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Ski Stiffness - Hero, Whiteout and #1SC Compared

AlexisLD

Getting off the lift
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Jan 30, 2021
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366
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Quebec
I am down to discuss this more. However, maybe we could try to do it over zoom, Team, skype, etc. I think we exhausted the amount of words we could legally use on forums! :)

What must be recognized is that SoothSki is a business and, as such, there must be a business justification for any moves they make

I have two hats, one from Sooth and one as a university professor doing research on skiing. Even in the university framework, I would need some kind of justification to start a project. But in both cases, we are curious to discover more.

What is challenging with "vibrations" is that no one knows exactly what we are talking about (it is the same in hockey, in golf, tennis, etc). I am not really denying what you are all talking about. I am saying that I would not know what to measure (and even less how to measure it). It can be a very huge time/money sink to search for something when you don't know what it is, specially when a bunch of people already tried. We spent last year doing a ton of measurement on-snow and that didn't bring us very far. Snow varies, the testers are not very consistent, etc. We now have a testbed to measure vibration on ice skating rink (see #2 below). It is promising in that it is much more consistent (e.g., measuring edge grip). Even with this such a testbed, we are still struggling to really define what a good vibration response is.

One of my argument was also that I doubt that anyone out there has actually skied identical skis that just differ in their damping (or any another unknown property). When you do your perception test, are you really sure that one ski didn't had a slightly different torsional stiffness? A different mass? A different shape? Different properties will lead to different vibration generation, which I personally think that is, at this point, more important than damping. But I could be wrong.

We could try to resolve some of these issues with simple perception experiments. Happy to discuss that more if you want. Cool projects have always started with weird idea! ;-)

One thing that could help us to move fast on this is if you could find 5-10 skis from 2021-22 in the Sooth database that you feel are great and 5-10 skis that you feel are terrible. They would need to be relatively similar models (e.g., directional all mountain skis). We could then quickly see if there are some correlations between the properties that we are currently measuring and your ratings... We would not address damping, but we might find something much simpler!

You can look at these:
1. Comparative Study of Ski Damping Technologies by Accelerance Maps (https://www.mdpi.com/2504-3900/49/1/49)... that is super easy to do, but it is hard to figure out which part of the accelerance map is important for on-snow feels.
2. Effect of edged snow contact on the vibration of alpine skis (https://rdcu.be/cAYY7). The latest and greatest, but definitely not the end of that...
 

Vitamin I

one-track mind
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NorCal
For this topic, I contend that the people using words like "vibration", "vibration response", and "damping" are on the wrong track. I can't read the minds of @Noodler and @Dakine, but I suspect there are other words that would more precisely and more accurately describe what they are feeling and what is actually happening.

Different properties will lead to different vibration generation, which I personally think that is, at this point, more important than damping. But I could be wrong.
I agree that impacts sensed by the foot depend on more than just the way energy transmits through the ski. Just one example would be how thoroughly and how "non-abruptly" the front part of a particular ski model "grooms" or flattens a surface inconsistency before the boot zone slides forward and runs over it. Etc.

One thing that could help us to move fast on this is if you could find 5-10 skis from 2021-22 in the Sooth database that you feel are great and 5-10 skis that you feel are terrible. They would need to be relatively similar models (e.g., directional all mountain skis). We could then quickly see if there are some correlations between the properties that we are currently measuring and your ratings... We would not address damping, but we might find something much simpler!
I am willing to do that "work", but not fruitful for me to be the one who does that. I ride long skis, and there's not enough long skis in the SoothSki database yet---only 61 skis in there are >=190cm, and I haven't ridden many of those.

However, if you want, we could analyze 32 of my ski models to find correlations for the properties that I can measure without the SoothSki Tool (no stiffness measurements). I have already A/B Tested 32 of my "old" ski models on-snow, and sorted them by a metric which seems to be same as THIS metric we're talking about here...but first we'd need more precise communication to verify that we're all talking about the same thing here. Pretty sure some "smoother-than-expected" anomalies in my tests are my "lightweight" Stormrider DP Pro, "lightweight" Flexon Tanker, and my "short" 183cm Head m103.
You can look at these:
1. Comparative Study of Ski Damping Technologies by Accelerance Maps (https://www.mdpi.com/2504-3900/49/1/49)... that is super easy to do, but it is hard to figure out which part of the accelerance map is important for on-snow feels.
2. Effect of edged snow contact on the vibration of alpine skis (https://rdcu.be/cAYY7). The latest and greatest, but definitely not the end of that...
Thanks, I already looked at those. Again, I contend that looking at Damping and Vibration Response is the wrong path to understanding this issue.

But I can agree that it's all moot, if people tell me it's a bad business decision to pursue this further. Perhaps the best business decision is to "just drop it" for skis, and instead solve it with the boots. Just include 3 zeppos (a.k.a. "boot boards") with every ski boot sold. "Standard" zeppo would be traditional rigid/hard, "Soft" zeppo would be the less-traditional cushy rubber that comes with some park boots (e.g. Salomon Pro Model 95 from years ago), and invent a new "SuperSoft" zeppo that you insert for your HARSHEST carbon skis---and make it standard that all 3 zeppos will be included with boot purchase, or sell them as an aftermarket add-on. I'm pretty sure that will solve it. (I actually do this---I swap Salomon "Soft" zeppos into my 130 boots...but the "SuperSoft" zeppo does not exist yet, as far as I know.)
@Noodler and @Dakine, have you ever tried that to solve your dissatisfactions?
zeppo.jpg

.
 
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AlexisLD

Getting off the lift
Skier
Joined
Jan 30, 2021
Posts
366
Location
Quebec
However, if you want, we could analyze 32 of my ski models to find correlations for the properties that I can measure without the SoothSki Tool (no stiffness measurements). I have already A/B Tested 32 of my "old" ski models on-snow, and sorted them by a metric which seems to be same as THIS metric we're talking about here...but first we'd need more precise communication to verify that we're all talking about the same thing here. Pretty sure some "smoother-than-expected" anomalies in my tests are my "lightweight" Stormrider DP Pro, "lightweight" Flexon Tanker, and my "short" 183cm Head m103.
We really need to measure you skis if you already ranked them! :)

Thanks, I already looked at those. Again, I contend that looking at Damping and Vibration Response is the wrong path to understanding this issue.

But I can agree that it's all moot, if people tell me it's a bad business decision to pursue this further. Perhaps the best business decision is to "just drop it" for skis, and instead solve it with the boots. Just include 3 zeppos (a.k.a. "boot boards") with every ski boot sold.
If you care about comfort, then I think there are better way to do it than working on the ski.

If you care about how the ski tip is engaging with the snow when it is vibrating, then you have to work on the ski.
 

Vitamin I

one-track mind
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Joined
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Posts
18
Location
NorCal
If you care about comfort, then I think there are better way to do it than working on the ski.

If you care about how the ski tip is engaging with the snow when it is vibrating, then you have to work on the ski.
I agree. But the mystery to me is I usually can't figure out which of those 2 concepts is the one that skiers are actually experiencing, because the communication is often imprecise and confusing, partly due to usage of the words "damp" and "vibrations".

What I do know is: My personal experience is that as long as the underfoot portion of my ski is planted solidly on smooth-ish snow, then if my faraway tip is ever disengaging as it is vibrating, well it's not bothering me and I'm not noticing it. Instead, what I notice is when I feel like I am getting smacked underfoot with a sledge hammer. Like when my whole ski gets deflected and my foot is briefly airborne, so it's all about resisting the deflection and holding it still and also recovering back into position. This is easy to see in slow-mo videos of DH races on ripple surfaces. AND ALSO, I notice when the less-than-sledge-hammer impact results in no real deflection, but my foot still took a blow and resisted a deflection, and the blows to my feet/knees add up throughout the day (sometimes especially for a reverse-camber ski on firm snow, which might receive all impacts directly underfoot all day long).

But I don't really understand which impacts/vibrations other skiers would like to smooth out via choice of a smoother ski model.

.
 

AlexisLD

Getting off the lift
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Joined
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Posts
366
Location
Quebec
What I do know is: My personal experience is that as long as the underfoot portion of my ski is planted solidly on smooth-ish snow, then if my faraway tip is ever disengaging as it is vibrating, well it's not bothering me and I'm not noticing it. Instead, what I notice is when I feel like I am getting smacked underfoot with a sledge hammer. Like when my whole ski gets deflected and my foot is briefly airborne, so it's all about resisting the deflection and holding it still and also recovering back into position.
Does this happens when carving or when sliding sideways?

So you are saying that the tip/tail have not much to do with this, right?

Are you talking about your ski loosing grip and starting to slide? If so, resisting deflection would be related to edge grip, right?

This is easy to see in slow-mo videos of DH races on ripple surfaces.
Can you post such video?

AND ALSO, I notice when the less-than-sledge-hammer impact results in no real deflection, but my foot still took a blow and resisted a deflection, and the blows to my feet/knees add up throughout the day (sometimes especially for a reverse-camber ski on firm snow, which might receive all impacts directly underfoot all day long).
So that would be happening during carving?

So you are really talking about confort more than performance, right?

My guess would is that damping is not that important for what you describe. To reduce the impact of a vertical impact underfoot, you need vertical compliance between the binding and edge underfoot. Without compliance, it is like hitting a sledge hammer directly. I wonder if even thin sheets of full length/width rubber can provide that? I think we could also easily create a very damp ski (e.g., with constrained layer damping added to the top of the ski) that would not exhibit the smooth ride that you are describing.
 

Bruno Schull

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Aug 24, 2017
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So just to make this whole conversation more difficult...how big are the damping/vibration control/feedback/suspension (whatever we want to call it) effects of a ski compared to the lateral and vertical elasticity of bindings? I think that bindings play a huge role in how smooth and stable a ski feels, much more than we might recognize. You can appreciate this is you ski for even a short time on a rigid pin binding with little or no real elasticity.
 

AlexisLD

Getting off the lift
Skier
Joined
Jan 30, 2021
Posts
366
Location
Quebec
So just to make this whole conversation more difficult...how big are the damping/vibration control/feedback/suspension (whatever we want to call it) effects of a ski compared to the lateral and vertical elasticity of bindings? I think that bindings play a huge role in how smooth and stable a ski feels, much more than we might recognize. You can appreciate this is you ski for even a short time on a rigid pin binding with little or no real elasticity.
I would think that it is small compared to binding/boot/liner vertical elasticity, but if people can feel a difference between skis, while using the same binding/boot/liner, then I am wrong!
 

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