafit but offered by other brands (e.g. "engineered by Dynafit" Radical bindings under the label "engineered by Dynafit").e.g. "engineered by Dynafit" Radical bindings under the label of Fischer, Look, Movement - to name the best known). The Dynafit Superlite 2.0, available since this year, no longer defines its vertical release for weight optimization by two separate pins on the rear jaw, which are pressed apart in the middle by spring force (lying in the housing) and thus pressed against each other at the front end (where the boot snaps in).There are various newer pin bindings which achieve a better release behavior by means of rotating front jaws, contact pressure regulation on the rear jaw and other methods. These bindings (G3 Ion, Dynafit Radical 2.0, the Beast range, Diamir Vipec, Trab TR2), as well as special ski touring race bindings, are dealt with separately in other articles.
