SKI STIFFNESS INDEX

Is there one? Should there be one, if there isn't one now?


You could use the same scale as boots, really, 150 Pro models and race skis, 60 intermediate and soft powder skis



for example: Dynastar Sixth Sense Huge = 130,   Fisher Watea 114 = 100

and so on; it's beautiful.

Measuring the flex of a ski can actually be done in more definable way than measuring a boot. Race stock skis often come with the measured flex marked on them.

Of course, the method of measuring and reporting the results isn't standardized (I don't think), and one can imagine a variety of ways to go about it, which will produce different results. Most obviously, you can measure the flex of the entire ski, or of the tip and tail separately. The race department method generally seems to be the latter: my vague impression is that they measure by fastening the ski in the center, hanging a particular weight on the tip, and then the tail, and measuring the deflection, so: bigger number means softer, smaller means stiffer. I suppose different skis may have different flex characteristics that wouldn't be captured with a single measurement: for example, Ski A might require relatively little force to bend a little bit, but then require considerably more to bend further, while Ski B might have more even resistance. Dpending on what weight you used, you would get a different impression of their relative stiffness. And then there are a whole host of other characteristics that wouldn't be captured: dampness vs. rebound, most obviously; amount of camber; torsional rigidity; relative flex at every point along the ski (what shape the ski bends into under load), etc. etc.
 

that works so well, and would produce a useful number to identify skis, printed in the top sheet next to radius.

I could see myself using bar clamps, a bathroom scale and a few blocks of wood: 45 pounds to deflect by 8cm.

It is certainly as useful as the index employed for boots, as you said, and easier to quantify.
Edited by davluri - 11/24/09 at 8:21pm

There's a Scandinavian magazine that includes flex data in their ski tests, in addition to things like weight, running length, and surface area. The guys on TGR are fond of quoting those figures.

The interesting thing is that the test actually measures the flex at different points, rather than just listing one figure for the entire ski. So, looking at the numbers, you can get a visual representation of things like Line's "freeride flex," which is supposed to be a progressively stiffer flex from tip to tail, as opposed to other skis that are stiff up front and softer in the back.

That's the type of figure I'd love to see on all skis.

I would love to see flex numbers. But in general they seem pretty dificult to obtain.

I bet it's not as difficult as most people think.

Tennis manufacturers give flex details all the time, in addition to weight, balance, etc. Some of the big retailers even do their own tests and list those specs on their web pages. (They don't trust the manufacturers' specs because of the wide tolerances, so they test several frames of the same model and give the average measured weight, balance, swingweight, and flex.)

As long as you have the right equipment, it's just a matter of taking the time to do the tests.

 This was from a couple years ago. Best effort I know of. I am not aware of any updates. (but even searching is hard given my linguistic limitations)

http://www.friflyt.no/files/SFI_2008.pdf

Open it in Adobe & you can select specific comparisons.

And yes - this should make clear that it is somewhat difficult to represent comparative flexes as most skis do not have a single flex long their length.

The biggest problem is getting a bunch of Euro and Asian ski companies and boot companies to agree on something. (anything)

This is why boot flexes are all over the map and relative only within a given brand (sorta).

SJ

The index on the ski would cause a stiffness gap, a rush to have the baddest numbers.

I remember that set of graphs, now that you mention it. Looked like a lot of parabolas, curves in a few colors. Well everything has been done, but that didn't stick.

I would favor a number that was accurate relative to other skis. put the stressor and meter right between binding parts and push. go for the flexion that represents the ski in its natural arc.

Note the limitations and provide the testing data.

Too bad it wouldn't really reflect the different zones (would be possible though) :

Volkl Explosiv:  173, 95mm, 125-95-118, 28m, 110-140-150, 
Fisher Watea 175, 96mm, 131-96-121, 25m, 90-120-110 (just an example)

If they kept a model for a few years, it be possible to test it in the factory

Printing stiffness on skis is mission impossible. Of course unless they settle for +/- 20% or so. But I doubt that would go through with customers ;) Having printed stiffness 100 for example and in reality it could be everything from 80 to 120, would be everything but useful.
To be honest, I'm more home with xc skis, but things are even more specific with xc skis, since glide is much more important with xc skis then alpine, and so is stiffness and arc (especially for classic). With xc skis, they pick pairs (for racing service) after skis are made. They measure each and every ski, put tape with numbers, and they match them against that (of course they match those with same ptex). Race department skis are made by hand, and are much closer to each other, yet it's impossible to get 2 skis, with exactly same stiffness and exactly same lenght of arc (really important for classic skis). Normal "store" skis are matched into 3 classes (soft, medium, stiff, and sometimes extra stiff), but this can be anything in that range. So with store skis it's very possible, that your arc (where you put kick wax) can be 5cm or even more different from one ski to the other (and I'm talking about top of line store skis).
So in reality, there's no chance that this data could be already printed on top sheet of ski. On the other hand, it's really simple to measure this on your own. Ok with alpine skis there are few other things that also matter (like torsinal stiffness etc.), which is harder to measure, but basic things can be measured by any half respectable ski serviceman. But then again, for normal people it doesn't really matter, since you can't really choose skis based on this. Ski of same model from same production serie can vary more then 15-20% from another. So having perfect stiffnes on one, don't mean you will have perfect stiffness on other pair... even if it's same model.

Dave:

You're thinking too hard.....go to Mammoth........

SJ

Let's just pretend that there was this information, and it was readily available. Now what?
What, exactly would it be good for?

If a Volkl Gotama is appealing to you, would you change your mind to a Head Joe because the Head is stiffer? That would be stupid, they are different skis. I remember a certain pair of Iggy's that made the rounds on TGR a few years ago, the longest length in their stiffest flex. It kept popping up on the 'Gear Swap', always "skied twice...". It must have changed hands at least 5 times, no one that skied on it wanted it anymore. they had a flex rating back then, probably still do. I bet they sell a lot of people skis twice, first a pair for the balls, then a pair after the balls shrivel up and hide after a few runs on the MEGASUPEREXTRASTIFF Pro Model.

Skis aren't as simple as a few numbers would lead one to believe. It's more like food than stereo equipment, the end users 'taste' is what matters, not some lab test number.


(as a side note, anyone remember the 'Snow Country' magazine ski tests? They had some cool graphs... didn't mean much but they looked very scientific.)

Yes, some metrics are possible that would be fairly straight forward to obtain. However, I was speaking as a matter of fact. These data are not available in any consistent way.
Edited by tromano - 11/25/09 at 12:29pm

I don't think stiff skis are better. I am really over supa stiff skis.

Alot of people buy skis without  first having demoing that specific ski.  We have no metric for stiffness of a ski besides, the manufacturers marketing blurb and any test results and comments we might find in a magazine or online. If we had some good metric it might be easier to extrapolate and find the ski you want with out having to demo everything.

The only metric for ski stiffness I have seen are longitudinal stiffness, not torsional stiffness, which is actually alot more important in how a pair will ski.  I don't want perfection, but it would be great to have some simple consistent metric.

About half way down the page of this TGR thread are some numbers;
http://www.tetongravity.com/forums/showthread.php?t=141583

Agree that ski flex numbers certainly aren't everything or a substitute for demoing, but a consistent flex index would allow easier comparison of this aspect of different skis. For instance, based on those numbers, someone who had tried the ANT and found it too stiff could straight of the bat rule out the Mothership (despite some reviews that it is 'nimble' for its width, regardless of it being marketed as an AK straightlining rocket). It would also be a nice means to go "I liked the flex pattern of this ski, what other skis have roughly similar patterns.. Obviously a myriad of other characteristics to consider when looking at skis - a consistent base to understand flex would be useful. If I were a major ski store - I'd develop a flex index and brand it. If it became widely adopted it would be a great extension of service and means to differentiate. Win-win for everyone. Cause surely that's one of the reasons why no consistent index exists now - there's no real incentive for ski manufacturers to do it...

I don't want to come across like some dork, but why is there not a specific standardized method of measuring and rating ski flex ? For a comparative example, take a coil spring. Coil springs have whats called a standard ANSI "rate" and it's a measurement given in "lbs/inch". So if a spring is rated at 225 lbs/inch that means that it takes 225 lbs to compress that spring 1 inch. So the higher the "rate" the higher the stiffness.  So why can't skis have a measured "flex" in a similar manner? I am sure there is a good reason ski mfg's have not implamented method of standardization, juts throwing this out there for the sake of more ski knowledge on my part..

yes, there is. It won't 'help' anything.

it won't.

honest.

... and 'standardization' is the enemy of 'Marketing'. Think about that for a second.


(Sjjohnston just nailed it while I was typing that).

As Vinski alluded to, all it takes is for one group/company to develop its own standard. After some time, others will start to adopt the same standard if enough consumers make a point to ask for the numbers.

Take a look at this page about tennis rackets: http://www.tennis-warehouse.com/LC/SelectingRacquet.html. Scroll down to the sections on weight and stiffness.

In addition to the explanations about how weight, balance, and stiffness affect the performance of a racket, you also get to see two nifty pictures of the machine used to measure all three. Those who know a lot about tennis will know that this machine (and the standard for flex rating) was developed by Babolat, which started off as a manufacturer of strings, later expanding into rackets and clothing.

Now, no one says that these numbers should be used on their own to determine racket purchases. There is still a lot of play testing involved before buying. But, these numbers are very useful when it comes to selecting which rackets one might want to test. For example, after years of playing with different frames, I know I like rackets that weigh 320-330 g with a flex ranging from 60 to 65, a swing weight around 330-340, and a head size around 98-105. So, I know that, if some company releases a new model that weighs 295 and has a 72 flex, it's not worth testing because it won't be anywhere close to what I like.

There will still be plenty of people who don't know anything about their gear and just buy whatever the salesman tells them to (or whatever wins "gear of the year" in magazine tests), so marketing will always have its place. But, for those who pay attention, more info will help them determine what to try before they buy and will save them (and the salesmen) a lot of time.



(Bonus gear geek points for those who can name which racket is on the test machine in the two photos.)

Edited by CerebralVortex - 11/26/09 at 2:33am

And, what is it that makes them different, given that so much else about them is similar? Could it be the flex? And, if it is the flex that makes them so different, how is the consumer supposed to know how that? Are they supposed to spend all their time in ski shops and online asking about every single model of ski, hoping someone else has already tried them? Or, are they supposed to spend all their time trying every single ski out there to find out for themselves?

This is how a standardized measure of flex helps.

Let's say I like the Gotama and want to try similar skis. Seeing the significantly different flex rating of the Joe would tell me that it will ski very differently, so I might want to try something else instead. Perhaps the Obsethed or the P4 have a much closer flex to the Gotama, so they might be worth a demo.

Or, let's say the Gotama was too soft for my liking. I would want to find skis with higher flex numbers. So, if the Obsethed and P4 are similar to the Gotama, I would know to rule them out, moving on skis like the Joe, Goliath, etc.

In this case, having more information has saved me (the consumer) time by narrowing down the list of options to try. Demoing is still necessary to find the right one for me, but the demo process has been decreased, meaning I should find my fit more quickly and, thus, have more time to enjoy my eventual purchase.

From my standpoint is would be useful to generalize which ski to consider.  A few years ago I bought a pair of Dynastar skis that were 'great all-round skis ... super forgiving and had a sweet spot the size of an elephants rear end'.  That's exactly what they skied like for me ... an elephants rear-end, as these were waaay to soft for my weight. 

Had there been some sort of stiffness measure to help guide me with this, I never would have considered these.   To me the stiffness measure is not an absolute value, rather a comparison metric against the other equipment that's out there. A 'box' wherein one could list all the skis in the top 2/3 stiffness category, rather than go thru everything.   It simply would help me a bit in making a choice with which equipment to buy.  I'm not sure stiffness is the final factor ... for me the Rossi B2 ski - when these came out 5-6 years ago were pretty noodley, but they skied great for me. 

So for me .. what exactly would it be good for ... it's simply to be better informed and help make a choice as an informed consumer. 

OK, you guys would like flex ratings. That could be done by a shop, I run a shop, would you pay me a 'little bit extra' if I provided flex information and consultation in a ski purchase. Be honest. I'm serious here. 

People do pay more to talk with a salesperson in a shop. Hopefully he knows something. I'm sure you do, WR, just saying.

Personally I like to grab and ski and handle it, flex it. Tells me a lot.

but when a manufacturer is making a new model, I'm guessing they check the stiffness pretty carefully. that data could be stamped on the ski. I favor one number, even though that's just a start to understanding a ski.

 yeah there is a pair of 200cm retarded stiff flex iggies right now for sale on TGR id be tempted out west but would be owned at stowe.

Also most people dont take other thing into consideration about flex. Like for example how the old B5 flexed like an Ibeam but skied like a pussy cat due to the fact the sidecut made it easy to bend.

Most people ski skis WAY to stiff for them, most people I see say skiing squads just sideslip at speed down chunky hills out of control. I have always wanted to like stiffer skis but generally they just are too hard for me to ski. 

skis over the years I have felt like were too much for me, and to much for almost anyone else.

189 - 194 Squads honestly who can actually arc these thing besides hugo?
192  Elan 777 - it made the squad look like a toy, I think I may have shat myself skiing regulator johnson on these in low light.
188 Bro Super Stiff - if I weighed 200lb I could probably make use of them, they are much better than the 2 above.
183cm Atomic Sugar Daddy - forward mounting, stiff tails and lack of edge feel made this ski not fun for me at all

Ski that were surprising easy to ski despite their supposed hardcoreness 

187cm and 194cm XXl a managable freight train actually easier to ski than the normal LPs.
192cm Big Bro - felt much more at home on this than the 188 superstiff
191cm ANTS cool ski, most people could ski them.
183cm Head IM103 - in all honesty this ski flexes really stiff and has a 40 meter sidecut, I shouldnt like it, but tromanos pairs was hella fun!

I don't know if it would let you get away with charging higher prices than your competitors, but it would probably bring in a lot more business than they get once word got out that you give loads more info than them.

If I had to choose between a shop that gives me no data (have to rely entirely on salesman's word) and one that provides details on dimensions, weight, and flex (in addition to sales staff's knowledge), I'd choose the latter every time.

To get my business, the first shop would have to have a significantly lower price on something I know I definitely want (replacement for something I already have or something I've already tested).

So......

Shop (A) the salesguy says "I've skied all these skis in the following conditions and here is what they do and how they compare"

Shop (B) the salesguy hands you a little sheet that says "130-90-115, 20.2 TR, 1890 gr, 115-100-90-95-100 Nm/Cm" and you're gonna buy from shop (B) because of that?

Brilliant.

Flex numbers like the ones that I threw in above are just another thing for folks to agonize and dither about. (As if they don't have too much useless information already)

SJ

Two points I want to  make here:

1) To the extent that I'd find objective and reliable flex ratings helpful, it would not be in the context of a ski shop conversation, where the number of brands and models might be very limited by what the shop carries and has left in stock. Instead I'd use it before visiting shops - as one of the earlier posters mentioned - to try to calibrate the stiffness of skis I know well first hand with those that I don't. As a lightweight skier, I love the particular softish flex of my Dynastars, but they are about ready for replacement with something of the current generation, for my eastern soft conditions ski. If I could look up what the flex of my skis was (or if it was printed on the topskin), I could narrow my search for demo candidates by looking at skis that were in the same stiffness ballpark, without having to visit a bunch of stores that might or might not have the skis and/or staff and/or data that would help me with that particular question.

2) Sierra Jim, maybe you're just being polite to your peers in the industry, giving them the benefit of the doubt. But as a ski shop customer I can tell you that truly knowledgeable, reliable, and fully honest shops and shop personnel - at the level that you appear to exemplify - are few and far between. I'm sorry, there just aren't that many. Maybe you live in some kind of super skier friendly retail zone where every shop has someone like you on the floor all the time ... or even some of the time. I don't. The fact that you are clearly an exception to the rule is great for you and for your customers and for those of us on the board, but no one in my town is going to find many Sierra Jims in the local stores. (Sorry neighbors, but I gotta call it as I see it. You've let me down time after time.) Anyone who frequents this forum and reads stuff from you and dawgcatching and others, does some demoing, carefully watches the really good skiers on the hill, and takes time for some intelligent self-analysis about technique and gear knows WAY more about ski selection and sizing that 90% of the staff I encounter in ski shops here in New England. Even though there are three or four shops within a half hour of me, I am instead going to drive about an hour and a half each way tomorrow to bring my kid boot shopping at a store that actually knows what it's doing, has a halfway decent inventory of sizes and models, and understands that customers like me have woken up and smelled the internet when it comes to competitive pricing and knowledge acquisition. So, to answer your question, I'd pick you over the "little sheet" of paper, but given the choice between yet another kid who knows way less than he thinks he does (or middle-aged huckster who assumes without listening carefully to anything I say that he can just recite by rote from the Acme Midfat Playbook and get my respect), and a little piece of paper with some limited but at least factual information, I'll take the factual information every time.

I'm realizing now that this is a bit of a rant. I am not directing this at you, SJ; your comments here are very astute and are valuable to me. I wish your shop was in my town. So keep up the stream of excellent posts.

I completely agree with the above - there is absolutely NO substitute for excellent service from a knowledgable, experienced salesperson who offers genuine and relevant advice. Service is after all, by definition, the core business of a ski shop.

When I said a major ski store should develop their own flex index, more specifically, they would need to be large enough that they have a significant portion of online sales, and large enough that they could incur the costs of developing such an index (of course it would need to be a pretty damn good one - e.g makes sense to many, is consistent, etc) as a marketing expense. Brand it as the "(Insert ski store name here) Flex Index"...

This would benefit at least two types of customers (who are both highly involved with the decision and indeed enjoy researching before buying skis - e.g. myself);
1) Assist in narrowing down a list of skis to either a)consider and discuss with an expert in a ski store, and/or b)demo... (see qcanoe above)
2)Assist those customers in making a purchase decision based on reviews, other information - where they purchase skis sight unseen - for whatever reason - e.g. no local ski stores, no chance to demo, over enthusiasm to buy skis before a trip.....

The second example especially is where the online sales part of a ski store's business is important;

The answer to this is flat out no I would reckon.. I don't think anyone would pay more for access to a flex index...
But if it was treated by the store as a branding exercise, then it will increase awareness of a ski store's target market, provide a little extra value/service, and could hugely increase traffic on the store's website. I can imagine a whole lot of enthusiasts like myself who love 'ski gear porn' hanging out to see the release of flex ratings for next season's skis each fall... So they'd need to have competitive pricing, and still focus predominantly on offering excellent service and advice (which as qcanoe describes with SJ is undoubtedly more valuable than numbers in a flex index) in their bricks and mortar store AND online. I reckon that model could work and would be a win for the ski store and consumers who would value that kind of comparison info...
I know I'd love to be able to compare the flex of 2010 skis (I reckon five numbers anchored on a 1-10 scale works), say - Huge Trouble, Katana, P4, Mothership, etc. and get an idea of how they vary in flex. Just as a guide for one aspect of making a decision - which sits inconjunction with reading reviews, speaking to salespeople, demoing, etc.... No doubt some people wouldn't give a rats about flex numbers but I reckon there's enough people out there who would.

I'm the son of a salesman, having seen the environment he worked in and the colleagues he worked with. I know that, although there are many salesmen who are genuinely helpful, there are just as many who will say whatever it takes to get you to buy whatever they want to sell.

The best protection against such salesmen is knowledge. Knowledge is power. The more you know about what you're looking for, the more likely you are to find what really fits your needs (as long as you're honest to yourself about what you really want). This is true no matter what it is you are looking to buy (skis, cars, clothes, etc.).

So,

Shop A: trust me, these are great skis for you. You won't like any of the others as much as you will like this. I should know because I've skied on them (pay no attention to the fact that I have never seen you ski and am much bigger/smaller shorter/taller than you).

Shop B: this ski is this long, this wide, weighs this much, and has this much flex, rocker, and running length, which makes it suited to the conditions you say you are looking to ride. As you can see, it is very similar to this other ski, though one is slightly more ___, while the other is a bit more ___. From my experience, that slight difference makes this one ride a bit more ___, while this other one rides more ___. So this one will probably fit your style better, since it should make it a little easier for you to ___. (I would still try both, but it's nice to hear an informed opinion if one is available.)

Which shop would you choose?

In Shop B, I would have used the available info to rule out all the skis that were nowhere near what I like (too heavy, too stiff, too skinny), based on skis I have ridden in the past. So, I would only be asking for opinions on a very small number of similar skis that fit the range I am looking for.


Edited by CerebralVortex - 11/27/09 at 5:05am

 There won't be a universal 'Ski Flex Index' any time in the near (or distant) future, so you can save some time and energy worrying about it. The answer of 'why' is right here in this thread, if you read it carefully.