What you need to know about alpine bindings

[volklgirl]

Alpine Bindings – What You Need to Know

While bindings are probably one of the least glamorous pieces of equipment you’ll buy, they’re also one of the most important. In general, they won’t directly affect the amount of fun you’ll have on the slopes, but their failure could easily ruin your day. Fortunately, all the major binding manufacturers make safe, effective bindings so, while binding choice for some is very personal, it’s also fairly easy for the average skier. Keep in mind that no binding will function adequately when mated with a badly fitted boot. If the skier’s boot is big enough to allow any upward or twisting forces within, the bindings will never get the message to release. So get those boots properly fitted!!!

ANATOMY OF A BINDING
The main parts of a binding are: the toe piece, the heel piece and mounting plate, the antifriction device (AFD), the brake assembly, and possibly a lifter or connector plate.

The Toe Piece
The toe piece is designed to hold the toe lug of the boot securely during skiing, while at the same time releasing in a reliable manner when subjected to sideways and twisting forces of a predetermined magnitude. Some manufacturers have been trying to add release characteristics during upward forces as well with varied and somewhat limited degrees of success. Currently, there is no widely available binding that will protect the skiers’ knees and ACLs reliably during backward twisting falls despite much effort to design one. In most cases, the toe piece is mounted directly to the ski; although the current trend is to mount a plate to the ski then mount the toe piece to that.


Every toe piece will have:

1. A set of wings that grip the boot toe lug. Some manufacturers employ mechanically movable wings while others allow the entire head of the toe piece to pivot for release.
2. A DIN adjustment screw and value indicator window that allows the binding tech to set the range of pressures required to get the toe piece to release the boot lug.
3. An AFD, which reduces the friction created as the boot sole, slides across the toe piece and allows the toe lug to release smoothly and consistently. In most models, the AFD is a small white rectangle of Teflon. Marker uses a sliding metal plate and Tyrolia uses a rolling rubber strip in some of their models.

Some toe pieces may also have:

1. A screw for toe height adjustment to account for variations in boot toe lug heights and to accommodate the generally thinner lugs on junior and child boots.
2. A release mechanism to allow the entire binding and plate to move forward or backward within the mounting tracks to change the turning characteristics of the ski or to adjust for differences in skiers’ center of mass.

The Heel Piece
The heel piece is designed to hold the heel lug of the boot securely during skiing, while at the same time releasing in a reliable manner when subjected to upwards and twisting forces of a predetermined magnitude. In addition, the heel piece allows the skier to manually release the boot from the binding by means of pressing on a release lever. The heel piece is always mounted to the skis using some type of plate. This allows the heel piece to move forward and backward within the plate to adjust the size of the binding for variances in boot sole length.

Every heel piece will have:

1. Some form of release lever. Some manufacturers design in a “soft step-in” feature to enable the skier to step into the binding with less force while in deeper snow.
2. A “heel cup” that secures the boot heel lug.
3. A brake assembly that is designed to retract out of the way when the boot is locked into the binding but will deploy to prevent a runaway ski in the event of a binding release. Almost all current binding designs come with wider brakes or have an optional wider brake assembly available to accommodate today’s fatter skis.
4. A DIN adjustment screw and value indicator window that allows the binding tech to set the range of pressures required to get the heel piece to release the boot lug.
5. Some method to adjust size for different boot sole lengths and to set the appropriate forward pressure. Forward pressure determines how much flex the binding will tolerate before releasing the boot sole. Appropriate forward pressure allows the ski and binding to flex fully while still retaining the boot securely. Too much forward pressure will lock the binding to the boot so it won’t release while too little will allow the boot to pop out any time the ski encounters the slightest variation in terrain.

The Mounting/Connector/Lifting Plate
There are several types of plates having different functions:

• Mounting Plate – the mounting plate has a set of tracks that allows the toe and heel pieces to be moved independently within those tracks giving the binding adjustability for a very large range of boot sole lengths or to be moved together to move the skier’s center of mass forward or backward along the length of the ski. Mounting plates are typically used on rental skis.
• Connector Plate – the connector plate is designed so that the only toe piece and the mounting plate for the heel piece are mounted directly to the ski. The heel piece is then connected to the toe piece by the connector plate and merely “floats” along the mounting plate allowing the ski to flex freely below the connector plate, eliminating the flat spot in the ski flex created by the boot sole. Many manufacturers also add some form of vibration damping or control enhancement devices to the design of the plate. Some manufacturers also add the ability to move the entire plate and binding forward or backward along the ski. Connector plates are used on both flat and system skis.
  
  
• Lifter or “Race” Plate – the lifter or race plate raises the binding and boot sole up above the top skin of the ski giving the skier additional leverage over the ski to allow greater edge angles while helping to prevent the widest point of the boot shell from hitting the snow causing the ski to bounce out of the turn, known as “boot out”. It also tends to stiffen the ski for more power. Some manufacturers also add vibration damping or control enhancement devices to the design of the plate. Race plates are used only on flat skis.

 

[volklgirl]

Alpine bindings Part 2

SYSTEM SKIS AND BINDINGS
Many manufacturers have been designing skis with the binding mounting system as an integral part of the ski construction, usually using some form of rails or tracks. These skis are called “system” skis and are typically aimed at high speed cruising on groomed terrain. There are several reasons for this approach:

• It can make the binding mounting area strong and more resilient because the bindings are mounted into the ski’s structure rather then just screwed through the top skin and into the core of the ski.
• It allows the binding to be mounted directly to the ski at only one or two points, enabling the ski to flex fully beneath the binding and boot sole (one of the biggest reasons for the initial success of the super-shape skis we are using today).
• It allows a huge range of adjustments for boot sole length and the ability to move the binding along the track to account for different skiers’ center of mass.
• It typically lifts the binding above the surface of the ski allowing for greater leverage and increased edging on groomed or icy terrain.
• It isolates ski vibration from the binding interface making for a smoother ride.
• It simplifies binding choice for the purchaser.

There are issues with this approach, however:

• The lifted binding can be an issue on fatter skis in softer snow where the increased leverage is not an advantage, or on park skis where the lift creates a less stable platform for stomping landings.
• It limits the available binding choices for more experienced skiers.
• It limits or eliminates the ability to cant the ski to account for differences in skiers’ anatomy.
• Systems tend to be much heavier than the comparable flat ski and binding combination.

Systems skis:

Close-up of a “System” ski

The full flex allowed by a system ski/binding combination

OTHER FEATURES AND CONSIDERATIONS
DIN
DIN is the abbreviated name of the Deutsches Institut für Normung (German Institute for Standardization). In the case of ski bindings, the DIN standardization ensures that all bindings release at the same rate for any given force. Binding DIN is determined based on the skier’s weight, height, ability level, length of the boot sole, and in some cases, age. Every skier should know their own DIN setting! As bindings age and undergo repeated retention and release cycles, the characterisitcs of the springs used in the bindings undergo changes in spring rate. To ensure that the binding continues to release at consistent torque rates, most binding manufacturers highly recommend yearly testing by certified technicians. Here are 2 of the current charts that are used by ski technicians to set and test the release torque values and the directions for their use:

Determine the type of skier, from one of the following groups:

• Type 1 - Cautious skiing at lighter release/retention settings. Skiers who designate themselves "1" must accept a narrower margin of retention in order to gain a wider margin of release.
• Type 2 - Average/moderate skiing at average release/retention settings. Skiers who designate themselves "2" must accept a balanced compromise between release and retention.
• Type 3 - Aggressive, higher speed skiing at higher release/retention settings. Skiers who designate themselves "3" must accept a narrower margin of release in order to gain a wider margin of retention.
• Type 3+ - For skiers who desire visual indicator settings higher than settings for a Type 3 skier.
• Type -1 (neg. 1) - For skiers who desire visual indicator settings lower than settings for a Type 1 skier. For skiers 38 lbs. and under, Skier Type -1 is inappropriate.

Step 1
Find the release Code (letter A through P) that corresponds to the skier's weight, as well as the Release Code that corresponds to the skier's height. If they are not the same, choose the one that is closer to the top of the chart. For example if the skier's weight is 175 lbs. (code L) and the height is 5'7" (code K), choose code K as the correct line of the chart to be reading.
Step 2
Make the adjustments for skier type and age.
The selection from Step 1 is for a type "1" skier. If the skier is a type "2" move down the chart one code. If the skier is a type "3" move down the chart two codes. If the skier is age 9 or under, or age 50 or over, move up the chart one code. Note and record the final Release Code letter for the skier.
Step 3
Reading on the corrected release code line from Step 2, find the column with the skier's boot sole length. Within the box that corresponds to the skier’s Release Code and his or her boot length is a number. This is to be used as the DIN setting for the toe and heel bindings.

For anyone who just went “huhn???” after all those directions, here is an on-line calculator: https://www.dinsetting.com/

 

[volklgirl]

Alpine bindings Part 3

OTHER FEATURES AND CONSIDERATIONS
Vibration Damping
Binding manufacturers employ many methods to isolate the vibrations of the ski from the sole of the boot. Some put rubber pads in various places in the binding, some employ lifter plates, and others add actual rubber modules or mechanical devices to their connector plates. One example of this is Marker’s Piston plate where the back of the plate and the front of the plate are pushed together, putting a small oil-filled shock under pressure. Then, as the ski bends and vibrates, the shock pushes outward, keeping the vibrations to a minimum and isolating those vibrations from the skier’s boot.

Elasticity
When discussing bindings, elasticity refers to the amount of ski and binding flex a binding will tolerate before reaching the point where the heel piece will release. Some manufacturers are known for producing more elastic bindings, particularly Look and Rossignol. Others, like Marker, are known for being less elastic.

Indemnification
As the materials used in bindings age they break down, both from usage and from time and exposure to the elements. At some point, depending on the materials used in the binding, the binding is no longer considered safe for use (indemnified). Each year binding manufacturers publish a list of bindings they still consider safe for consumer use, usually in their yearly tech manual. Each year the NSSRA (National Ski and Snowboard Retailers Association) and the SIA (SnowSports Industries America) publish a compiled list that includes all the major manufacturers. Almost all shops will refuse to repair, mount, or adjust any binding not on the indemnification list due to liability issues.

Delta Angle
Almost all bindings are created with the heel piece having more rise than the toe piece. This creates a lift angle between the 2 pieces. The measurement of that lift angle is called the Delta angle. This angle should be taken into consideration along with the ramp angle and forward lean of the skier’s boots and the mounting point of the binding to create a strong and balanced position for the skier.

Mounting Point
Most skis are made with a “mounting point” picked by the manufacturer and printed on the side or top skin of the ski. In most cases, this is an acceptable starting point for choosing where to mount the binding and is based on an “average” skier with an “average” boot size. Especially for skiers with smaller boot sizes and for most women whose center of mass are lower and farther back than the “average” male skier, this is not always the optimum place to mount the binding. Many women, instead, prefer a mounting point between 1 and 3 cm farther forward than the mounting mark to help eliminate the feeling of always being “in the back seat”. The best ways to determine the optimal mounting point for a particular skier are to use a Campbell Balancer or to use a movable binding with some trial and error. Determining “the best” mounting point for any skier must also take into account the ramp angle and forward lean of the skier’s boot.

Another consideration when mounting bindings is the ski’s intended use. Skis designed to excel at short turns are typically mounted somewhat farther forward to help drive the tips into the turn while skis used for powder tend to be mounted farther back to enhance the skis’ ability to float. Twin Tips are often mounted right in the center to make them equally at home while going forward or backward and to enhance their balance while sliding on rails.

Binding Width
With the advent of fatter skis came concerns regarding how to get edging motions from the skier through the bindings to the edges of the skis where the power should be greatest to aid edge hold. With standard bindings, the pressure is concentrated nearest the centerline of the ski. For skis with waist widths of 80+ cm, this centered concentration of pressure allows the outer edges of the ski to flex and twist robbing the edges of bite and power. To address these concerns, some manufacturers have begun making “wide bindings” employing a binding frame that spans the width of the ski and allows the power to be transmitted closer to the edges.

OK, SO HOW DOES ALL THIS AFFECT ME????
For any level of skier, the selection of mounting point and the combination of delta and ramp angle along with forward lean are more important considerations than the type of binding as long as the DIN range of the binding is appropriate. Beyond that, here are some guidelines.

Beginners and lower level intermediates:
Beginners and lower level intermediates do not generate the kinds of speeds and forces that require special considerations in their choice of binding. An appropriate binding is one that is easy to use, has brakes that are wide enough to straddle the ski, and has a DIN range that is appropriate for the skier’s current needs while having enough adjustability to give the skier room to grow.

Upper level skiers:
When choosing a binding, first determine what the primary use of your ski will be. If racing or high speed skiing on hard snow is high on your fun list, or you tend to ride very lively skis, consider a binding with a lifter plate and/or some mode of vibration damping to help smooth the ride and keep the ski’s edges glued to the snow. If deep, soft snow or the terrain park and half pipe is more to your liking, look for a binding without a plate, with plenty of elasticity, and possibly with a “soft step-in” feature. If you plan to use fatties for your all mountain skis, features like switchable vibration damping, fore and aft adjustability, and a wide frame may make your fatties more tractable on the groomed stuff. If you plan to use your fatties for the occasional jaunt in the backcountry, one of the new alpine bindings that also function as a touring binding may be a good choice.