 Poster: A snowHead
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Hi,
If we have the same flex for example 120, there are differences between brands?
Does anyone have experience with that?
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Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
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Brands, models, designated usage, it can vary hugely. Plus the biometrics of your legs make a big difference, sometimes you can flex a boot way more than it should be possible given it's rating. Flex ratings are really only a very rough guide.
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Well, the person's real but it's just a made up name, see?
Well, the person's real but it's just a made up name, see?
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Ok, one last time, I hope. All boots, all of them are subject to the same test. Boots are put into a temperature controlled box 22°c, a piston is placed into the boot and the boots buckled up to the average resistance available, around 30nm. The boots are then flexed through 10°, 30,000 times. The energy used but this test is then divided by 30,000 and voila, the resistance of your boots in NM.
Now the difficulty comes thus. Different type, thickness, colour and density of plastics will then react at different temperatures. Also the tightness of the boots changes the resistance and flex. So when you try a Black, Thin plastic, 13Onm boot that is tight on your foot, thus not buckled too tight, and you put a white, thick plastic boot, of certain type and high volume, this buckling tight, at room temperature (23-26°?) the boots will feel different. Therefore you'll be persuaded one way or another depending on many factors in store.
Your average ski boot plastic will get stiffer by a factor of 5ish between 15° and -15°, thus approximately the boot of a flex of 100nm could easily be 500nm during a cold January. Approximately each tooth on the boot as you buckle up tighter will increase residence of the boot by 5nm, dependant on fit and liners.
Hope that helps! xx
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| CH2O wrote: |
| Ok, one last time, I hope. |
So the engineers know how stiff a boot is, but presumably the marketing department have some input into the number that is printed on the side of the boot?
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Anyway, snowHeads is much more fun if you do.
Anyway, snowHeads is much more fun if you do.
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| Oceanic wrote: |
| CH2O wrote: |
| Ok, one last time, I hope. |
So the engineers know how stiff a boot is, but presumably the marketing department have some input into the number that is printed on the side of the boot? |
Not if the number printed on the side has to correspond to the "standard" test procedure result at 22 degC. It seems to me like the main issue is that the standard test is unrealistic when considering the temperature that people actually ski in.
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You'll need to Register first of course.
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| uktrailmonster wrote: |
Not if the number printed on the side has to correspond to the "standard" test procedure result at 22 degC. |
Has to? There is no way to enforce this.
The graph in this article shows the flex characteristics of the 130 flex Atomic Hawk Ultra XTD against the flex characteristics of the 130 flex Technica Zero G. Of course the graph is produced by Atomic, but it certainly shows that they claim that their 130 flex is stiffer than Technica's 130 flex.
https://www.wildsnow.com/22206/atomic-ski-touring-boots-hawx-2017-2018/
Last edited by You'll need to Register first of course. on Sun 21-01-18 18:04; edited 2 times in total
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Which graph? @Oceanic,
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Now edited to include the link!
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You'll get to see more forums and be part of the best ski club on the net.
You'll get to see more forums and be part of the best ski club on the net.
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@Oceanic, cheers, not so sure that would be really that noticeable.
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And edited again to include the right link!
Sorry, distracted by trying to help my wife get Eurosports Player working, no Eurosports = no biathlon on tv = very unhappy wife!
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snowHeads are a friendly bunch.
snowHeads are a friendly bunch.
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| under a new name wrote: |
| @Oceanic, cheers, not so sure that would be really that noticeable. |
Possibly not, but the graph does show that it takes 20Nm less force to flex the Technica to CH20's 10 degrees, than it takes to flex the Atomic boot to the same angle. If 130 flex = 130Nm then 20Nm out seems to be a significant difference.
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And love to help out and answer questions and of course, read each other's snow reports.
And love to help out and answer questions and of course, read each other's snow reports.
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@Oceanic, yep, point.
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| Scarpa wrote: |
| Plus the biometrics of your legs make a big difference, sometimes you can flex a boot way more than it should be possible given it's rating. Flex ratings are really only a very rough guide. |
Very valid point for me this week... was convinced that one of my boots was flexing noticeably more than the other. Went to the bootfitter who, after some exercises, pointed out I can just flex my right foot way more strongly than my left.
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You know it makes sense.
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I remember trying on a Lange freeride/touring boot meant to be a technical 120 flex and I could almost fold it in half. Then I tried on a Salomon Quest 110 boot that felt much stiffer so I bought that. I ended up selling it though as it was just too soft for my style of skiing. I ended up with the Quest max 130 which is fantastic for off piste, yet compared with my identically flex rated Atomic Redster it is a huge amount softer, way more comfy in varied terrain but I wouldn't like to drive a stiff piste ski with it.
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Otherwise you'll just go on seeing the one name:
Otherwise you'll just go on seeing the one name:
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| Oceanic wrote: |
| uktrailmonster wrote: |
Not if the number printed on the side has to correspond to the "standard" test procedure result at 22 degC. |
Has to? There is no way to enforce this.
The graph in this article shows the flex characteristics of the 130 flex Atomic Hawk Ultra XTD against the flex characteristics of the 130 flex Technica Zero G. Of course the graph is produced by Atomic, but it certainly shows that they claim that their 130 flex is stiffer than Technica's 130 flex.
https://www.wildsnow.com/22206/atomic-ski-touring-boots-hawx-2017-2018/ |
I have no idea if manufacturers all use the industry "standard" test numbers or not, but I presumed they did. Regardless, the test is flawed and doesn't take into account the vast changes between lab and snow and how different boot designs change in those conditions. Comparing flex ratings across manufacturers is very hard, especially in a warm shop.
My own boots feel totally different in a warm room compared to -10 degC out on the slopes.
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Poster: A snowHead
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@uktrailmonster, need to have a simple standard though. Could argue that the reference temp should have been e.g. 0C.
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Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
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| under a new name wrote: |
| @uktrailmonster, need to have a simple standard though. Could argue that the reference temp should have been e.g. 0C. |
Agreed. It's a rough guide and boot manufacturers and fitters know what works for their target buyers, so not really a big deal as long as you don't expect the numbers to line up across brands.
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Well, the person's real but it's just a made up name, see?
Well, the person's real but it's just a made up name, see?
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I was chatting about boot flex with my fitter back in the summer and they said the flex number on the box was just a marketing number and a rough guide. Different makers use the same number for different things and even the same maker can use the same number for different things across their range. They also said boot flex hadn't really increased in the last 10 years but the numbers had - because there are plenty of people (mainly guys) buy on ego not fit. Release the same boot with one set of graphics and a flex number of X and a different set of graphics and a flex number of X+10 and a lot of people will buy the X+10 version because it's stiffer, so better and shows how good a skier they are because they can ski a stiffer boot.
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You need to Login to know who's really who.
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FML
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Anyway, snowHeads is much more fun if you do.
Anyway, snowHeads is much more fun if you do.
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@Mjit, I assure you that @CH2O truly knows what he is talkng about... really, honestly, so your chum is, I believe talking through his toes.
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You'll need to Register first of course.
You'll need to Register first of course.
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Is it the bulb that's broke? Or the swively bit? (I googled).
[img] [/img]
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Inject exactly the same plastic into 4 different boot moulds and you will get 4 completely different flexing boots, it is not a simple as the material, but the wall thickness the engineering of the shell and even the colour to a point.
Try a boot on based on fit and see if the flex is where you want it, if too stiff go softer, too soft go stiffer, it really isn’t going to change any time soon as there are so many variables
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| Quote: |
Try a boot on based on fit and see if the flex is where you want it, if too stiff go softer, too soft go stiffer, it really isn’t going to change any time soon as there are so many variables
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Presumably this works because whatever feels right in the shop will be more or less right when you use them in anger on the slopes. ie they'll be much stiffer because of the lower temperatures but you'll also be applying much more force than just a little flex under body weight?
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You'll get to see more forums and be part of the best ski club on the net.
You'll get to see more forums and be part of the best ski club on the net.
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When people test flex in the shop are you clipped into skis? Big difference between pushing your shins against the tongue while keeping heels on the floor and having a Ski binding hold your heels down for you
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| olderscot wrote: |
| Quote: |
Try a boot on based on fit and see if the flex is where you want it, if too stiff go softer, too soft go stiffer, it really isn’t going to change any time soon as there are so many variables
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Presumably this works because whatever feels right in the shop will be more or less right when you use them in anger on the slopes. ie they'll be much stiffer because of the lower temperatures but you'll also be applying much more force than just a little flex under body weight? |
correct, you have speed momentum and a pair of skis on your feet
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snowHeads are a friendly bunch.
snowHeads are a friendly bunch.
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And love to help out and answer questions and of course, read each other's snow reports.
And love to help out and answer questions and of course, read each other's snow reports.
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@Oceanic, wrong, per CH2O above... he know about what he talks.
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| under a new name wrote: |
| @Oceanic, wrong, per CH2O above... he know about what he talks. |
Both correct in a way, the test talked about is the what is used by most BUT it is not a “standard” that they must adhere to
Too many factors to take into account, wall thickness, boot engineering, how tightly they are clipped, size of the leg, pigmentation has it for bolts innitnkr a walk mode and finally the actual durometer off the plastic
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You know it makes sense.
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@CEM, you also know of what you talk.
Surely it’s a broad comparitive indicator however, not just marketing puff.
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Otherwise you'll just go on seeing the one name:
Otherwise you'll just go on seeing the one name:
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@under a new name, biggest issue is how some plastics react at different temperatures, classic case in point was the rossignol all track pro 130, try them in the shop and they were soft as putty, get them on the hill at -10 and they were pretty solid but as they felt so soft in the store it put some people off buying them
I hunk companies dare not disclose exactly the flexes, as they don’t really know exactly, they know how one compares to another on their range and to their competitors boots which they test but take the same plastic and inject it into 4 different boot moulds form the same manufacturer and you will get 4 completely different flexing boots
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Poster: A snowHead
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@CEM, surely better than “should I buy the Explosiv 8 or 10 vs the XR or XZ?”
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Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
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@under a new name, yup marginally 
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Well, the person's real but it's just a made up name, see?
Well, the person's real but it's just a made up name, see?
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@under a new name, you also knew what was going to happen to a boot called explosion 8 or 10 
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You need to Login to know who's really who.
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@CEM, well, they were coloured international safety orange, had to be a bad sign surely?
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Anyway, snowHeads is much more fun if you do.
Anyway, snowHeads is much more fun if you do.
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I do have an intact pair of 8s, I think. TO1/2 might have binned them in fairness.
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You'll need to Register first of course.
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| under a new name wrote: |
| @CEM, well, they were coloured international safety orange, had to be a bad sign surely? |
The original ones were a slightly pinker orange
Pair of teko ski socks ( inc uk postage) to the first person ( not in the trade, and within the next 24hours) to correctly comment as to what the colour was based on 
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Something to do with TNT?
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@endoman, afraid not
I should note it was not what the manufacturer intended but I believe the designer let it slip out ( or it became industry gossip)
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You'll get to see more forums and be part of the best ski club on the net.
You'll get to see more forums and be part of the best ski club on the net.
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@halfhand, cold I am afraid
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FAQ
