Ski binding

Alpine touring ski boot, binding, and ski crampon

A ski binding is a device that connects a ski boot to the ski. Generally, it holds the boot firmly to allow the skier to maneuver the ski. However, if certain force limits are exceeded, it releases the boot to minimize skier injury, such as in the case of a fall or impact. There are different types of bindings for different types of skiing.

Alpine

Example of ski binding mounted on a plate

Snow brake in open position

Modern alpine skiing bindings fix the boot at the toe and heel.

In some bindings, to reduce injury the boot can release in case of a fall. The boot is released by the binding if a certain amount of torque is applied, usually created by the weight of a falling skier. The torque required is adjustable, according to the weight, foot size, and skiing style.^[1] A snow brake prevents the ski from moving while it is not attached to a boot.

Also known as randonee, an alpine touring binding allows the heel to be clipped down to the ski when skiing downhill, but allows it to be released when climbing.^[2]

Nordic

Cable binding

The cable binding was widely used through the middle of the 20th century. It has the toe section of the boot anchored, and an adjustable cable around the heel secures the boot. While binding designs vary, before 2007 almost all dedicated Telemark models had been designed to fit boots with 75mm Nordic Norm "duckbill" toes.

Rottefella (NN, Nordic Norm)

Rottefella 75 mm Nordic Norm (NN)

The Rottefella binding was developed in 1927 by Bror With. The name means "rat trap" in Norwegian. It is also known as the 75 mm, Nordic Norm, or 3-pin. After victories at the 1928 Winter Olympics in St. Moritz, the binding remained the standard for cross-country skiing for the next 60 years. They are no longer as popular as they were but are still for sale. The binding has three small pins that stick up from the ski. The toe of the boot has three holes that line up with the pins. The boot is then clamped down by a bail. The binding is asymmetrical, having left and right foot orientations.

NNN (New Nordic Norm) & NIS (Nordic Integrated System)

NNN binding: similar to SNS Profil but using two ridges

Rottefella's NNN (New Nordic Norm) has a bar in the toe of the boot hooked into a catch in the binding. There have been several versions of NNN, and the first NNN version is not compatible with current designs. It also exists in the more rugged BC (Back Country) version.

NIS (Nordic Integrated System), introduced in 2005 by Rossignol, Madshus, Rottefella, and Alpina^[3] is fully compatible with NNN boots and bindings, but is a different way of attaching the bindings to the ski.^[4] It features an integrated binding plate on the top of the ski to which the bindings attach, allowing adjustment in the field. NIS skis allow installation of non-NIS bindings. In 2007, Fischer abandoned SNS and entirely switched to NIS.

SNS (Salomon Nordic System)

SNS Profil binding: one large ridge and one metal bar on the boot

SNS Pilot binding: same ridge as SNS Profil, but two bars on the boot for better stabilization

SNS (Salomon Nordic System) looks very similar to NNN, except it has one large ridge and the bar is narrower. Three variants exist:

• Profil: the standard model (with one metal bar in the toe of the boot)
• Pilot: for either skate-style or classic-style cross-country skiing (with two metal bars on the boot)
• X-Adventure: for backcountry skiing.

Pilot skate boots can be used with a Profil binding but Profil boots cannot be used with Pilot bindings. SNS is marketed by Salomon and Atomic (both of which brands belong to Amer Sports group).

NTN (New Telemark Norm)

In 2007 Rottefella introduced the New Telemark Norm binding. The system's objective is to provide a freeheel telemark ski binding featuring lateral release, increased lateral rigidity, tunable performance, and free-pivot touring functionality.^[5]

History

Old ski binding

In the early days of skiing the binding was also similar to those of a contemporary snowshoe, generally consisting of a leather strap fastened over the toe of the boot. In the 1800s, skiing evolved into a sport and great advances in technique and equipment design followed. The toe strap was replaced by a metal clip under the toe. This provided much greater grip on the boot, allowing the ski to be pushed sideways. The heel strap also changed over time; in order to allow a greater range of motion, a spring was added to allow the strap to lengthen when the boot was rotated up off the ski. This buckled strap was later replaced by a metal cable.^[6]

Sondre Norheim demonstrated Telemark skiing before 1866, and the Open Christiania in 1868, both made possible with a binding design (which dated back to the late 1840s). This binding innovation, also credited to Sondre, added a loop of twisted birch roots that ran from the existing birch root toe loops around the boot heels and back. This stiff heel loop allowed the heel to lift as before, for walking and gliding, but better held the boots to, and aligned with, the skis allowing greater torque to pivot the skis in a new direction than when the boot could easily pivot sideways in the toe loop. This enabled Sondre to control the skis with his feet and legs, replacing the former technique of dragging a large pole in the snow on one side or the other to drag the skier in that direction.^[7] These new techniques spread throughout Telemark and would later be named for the region.^[8] In 1894: Fritz Huitfeldt invented a binding with a secure toe iron which allowed the heel to move freely. This became the standard industry binding through the 1930s.

The release binding, the Saf-Ski, was invented by Hjalmar Hvam in 1939.

In 1955 the then world's leading ski boot company, Henke, introduced boots with buckles. It was not widely-adopted until the early 1960s, when Lange used them on their new plastic ski boots.^[9] Salomon introduced the rear-entry boot in 1984.

In the earlier days of skiing, the skis were in a design somewhat similar to snowshoes, roughly a walking motion, although they were slid over the snow instead of lifted with each stride. During this era, the binding was also similar to those of a contemporary snowshoe, generally consisting of a leather strap fastened over the toe of the boot.

During the 1800s, skiing evolved into a sport and great advances in technique and equipment design followed. Generally the skiing motion was much closer to skating, using long gliding strides. This technique required bindings that followed the skier's foot through a wider range of motion, but loosening the toe strap simply made it fall off. To address this, a second strap was added that looped from the toe around the heel of the boot, pulling it forward into the toe strap.

Over time, both portions of the binding evolved. Early on, the toe strap was replaced by a metal clip under the toe that folded up on the sides to cup the toe of the boot. This provided much greater grip on the boot, allowing the ski to be pushed sideways. The heel strap also changed over time; in order to allow a greater range of motion, a spring was added to allow the strap to lengthen when the boot was rotated up off the ski. This buckled strap was later replaced by a metal cable, or in some cases a single large metal spring. By this point the bindings were generally known as cable bindings.

The introduction of the cable binding allowed the Christie turn to become a standard on downhill runs, and to further support this style of skiing the Swiss racer Guido Reuge in 1929 invented a cable binding with steel clips below the boot heel to enable clamping the heel down for downhill portions. He named the product "Kandahar" for the international Kandahar Cup ski races.^[10] In use in alpine races, the Kandahar binding led to serious leg injuries, and by 1939 experimentation began in earnest on bindings that would release the boot in a fall.^[11]

The evolution of bindings for alpine skiing wasn't complete until the introduction of plastic ski boots (beginning in 1966) permitted the development of industrial standards for binding function. Injury rates began to fall with the gradual introduction of the Teflon anti-friction pad around 1972.

Cable bindings remained in use for some time for cross-country, and are today popular for telemark skiing. However, the Rottefella design from the 1930s became more popular for cross country skiing through the 1950s and into the 1970s, and the Salomon Nordic System (SNS) binding re-invented this field entirely. Today cross-country binding systems have become as customized as their downhill counterparts of the 1960s.

Modern ski bindings are based on the Fennoscandian model of the 19th century. The bindings of Telemark ski and cross-country skis were developed from the Ugro-Lapp type.

Norheim's binding

One of the first recorded advances in binding design was made by Sondre Norheim, the "father" of modern skiing. His binding included a leather toe strap that was fastened tightly with a buckle, and a heel strap of small birch roots twisted into a rope. The heel strap started at the toe, looped around the heel, and forward again to the toe. The heel strap pulled the boot forward into the toe strap, so the ski would not fall off when pressure was released on the toe. The strap had to be flexible and elastic in order to allow it to keep tension on the heel as the skier strode forward and the heel lifted from the ski.^[12]

First introduced in 1850, Norheim's binding allowed a much longer striding motion that greatly increased cross-country speeds, and this quickly became widespread. It also allowed the ski to be directed by twisting the foot, transmitting the torsion to the ski through the toe strap. Techniques based on this ability were developed over the next few years, replacing the former technique of dragging a large pole in the snow on one side or the other to drag the skier in that direction. These new techniques spread throughout Telemark and would later be named for the region.^[13] Norheim made a splash when he introduced this publicly at an 1868 ski jump meet, where the contestants were required to ski up the hill, down the hill to the top of the jump, and then jump, with their style being marked on all phases. Norheim's smooth linked turns stunned the crowds, and he won the competition.

Huitfeldt's advances

A late model Huitfeldt-style binding. The toe clip runs through the core of the ski to bend up on either side. This model uses a metal heel strap with a lever buckle instead of an all-leather design.

Fritz R. Huitfeldt drove the evolution of the ski binding over the next 20 years. In 1894 he introduced the use of semi-circular metal hooks at the toe to attach the straps. The hooks were positioned to tightly fit to the sides of the boot, keeping the ski centred and eliminating any "flop" that the formerly loose straps allowed. The heel strap was also attached to the same hooks, but because of their rounded shape, the required range of motion was provided by the straps sliding up and down on the hooks. This allowed the heel strap to be replaced by a less flexible leather strap. Together, these changes dramatically tightened the binding, greatly increasing control.^[12]

In 1897, Huitfeldt further improved the design by changing the toe piece. Instead of hooks, he drilled a rectangular hole through the ski from side to side, and passed an iron bar through it. The bar was then bent up on either side, locking it in place, and then formed to fit the toe of the boot. This improvement once again dramatically improved the firmness of the fit. Finally, in 1904 he adopted the Hoyer-Ellefsen toggle, a lever that replaced the buckles.^[14] This not only greatly improved mechanical advantage, further improving the strength of the binding, but also made the system much easier to put on and remove. Better yet, the geometry of the attachment points meant the heel strap was mechanically attached below that of the toe strap, which provided a constant "diagonal downpull" that naturally returned the heel to the ski.

Huitfeldt style bindings were by far the most popular system for decades, with the only major change being Marius Eriksen's 1920 introduction of pre-formed plates that were screwed on top of the ski.^[14] Other binding systems did exist, in particular a class of bindings originally introduced by Mathias Zdarsky that replaced the heel strap with a long metal plate under the sole of the boot, hinged at the front to allow the heel to rise. The heel was held to the plate by a short strap attaching at the back.^[15] These gave even better control than the Huitfeldt design, but so firmly attached the leg that injury was a real problem.

Cable bindings

A major advance on the Huitfeldt concept was introduced to the market by Guido Reuge in 1932. Reuge replaced the heel strap with a metal cable connected to a spring at the front of the toe. The spring provided even tension as the boot moved. Previously, the strap was adjusted so it had enough slack to allow the boot to rotate as high as the skier wished, but as the boot rotated back down to the ski it became increasingly slack again. The cable removed this limitation, and held the boot firmly through its entire motion, greatly increasing the solidity of the fit. A later advance added two small metal clips near the rear of the foot that the cable could be clipped under. These held the boot firmly to the ski during downhill portions of the runs.

Safety bindings

In 1937 Hjalmar Hvam broke his leg skiing, and while recuperating from surgery, invented the Saf-Ski toe binding. This was a metal clip with a pyramidal top that fit into a slot cut into the sole of the ski boot. When the boot was rotated forward, the slot on the toe eventually rose above the metal pyramid, allowing the toe to release from the ski. The system was considered with suspicion by professional skiers, especially when Olaf Rodegaard released during a race. However, Rodegaard credits the release with saving him from a broken leg.^[16] In the post-war era, Hvam sold several thousand pairs of Saf-Ski's, in an era when downhill skiing was in its infancy. Hvam continued to sell the Saf-Ski into the 1960s, but in 1966 his insurance rates increased so dramatically that he was forced from the market.^[17]

A dramatic advance was introduced as the Look Nevada in 1950. The Nevada held the toe centred over the ski using two metal fingers shaped into an upside-down V. The fingers were pivoted to allow motion to the sides, and centred with a spring. During a fall, sideways torsion could overcome the force of the spring and allow the boot to release directly to the side. This design was quickly copied by other vendors, notably Marker, and had the first real impact on the dominance of the classic fixed-toe bindings. By the late 1950s, there were about 35 different release toe bindings on the US market,^[18] most of which used a normal Kandahar-style heel cable.

The first modern heel-and-toe binding was the Cubco binding, first introduced in 1950 but not popular until about 1960. A heel-release binding faced the problem that there was no obvious place to attach to on the heel, so the Cubco solved this by screwing small metal clips into the sole of the boot. This also eliminated the changes in performance as the sole of the boot wore down, or the geometry of the sole changed as the boot wore into the skiers foot.^[18] Marker introduced the Rotomat, which gripped onto the sole where it extended past the heel, and Look quickly followed suit with their Grand Prix design. By the mid-1960s, release bindings that worked on both the heel and the toe were common, and by the late 1960s the cable binding had disappeared from downhill.

Salomon 347 bindings, typical of a 1980s beginner design. This binding features a Nevada-style pivoting toe, a step-in-step-out heel, and an integrated ski brake. Designs have changed little since this era.

One problem with 1960s release bindings was that the boots were not standardized, and a binding that worked well on one boot might be dangerous on another, or might become dangerous over time as the boot shifted about. This led to the introduction of plate bindings, which used a metal plate firmly clipped to the sole of the boot, and bindings that clamped onto the plate. The plate could be easily removed for walking about. Plate bindings were popular in the US in the 1970s, notably the BURT Retractable Bindings and Spademan binding, but never caught on in any major way in Europe. As more and more of the downhill ski market came under control of European companies, the plate bindings disappeared, in spite of their excellent safety records.^[19]

The disappearance of the plate and alternate systems was due to a combination of factors, notably the introduction of standardized hard plastic boots. Plastic was first introduced by Lange as a way of improving existing leather designs. As the new material spread through the industry, the sole piece was standardized to allow toe-and-heel bindings to clip on. Plastic had the advantages of being much firmer than leather, not changing shape over time, and having predictable friction characteristics wet or dry. Although plate bindings of the era had much better safety records, notably the Spademan design, the new boots and bindings could be easily adapted to any ski for any skier.

Cross-country

The cable binding remained in use, and even increased in popularity, throughout this period as cross-country skiing developed into a major sport of its own. In this field the speeds were generally not high enough that the release was a serious concern, and the freedom of the free-heel design was perfect for the sport.

A typical Rottefella cross-country binding. The ski boot has small holes that fit over the pins seen on the bottom of the plate, keeping the boot from sliding rearward. The metal bar clamps the toe down onto the pins, and can be released by pressing down on the plastic clip with a ski pole.

Change eventually came though the evolution of the Rottefella binding, first introduced in 1927. The original Rottefella eliminated the heel strap, which held the boot forward in the binding, by drilling small holes in the sole of the boot which fit into pins in the toe piece. This would only work if the sole was held very firmly down on the pins, so the binding also introduced a metal clip that was forced down onto the top of the sole of the boot, forcing it onto the pins. When the inventor, Bror With, won a race on the new design, Norwegian Crown Prince Olav ask him what they were, and he responded "Oh, they're just a couple of rat traps I picked up at the hardware store".^[20] "Rottefella" is Norwegian for "rat trap".

Problems with the geometry of the boot sole, which meant only certain boots would work, meant the Rottafella was not widely used. This problem was eventually solved through the same evolution of plastic components that changed the downhill market. In this case the use of highly flexible plastics allowed for a sole that was very strong torsionally and side-to-side, but still had excellent flexibility lengthwise, allowing the heel to rise as with a cable binding. This was standardized as the 3-pin system, which was widespread by the 1970s.^[20]

A similar system with a 50 mm "duckbill" once existed for lighter setups, but is obsolete and no longer available. Unlike the 75 mm it was symmetric. It was the binding of choice for racing, prior to the adoption of skate ski racing, in the early 1970s. The 50 mm was also designated according to the thickness of the "duckbill" having either 7 mm or 11–13 mm thick soles hence these bindings often had two notches in the bail to clamp boots with different sole thicknesses.

References