Finding My Sweet Spot

Experimenting with Binding Position and Delta

First Disclaimer… my binding set-up is largely based on feel and feedback rather than hard numbers.

This has taken many hours on snow deciding how I want to ski and what I need my skis to do. And a lot of that is done through experimentation and outside feedback, or otherwise known as F around and Find Out.

Second Disclaimer… my bindings are not set at manufacturer recommended positions. They are set to the proper DIN for me and to the proper forward pressure.

Binding Position Changes How a Ski Feels

Where you place a binding affects how a ski feels and performs. The further forward it is, the easier it is to steer and pivot, but it may feel less stable or carve as well. The further back it is, the more directional and stable it can feel, but the more work it may take to pivot or skid.

I have found a pattern over the past several years in binding position. The more on-piste a ski is classified, the more I like how it skis, meaning the binding is about where I would like it. The more off-piste a ski is classified, the more I have felt too far forward, to the point where, on some, it has felt like the tail is pushing me through the turn.

The Other Variable: Delta Angle

Another consideration of binding set-up is delta angle. Delta angle is the difference between the height of the toe piece of the binding where the boot sole makes contact (usually the AFD plate) and the height of the heel piece where the boot sole makes contact (usually just behind the brakes).

Without shims, these measurements are fixed, so the same toe-to-heel height difference produces a larger delta angle as boot soles get shorter.

Delta angle, like ramp angle in a ski boot, changes the geometry of your position over the ski and can make it easier to put pressure toward the front of the ski. Personally, due to my ankle mobility, leg strength, and technique, I prefer as little ramp in my ski boot and as little delta angle in my bindings as possible.

Ramp and delta angle are interchangeable terms, but for the most part technical discussions use ramp relative to the ski boot and delta angle relative to the binding.

What Am I Trying to Change?

Reducing delta angle changes that relationship by bringing the heel and toe closer to level. For me, that means feeling less pitched toward the front of the ski and having more room to use my ankle rather than starting from a position where it is already partially closed.

The goal isn’t to move my weight backward. It’s to give me a more neutral starting position from which I can move forward and back as needed.

Too little delta could create the opposite problem for another skier, making it harder to access the front of the ski. Like everything else here, the right amount depends on the skier.

Finding the Center of the Running Surface

Prior to ski manufacturers placing recommended boot center locations on skis, there was a methodology to mounting bindings that placed the ball of the foot over the center of the running surface of a ski.

The running surface is different from overall length, and in measuring seven pairs of my skis, I came to an interesting pattern, but more on that later.

How I Measure It

I place the ski on a flat surface that supports its whole length and pull up the brakes. Then I put a little pressure on the ski to remove the camber and run a playing card underneath until it just sticks. I mark those locations on the tip and tail and measure between them.

After finding those two running surface marks, measure between them, halve the distance, and use that location as the approximate target for the ball of your foot.

If I’m setting up a flat ski (no race or system plate), I then like to measure back and mark boot center, as that is what most binding jigs use for referencing.

Seven Skis, One Interesting Pattern

The seven skis I measured were:

• a 165cm World Cup Slalom ski

• a 193cm World Cup Giant Slalom ski

• three All-Mountain skis at 180cm, 185cm, and 191cm

• two Alpine Touring skis at 179cm and 191cm

  
  

The World Cup Slalom and the three All-Mountain skis all had running surfaces between 143cm and 146cm.

So, just 3cm of running-surface difference despite 26cm of overall-length difference.

The two Alpine Touring skis were also within 3cm of each other, with the longer one actually having less running surface due to its highly rockered profile.

The World Cup Giant Slalom ski had the most running surface at 174cm.

Obviously, seven skis isn’t enough to establish a rule, but I found the pattern interesting.

Working With the Binding

My two race skis have mounting plates that limit me to three toe-piece locations, each about 10mm apart. The 180cm All-Mountain ski is on a system binding (the toe and heel slide onto a fixed rail), and the rest are flat, so I can put the bindings anywhere I like.

On the two race skis, the ball of my foot pretty much lands right with the toe piece in the center position. On the system binding, I end up sliding the binding back two positions from the recommended location, which is roughly 8mm.

Establishing My Reference Ski

Still with me…

I have been getting feedback that I am skiing some of my best on the 180cm All-Mountain ski. That is important because it is going to be the reference for all my other set-ups.

My Reference Set-Up

180cm — Overall length

146cm — Running surface

93cm — Tip to Ball of Foot

54% — Overall ski length in front of boot center

~0.5mm negative — Binding delta

Going into this season, I am matching, as closely as I can, those numbers across all my skis.

Why Am I Trying to Match Them?

Not to make every ski feel the same—they’re different skis designed to do different things.

What I’m trying to create is a more consistent relationship between me and the ski. If my position over the ski and the amount of delta under my boot are relatively consistent, then hopefully I don’t have to adapt my stance and movements every time I change skis.

The ski can still behave differently because of its length, shape, construction, and intended purpose, but I’m starting from a more familiar place.

At least that’s the theory.

So, here is what I have had to do to accomplish that.

Applying It Across the Quiver

165cm World Cup Slalom

The World Cup Slalom is 165cm long, has a 143cm running surface, and, with the ball of the foot located at the center of the running surface, will have just under 56% of the ski forward of boot center.

This is actually one binding position forward of where I had the ski last year.

The toe piece is approximately 3.8mm lower than the heel. So, in order to get closer to my favorite All-Mountain ski, I have purchased 4mm of lifter plates to put under the toe.

193cm World Cup Giant Slalom

The World Cup Giant Slalom is 193cm long, has a 174cm running surface, and, similar to the slalom ski, will have 56% of the ski forward of boot center.

I added 2mm of lifter plates to this binding—slightly different binding design than what’s on the slalom ski—to get it to almost exactly 0° delta.

185cm & 191cm All-Mountain

The two other All-Mountain skis are:

185cm — 143.5cm running surface

191cm — 145cm running surface

With the ball of the foot over the center of the running surface, both will have 54% of the ski in front of boot center.

To get there, the binding on the 185cm ski is 20mm behind the recommended location, and the 191cm is 10mm back.

The toe piece of the bindings on those skis is 6.5mm lower, so I will be putting a combination of 3mm and 4mm plates under the toe pieces.

Frequently you can find lifter plates made for specific bindings, but for the All-Mountain skis I'll be making my own plates out of ABS plastic purchased online. I may also need to purchase longer screws so be aware if trying modifications like this yourself.

To be fair, I have loved those skis in soft snow conditions, and I’m mostly making the changes in delta for the sake of the experiment. But, in theory, this should shift my position slightly back on the ski and allow me to stay more neutral or even driving forward - even in deeper snow.

179cm Alpine Touring

On the 179cm Alpine Touring ski, the binding location is right in line with the above skis at 55% of the ski in front of boot center.

The heel of that binding is 1.25mm lower than the toe, but because I only use that ski for touring over performance, I won’t be making any changes to it.

191cm Alpine Touring: The Interesting One

The 191cm Alpine Touring ski is an interesting case, though. I have always felt too far forward on it and wanted to move back to feel comfortable.

Both of these touring skis, because of the tech toe, require me to use a different boot that isn’t as high-performance as my everyday boot, and I’m still working on perfecting it.

But the binding on the 191 has 4.75mm of delta, and the boot center location is at 52%.

For that binding I will be adding 5mm of lift under the toe and also moving the binding back another 4cm.

It’s either going to improve that ski or I’m going to have an inexpensive touring ski for sale in the near future.

So, What Am I Taking From This?

You don’t have to take manufacturer binding location as a given and, other than system bindings, delta can also be changed on bindings designed to accommodate it.

A center-mounted ski will have 50% of the ski in front of and behind boot center. In my measurements, a race-plate ski could move as far back as 56%.

None of this means these are universally correct numbers. I’m using the ski I like most as a reference and seeing whether I can reproduce some of its characteristics on my other skis.

To find your ideal location, you need to evaluate how you want a ski to feel. If it’s carving you like, then having a higher percentage of the ski in front of boot center could work. If you like a bit more skid and steer in your skiing, then having a lower number (but probably not past center mounted) could work for you.

Delta angle will also affect how you feel, whether it be more on the toe or on the heel, and changes there should factor in your biomechanics and strength.

If you have a ski you really love, take its measurements and see what you might need to do to match it.

Obviously, any changes to binding geometry need to be compatible with the binding and should be checked by a qualified technician.

Happy Experimenting!

If you enjoyed this article please subscribe to receive automatic updates of future articles and feel free to leave a comment, too.