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What Skis Can Tell Us About Themselves

post #1 of 21
Thread Starter 

I have an old pair of Rossi Strato 190cm I picked up off CL a while back off for a few bucks. I pulled the bindings off last night, was looking at the Strato's in all their naked glory, thinking about them compared to more modern skis. They're pretty straight - 85-65-75 - and have a lot (about 20mm) of camber at the midpoint. I was wondering how stiff they are, and it occurred to me to lay them on a flat counter in front of me, then leaving the edge closest to me down lift the edge away from me till the ski was up on edge about 45 degrees, then compress the middle part of the ski (roughly where the boot would be) until it flattened out. In essence de-cambering the ski, roughly approximating what would happen in a turn. I was surprised at just how much resistance there was - every other alpine and cross country ski I tried that with felt like a noodle in comparison. Most of the alpine skis I have have very little camber to start with and/or compress very easily in comparison to the Strato. ( I suspect old timers might be chuckling about now. ;-)

 

I guess the action described above might tell something about the longitudinal stiffness of a ski, at least with regards to the mid (cambered) section. I tried standing the skis up and bending them pushing in the middle, but the feedback I got from that didn't seem to correlate to what I felt in the "de-camber" test.

 

Frankly I don't really have any expertise in this area, so I'd be curious what you seasoned vets do when you handle skis? Things that can help the skis tell us about themselves? Stiffness, longitudinal, torsional, tip, tail, etc?

 

One thing that did occur to me is that a ski might could be inserted into a fairly snug slot in a door or wall, (think mail slot), and then from the other end twisted. That might give some feedback about the torsional stiffness?

 

Anyway, curious to find you what can be done simply by hand, if you'd care to share.

 

Thx.

post #2 of 21
Quote:
Originally Posted by jc-ski View Post
 

I have an old pair of Rossi Strato 190cm I picked up off CL a while back off for a few bucks. I pulled the bindings off last night, was looking at the Strato's in all their naked glory, thinking about them compared to more modern skis. They're pretty straight - 85-65-75 - and have a lot (about 20mm) of camber at the midpoint. I was wondering how stiff they are, and it occurred to me to lay them on a flat counter in front of me, then leaving the edge closest to me down lift the edge away from me till the ski was up on edge about 45 degrees, then compress the middle part of the ski (roughly where the boot would be) until it flattened out. In essence de-cambering the ski, roughly approximating what would happen in a turn. I was surprised at just how much resistance there was - every other alpine and cross country ski I tried that with felt like a noodle in comparison. Most of the alpine skis I have have very little camber to start with and/or compress very easily in comparison to the Strato. ( I suspect old timers might be chuckling about now. ;-)

 

I guess the action described above might tell something about the longitudinal stiffness of a ski, at least with regards to the mid (cambered) section. I tried standing the skis up and bending them pushing in the middle, but the feedback I got from that didn't seem to correlate to what I felt in the "de-camber" test.

 

Frankly I don't really have any expertise in this area, so I'd be curious what you seasoned vets do when you handle skis? Things that can help the skis tell us about themselves? Stiffness, longitudinal, torsional, tip, tail, etc?

 

One thing that did occur to me is that a ski might could be inserted into a fairly snug slot in a door or wall, (think mail slot), and then from the other end twisted. That might give some feedback about the torsional stiffness?

 

Anyway, curious to find you what can be done simply by hand, if you'd care to share.

 

Thx.

Whatever you're trying to accomplish, at minimum, post that nonsense to YouTube and I'll bet it goes viral  ;)

 

I think the following from Hogen is the first of a six video series: "Learning about skis"

 

 

post #3 of 21
Thread Starter 
Quote:
Originally Posted by DonDenver View Post
 

Whatever you're trying to accomplish, at minimum, post that nonsense to YouTube and I'll bet it goes viral  ;)

 

I think the following from Hogen is the first of a six video series: "Learning about skis"

 

Well, that six part series is a good primer, I guess, particularly if your interest is in what can be learned from visually inspecting a ski. However, what I thought I presented clearly in my first post, what I'm "trying to accomplish", is to come to know how people learn things about skis by handling them.

 

I certainly wouldn't argue that ultimately the best way to learn about a ski is to ski it. I thought perhaps there might be an exception to Mr. Hogen's contention that it's the only other way, (as stated at the end of video six), and was hoping folks might share some of the things they do when they get their paws on a new (to them) ski.

 

Clear?

 

Nonsense?

post #4 of 21
I tried to see if I can tell the torsional stiffness in store by hold the tail between my feet and twist the tip by hand. It was surprising to find out that the difference is small enough that even beginner and advanced skis feel pretty much the same.
post #5 of 21

In the days of your Stratos you could turn your skis tip to tail and squeeze the bases together.  This would show youwhere the waist was located on the straight skis.  Waist location told you a lot about where the sweet spot was, your Stratos are back of mid cord.  

 

Squeezing them together and sliding them together side to side could also tell you if the edges were high.

post #6 of 21
Quote:
Originally Posted by jc-ski View Post

 

Clear?

 

Nonsense?

“Clearly” “Nonsense” was one response to your sticking an end of a ski into a Mailbox slit to help you torque the answers you seek out of it.  What’s next?  Waterboarding?  

 

Today’s skis are much too sophistic in material construction to manhandle with an expectation you’ll glean performance.  Sure, there are still those folks who’ll pull a ski down from a sales rack and begin a dance of twisting and flexing – but that's just an artifact owed to older design, construction, and quality.

 

Of course, if you’re into old skis and torture, Mailbox away (and have that video rolling) :DThumbs Up

post #7 of 21
Thread Starter 
Quote:
Originally Posted by jzmtl View Post

I tried to see if I can tell the torsional stiffness in store by hold the tail between my feet and twist the tip by hand. It was surprising to find out that the difference is small enough that even beginner and advanced skis feel pretty much the same.

 

I guess for torsional stiffness a fairly significant amount of force is needed to have an impact. That's why I thought effectively clamping the tail end, (mailbox slot would be a crude way to do that), while twisting the tip end, (perhaps with the help of a little leverage - a couple boards clamped perpendicular over the tip area like wings should do it), might be a useful experiment, using different skis, to give a relative feel for the torsional stiffness of each. Carpenters use (or use to) something similar on one end of a twisted 2x4 to straighten it out before nailing it in place when framing.

 

Quote:
Originally Posted by Stranger View Post
 

In the days of your Stratos you could turn your skis tip to tail and squeeze the bases together.  This would show youwhere the waist was located on the straight skis.  Waist location told you a lot about where the sweet spot was, your Stratos are back of mid cord.  

 

Squeezing them together and sliding them together side to side could also tell you if the edges were high.

 

That's the kind of thing I'm talking about - thx for sharing.

 

No one else? Even if only for old skis? Love to hear more.

post #8 of 21

Whang the tail of the ski against a hard floor while holding onto the waist - feel for how much vibration travels through it-  tells you where it lives on the lively/damp scale. 

post #9 of 21

I'm an old guy.  I like to bend the skis and see how much longitudinal flex they have and where they are the most stiff, I put the tails on the flow and hole the tip and press at the waist/binding area, judging by both force applied at the waist/bindings and the shape of the curve and amount of deflection.  I also grab them at the waist with one hand and at the tip with the other hand and see how easy the are to twist and how much I can twist them.   Then while holding them in one hand and give them a sharp rap with the other hand and feel the vibration travel through the ski.  Be careful not to cut your hands when doing the twisting thing (been there, done that:o). 

post #10 of 21
Quote:
Originally Posted by jc-ski View Post
 

 

I guess for torsional stiffness a fairly significant amount of force is needed to have an impact. That's why I thought effectively clamping the tail end, (mailbox slot would be a crude way to do that), while twisting the tip end,.

 

JC you will be amazed how little force is actually required to twist a ski.  You have a ski that does not hold well on hard snow?  Try this on them, you may see why.  

post #11 of 21
Thread Starter 

Again, thx folks for sharing some of the things you do. A few comments below...

 

Quote:

Originally Posted by cantunamunch View Post
 

Whang the tail of the ski against a hard floor while holding onto the waist - feel for how much vibration travels through it-  tells you where it lives on the lively/damp scale. 

 

I've tried that with a few different skis, but I don't seem to be able to induce or pick up on significant vibrations. May well be doing it wrong, though.

 

Quote:
Originally Posted by Ghost View Post
 

I'm an old guy.  (1) I like to bend the skis and see how much longitudinal flex they have and where they are the most stiff, I put the tails on the flow and hole the tip and press at the waist/binding area, judging by both force applied at the waist/bindings and the shape of the curve and amount of deflection.  (2) I also grab them at the waist with one hand and at the tip with the other hand and see how easy the are to twist and how much I can twist them.   (3) Then while holding them in one hand and give them a sharp rap with the other hand and feel the vibration travel through the ski.  Be careful not to cut your hands when doing the twisting thing (been there, done that:o). 

 

As to #1 above, even I can get something of a relative feel for how longitudinally stiff skis are by doing this. For example, yesterday I handled a pair of 2007 Rossignol Scratch BC WRS skis. I am likely not appreciating the subtleties of the flex along the length, but in general they felt much softer than anything else I have. For people who might buy used skis it seems like this simple procedure might yield some useful feedback as to whether a ski is "skied out" (if that's important). I know the Scratch BC skis are intended to be lighter and softer for touring and powder.

 

When I try #2 I can induce a little twist/deflection at the tip of some skis, but not much. I suspect it's a "learned feel" thing. How much twist are you guys able to induce, and is there anything additional you can share about how to interpret things?

 

#3 works better for me to induce vibrations I can definitely feel, but again I'm not sure exactly how to interpret them. A seasoned ear can tell how tightly strung a tennis racket is by banging the stringbed with the frame of another racket, and listening to the pitch. Certainly you can tell which of two rackets is strung relatively tighter by listening for the higher pitch (frequency). With skis are you paying attention to the amplitude of the vibrations, or the frequency, or both?


Edited by jc-ski - 11/3/13 at 11:57am
post #12 of 21
Cmon guys... mailbox ski twist test? Attach wood wings for leverage?

Turn your troll radar on.

As for me... I always ask shops or eBay sellers to let me demo down a soapy slip and slide set up in the stairway. And I use a paint mixing rig to test for vibration dampening.
post #13 of 21
Quote:
Originally Posted by justruss View Post


Turn your troll radar on.
 

 

Nah, we know jc-ski by now.   For someone who only started maybe 5-6 years ago his level of enthusiasm for both old and new is absolutely wonderful.   We also know that he's very much not afraid to experiment and figure things out on his own.       The sport needs more joiners like him. 


 

post #14 of 21

In that case, my apologies to the OP. Feel free to mailbox-test your skis. But I don't think you're going to be able to consistently tell anything useful about the ski from that kind of torsional test. 

 

It's common to read experienced folks posting things like: "I hand-flexed in in the shop, but I was surprised by TK once I finally tried it on the hill." And that's testing for longitudinal flex, which is almost assuredly easier to feel. Given the interplay of materials, shapes, the rest of the equipment (bindings, boots), etc... any testing of the ski that doesn't involve skiing it has got to be essentially useless at best-- and misleading at worst. 

 

Waste of time. 

post #15 of 21

^^^^ I'll go the other direction (of course): I'm surprised by how much I can figure out about a ski by just hand flexing it, assuming I also have access to the dims, including rocker, and know what it's made of. Not saying I can tease out all the details of handling, or grip, but I'm seldom flaberglasted when/if I ski it. No, I'm not suffering from megalomania, but this isn't rocket science, either. First, ski brands have characteristic feels and patterns of handling across model years. There's a typical Rossignol feel/handling that's quite distinct from a typical Kastle feel/handling, which is way different than a typical Blizzard feel/handling. Market differentiation, same reason we know there's a BMW feel that's different from a Toyota feel. 

 

Second, where a ski flexes stiff or soft will determine a lot about how it initiates or handles crud or whatever. I find fronts and backs more informative than middles, personally. Thus a Blizzard front, which tends to be stiffer relative to its middle than most brands, will produce a typical security in bad snow at the cost of initiation ease, which can then be tweaked by stuff like Flipcore. Stockli's have slight softer tails relative to their middles than most brands, which gives them that progressive handling in the last third of the turn compared to say, Heads with VERS, which likes to launch you. Thus third, make further mental adjustments for depth of camber or shape of rocker, and then fourth, make another for metal or carbon or basalt or whatever material tends to produce a particular snowfeel. Rossi's are damp by corporate fiat because of the VAS; kevlar or basalt or metal frosts the cake. So think along these lines, flex in a few places, and you'll be ballpark. Period. 

 

Seriously: Those out there who've demoed/owned/tested a lot of skis: When was the last time you fondled a ski, knew a bit about it, or its brand, and then skied it and was absolutely off base about it? Happens every once in a while, but waaay more often, you're,  "Uh huh, yep, OK that's about what I thought, give or take." Or, "Uh huh, in line with what I expected, but improved since last year for X."

 

Caveats: This is all driven by mental comparisons. So don't think twisting, mail slots aside, helps much unless you do it all the time, to every ski you fondle, to build up a base of comparison. Since a ski twists a lot less than it flexes longitudinally, the differences between two skis are gonna be pretty tiny. Good luck on that one...

post #16 of 21

Yeah, but Beyond-- how much of that is because you just happen to know what a certain brand tends to feel like, and a certain line within that brand tends to feel like and then can work some subconscious magic vis-a-vis flex and expectation? 

 

I think it's hard to separate that, or to test what you'e really getting input from. Cover the top sheets and hand flex ~20 skis, write down what you expect in few key areas in a 1-10 scale. Now ski those skis with the topsheets covered and write down your results in the same areas from 1-10. I wonder how closely the two sets of scores would line up from ski to ski? 

 

So yeah, I think if you take the Blizzard Flipcore line, and you're familiar with it, and you know what the reviews and peers tend to say and you know the stats (dimensions, materials) AND then you hand flex them-- you might be able to glean something additional from the flexing. Or you might be able to trick yourself into thinking that's what you're doing. At the least you'll probably get a sense that a Bushwacker and an older Bodacious are going to respond differently! 

 

Or maybe some people really can divine the differences with a high degree of accuracy.

 

Sounds like we agree about the mailbox/torsional flex... good luck with that one! 

post #17 of 21

Well, you're suggesting a thought experiment in reliability testing. Obviously, expectations and previous experience figure into any evaluation. Not just "subjective" measurements, either. Even using a micrometer. All part of intra and inter observer error. But does that = "tricking?" Does the fact that we have biases mean that any measurement that includes those biases is useless? 

 

Umm no. Let's disregard the last 20 years of neurobiology that indicates "hunches" and systematic biases often represent connections between the prefrontal cortex and the limbic system, such that we are drawing on success or failure of previous algorithms to hone our efficiency in solving the problem on the table. Let's also disregard entire new schools of statistics that find discriminatory power increases when prior outcomes and expectations are included. After that, we still know that brands do have characteristic shared design parameters and production specs that produce a brand "feel." That's deliberate, as you know, and is driven by corporate marketing decisions. When a brand changes it's design goals in a big way - Salomon comes to mind when Atomic acquired it - the alteration of brand feel and performance is often a big deal. Everyone notes it.

 

So I'd argue back that figuring previous knowledge into a current hand flex, isn't subconscious magic, it's just one way we humans make current evaluations more efficient, and predictions more accurate. My hunch that 2015's Rossi E88's will retain a damp feel, have a fairly light weight, with fairly soft tips and modest rocker that don't overpower the skis's carving ability, is worth betting on. And it isn't "cheating," since it's simply incorporating previous data that has proven correct. Companies generally strive for product predictability as long as it's associated with profit. Which is why a Big Mac is designed to taste the same anywhere. 

 

The counter argument goes something like this, if you wanted to make another thought experiment: Correlate various ski attributes against each other. Cluster the results. The resultant group membership will have no significant overlap with those groups simply formed by brand. Interesting conjecture, but I'd doubt you'd find anyone else on these threads that'd buy it.

 

Fact is, while there will be some overlap, given the sheer number of products out there competing within each width range and skier demographic, Blizzards will be more like other Blizzards than like Rossignols. Where it gets interesting is if you compared brands that had common engineers or designers or production facilities. No accident that Blizzards and Volkls and Nordicas share some qualities. Say they comprise a larger cluster different from the Rossignol and Dynastar one, which used to include Salomon too. So I really don't see how this means that it's trickery to flex a Volkl, or ping it, or whatever, and glean a family resemblance to other Volkls. The flex will be one of the intra-group correlations. 

 

As far as flexing by hand, meh. Some people don't know how or where to flex a ski anyway, so it's like kicking a tire. Others do. Someone here, Sierra Jim, maybe, say back when that he could flex a ski and tell most of what he need to know about it. I believe it. Same argument as mine here, unstated. But consider that Fri Flyt has been published well-respected flex charts for years now, using weights hung at various points along the ski and measuring deflection. Used paint cans originally, I recall. And that's the same deflection you or I try to produce in a store. Only instead of measuring cm of deflection, we estimate differences in resistance to muscle force between the ski we're pushing at and the one next to it. Or last week. Obviously more sources of error. But some people are pretty good at estimating force. Moreover, if you can hand flex the front 1/3 of a Mantra and then do the same for a Prophet, and not be able to consistently note that the Mantra required more force, get thee to a neurologist. If you can then ski the two, and not note that the Mantra has different handling characteristics than the Prophet that are partially attributable to the differences in front flex, get thee to a ski school...;) 

post #18 of 21

I love this stuff, Beyond. 

 

And I surely don't think it's cheating in the universal sense of the word to incorporate all the things you mention. Nor do I suggest actually ignoring contemporary neurobiology (I'm somewhat familiar with some of those neurobiologists and their work for professional reasons). Hell, I flex skis by hand in shops and before skiing. But it's mostly curiosity, and I don't give it much weight in my predictions. 

 

I was only suggesting that I think it's difficult to determine whether you're really getting much additional information from hand-flexing vs. the non-flexing input (whether read or other). 

post #19 of 21
Quote:
Originally Posted by beyond View Post
 

Well, you're suggesting a thought experiment in reliability testing. Obviously, expectations and previous experience figure into any evaluation. Not just "subjective" measurements, either. Even using a micrometer. All part of intra and inter observer error. But does that = "tricking?" Does the fact that we have biases mean that any measurement that includes those biases is useless? 

 

Umm no. Let's disregard the last 20 years of neurobiology that indicates "hunches" and systematic biases often represent connections between the prefrontal cortex and the limbic system, such that we are drawing on success or failure of previous algorithms to hone our efficiency in solving the problem on the table. Let's also disregard entire new schools of statistics that find discriminatory power increases when prior outcomes and expectations are included. After that, we still know that brands do have characteristic shared design parameters and production specs that produce a brand "feel." That's deliberate, as you know, and is driven by corporate marketing decisions. When a brand changes it's design goals in a big way - Salomon comes to mind when Atomic acquired it - the alteration of brand feel and performance is often a big deal. Everyone notes it.

 

So I'd argue back that figuring previous knowledge into a current hand flex, isn't subconscious magic, it's just one way we humans make current evaluations more efficient, and predictions more accurate. My hunch that 2015's Rossi E88's will retain a damp feel, have a fairly light weight, with fairly soft tips and modest rocker that don't overpower the skis's carving ability, is worth betting on. And it isn't "cheating," since it's simply incorporating previous data that has proven correct. Companies generally strive for product predictability as long as it's associated with profit. Which is why a Big Mac is designed to taste the same anywhere. 

 

The counter argument goes something like this, if you wanted to make another thought experiment: Correlate various ski attributes against each other. Cluster the results. The resultant group membership will have no significant overlap with those groups simply formed by brand. Interesting conjecture, but I'd doubt you'd find anyone else on these threads that'd buy it.

 

Fact is, while there will be some overlap, given the sheer number of products out there competing within each width range and skier demographic, Blizzards will be more like other Blizzards than like Rossignols. Where it gets interesting is if you compared brands that had common engineers or designers or production facilities. No accident that Blizzards and Volkls and Nordicas share some qualities. Say they comprise a larger cluster different from the Rossignol and Dynastar one, which used to include Salomon too. So I really don't see how this means that it's trickery to flex a Volkl, or ping it, or whatever, and glean a family resemblance to other Volkls. The flex will be one of the intra-group correlations. 

 

As far as flexing by hand, meh. Some people don't know how or where to flex a ski anyway, so it's like kicking a tire. Others do. Someone here, Sierra Jim, maybe, say back when that he could flex a ski and tell most of what he need to know about it. I believe it. Same argument as mine here, unstated. But consider that Fri Flyt has been published well-respected flex charts for years now, using weights hung at various points along the ski and measuring deflection. Used paint cans originally, I recall. And that's the same deflection you or I try to produce in a store. Only instead of measuring cm of deflection, we estimate differences in resistance to muscle force between the ski we're pushing at and the one next to it. Or last week. Obviously more sources of error. But some people are pretty good at estimating force. Moreover, if you can hand flex the front 1/3 of a Mantra and then do the same for a Prophet, and not be able to consistently note that the Mantra required more force, get thee to a neurologist. If you can then ski the two, and not note that the Mantra has different handling characteristics than the Prophet that are partially attributable to the differences in front flex, get thee to a ski school...;) 

Got any links to flex data?

The calibration of the wrists when doing the twisting is dependent on experience.  Say you see a ski on the wall but don't know anything else about it, other than the shape.  Just about anybody will be able to tell the difference between a ski that twists like The old Rosi Bandit and B1 and a ski that twists not so much like an old Volant McG.  Telling the difference between a Fischer SL and an Atomic SL won't be so easy (although the ping test will distinguish how they will feel on the snow).

post #20 of 21

Here's the site (Norwegian) that does the flex tests: http://www.friflyt.no/

 

The most recent one I've come across in translation is: http://www.tetongravity.com/forums/showthread.php/231045-Fri-Flyt-SFI-overview

 

They seem to come out semi-annually, I've downloaded some back to about 2006, but haven't looked specifically for more recent than 2011 (above). 

 

Agree about SL's because IMO there's a lot less variance in racing gear than in rec gear. But I've hand-flexed/fondled Rossi and Head SL's, for instance, and can feel a difference. Can't really distinguish Rossi and Dynastar. OTOH, I've never found twist that helpful simply because most skis have much less torsional flex than longitudinal. So a smaller range means much smaller differences. Yeah, I like pinging too. Volkls sound a lot like they feel...

post #21 of 21
Thread Starter 
Quote:
Originally Posted by cantunamunch View Post
 

Nah, we know jc-ski by now. 

 

Thx for that. Silly/crazy? Maybe? But...

 

 

Speaking of Internet video, clearly there are some who feel, with "modern" skis, anyway, that handling is of little benefit. But for those who don't feel that way it might be interesting to compile a little library of instructional videos showing how to flex, "ping", or otherwise test a ski by hand, and how to interpret the test results. A demo with commentary, perhaps using a few different skis to illustrate points.

 

We could create a channel and post vids. Any interest?

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