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teeheehee... I guess i'm on a regression curve. Will be touring valley bottom stuff around Stewart this year with plywood and metal door hinge home brew ghettoworks copies of alpine trekker/securafixes. Got a bunch of new skis to test that have solly alpine rental binders. Putting the mid speed quads into bull low and go slow is my new m.o. Should be good training for the dynafit days.
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Originally Posted by LeeLau
I got to spend some time with Daron Rahlves and the Atomic version HERE.
No to distract from the topic here but kind of ski is Daron holding?Quote:
Originally Posted by Flexon Phil
It seems implied (and/or maybe assumed by many TGR-folk) that because the SHIFT meets TUV certification, a touring boot will release from the SHIFT as though it's alpine boot in an alpine binding. But what evidence do we have that this is true?Quote:
Originally Posted by Alkasquawlik
Jeff Campbell wrote his doctoral thesis on the biomechanics of binding release/retention using an ASTM F504-05 (2012) apparatus, and found some very interesting results with touring boots in frame bindings, including those with an adjustable toe adjusted to the manufacturer's specs. Here's a talk on the topic: https://www.youtube.com/watch?v=XZ7Y5EzCiEg
And some interesting quotes from his thesis, available here: https://digital.lib.washington.edu/r...dle/1773/38177
Quote:
In our previous study, all 10 AT boots released appropriately from one alpine binding model (out of the eight models studied). Two bindings did not release appropriately with any AT boot. Such a large variation in binding performance indicates that boot-binding systems are very sensitive to how they interface and how their constraints change across different boundary conditions.
Features of the single binding that passed testing with 100% of the boots have been shown to be predictive of lower release torque and displacement in the statistical analyses reported in this study. Acceptable release performance was achieved for only 40% of the AT boots, or less, in the seven remaining alpine bindings. Some of these bindings had some features in common with the most successful binding, but no other bindings shared the specific combination of features with the highest performing binding that released appropriately with all AT boots tested.
AT boot-alpine binding systems are highly sensitive to the interactions (e.g. combinations) of boot-binding features that can have a multiplicative affect on release torque. Sometimes the effects of these interactions can be reversed by changes in boundary conditions, as is the case with static and mechanical AFDs. Overall, bindings with mechanical AFDs ranked as the lowest performing bindings with AT boots (Table 7).
A governing paradigm in the ski industry is that a boot will function properly in a binding if it “fits”; and, it is therefore assumed that the fit of AT boots in alpine bindings should be correlated with proper function. AFD contact pressure measurements were able more accurately quantify how well a given boot fit into a binding toe piece. Higher AFD contact pressure values are predictive of a tighter fit and higher frictional forces; lower AFD contact are predictive of a normalized fit resulting adjustable toe height or boots conforming to international standards (ISO-5355-2012). AFD contact pressure was a strong predictor of release torque for the Pure Twist release but its’ effect was much smaller in combined loading releases (Front Preload Twist, Rear Preload Twist). Table 3.7 indicates that the highest performing alpine binding and the lowest performing binding both had nearly equivalent AFD contact pressure. In other words, AT boots fit into both the highest and lowest performing bindings equally well but performed significantly differently. These results show that the interaction of AT boots and alpine bindings is significantly more complicated than just fit and AT boots fail to perform properly in bindings that can be adequately adjusted to fit the larger linear dimensions of AT boots.
Has there been serious standardized testing with different AT boots with tech fittings with the Shift? Can you or the design engineers share those data? Because the SHIFT has a mechanical/sliding AFD, I'm skeptical of the release characteristics with AT boots, especially non-WTR.Quote:
The worst load case for mechanical AFDs occurs in Front Preload Twist releases, when a preload is applied to the fore-body of the ski significantly increasing the pressure between the soft AT boot sole and AFD. As a lateral load is applied to the ski, softer AT boot soles stick to mechanical AFD as the binding moves away. During this phase, the spring-loaded cam in the toe piece, which normally controls release torque, is overcome. Here the boot settles into a local minima 5-10° past the point when an Alpine boot would have released (Figure 3.10). Internal friction retains the boot in the ski and the boot must overcome a second energy barrier to finally release. This final energy barrier is simply a function of the internal friction of the system and is no longer controlled by the spring-loaded cam intended to control the release torque.
NB: I don't know Jeff Campbell, and I have no affiliations with any outdoor company. Just asking the question.
I ski the Lange freetours in the bc, and I think the plastic is to soft to last years in the resort with an alpine binding.
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Pretty sure only wtr and regular Alpine boots are certified for proper release in these bindings. I think there are a bunch of wtr compatible tech fitting boots right? I don't believe I have seen any claim these will release properly with ANY touring boot.??Quote:
Originally Posted by auvgeek
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MNC - is that supposed to include straight touring boots or not? Obviously it includes hybrid models like the s-lab, Cochise, etc. but not sure beyond that.
My understanding based on Cody's first post is that the SHIFT is MNC, which includes ISO 9523 aka most touring boots.Quote:
Originally Posted by Skidog
I'm not saying it won't work, and I'm happy to be proven wrong. I'm absolutely not an expert in this field. My point is we should be very skeptical -- just because a binding is TUV certified (which tests to ISO 9462/13992) and a touring boot fits does not mean it will release appropriately with anything except an alpine boot, as I understand it anway. And, as Dr. Campbell mentioned in his talk, the Vermont calibrator results in a high percentage of false positives compared to the ASTM F504 apparatus/spec he used, so you can't really take your boots & skis to a local ski shop to test them.
Additional info from wildsnow comments:
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Originally Posted by Jeff Campbell
So the question for Cody and the designers are did you guys test to ASTM F504 with ISO 9523 alpine touring boots? Or did you stick with the more relaxed ISO 9462/13992 certification?Quote:
Originally Posted by Jeff Campbell
The makes and models of the bindings used in the study is witheld, right?. Too bad.
On my adrenalins the boot soles came very close to the frame in one spot. I bet with enough downward force the sole could have been caught in the frame. I filed the frame down.
Yeah, it is. But you can piece things together reasonably well with a careful reading of Ch3 of Campbell's thesis because he documents the features required for release, the degree to which they're correlated to proper release in each scenario, and which bindings had which features. Obviously, I don't feel comfortable guessing at this publicly, not when knees are at stake. But even if you can't piece together the differences between bindings, you can at least rule out all bindings with sliding AFDs because they all performed the worst.Quote:
Originally Posted by daught
It's surprises me that Campbell's research hasn't gotten much traction anywhere but wildsnow. Seems really important for all the dentists who want to run one boot.
Meh, each TUV reliability standard is narrow enough to not take any as the gospel for consistent release. As soon as you brake the rotational axis off the X, Y or Z axis the standard looses reliability. God forbid you add some sort of variable axis to the mix.
Why I love my LooksQuote:
Originally Posted by XavierD
Whoa. This is some next level binding nerdery. I like it. Though I may not be 100% accurate on my answers because ISO and TUV certs are pretty new to me in all reality. After all, our original concept for the binding was "pin up, alpine binding down"...not "conform to multiple ISO standards". But anyways, I did just have a pretty thorough conversation with the head of the SHIFT project and binding project marketing manager this week while in France, so this was my understanding of it all.Quote:
Originally Posted by auvgeek
First, the MNC definition means that it is TUV certified for use across the two major boot certifications, touring and alpine. It also is then certified under the two sub-definitions of touring boots, WTR and GripWalk. So essentially, the binding is certified for use by TUV for the four major adult norm boot forms. The only boots left out are CSD (compact shell design boots like the new Hoji boot and the Salomon X-ALP) and junior boots.
As far as binding certs go, this boot was tested and certified under the Alpine norm, ISO 9523.
In regards to your other comments about the thesis and Jeff's studies...yes, there is some fishy shit going on with bindings and boot interfaces in regards to TUV certifications. I was enlightened on some pretty interesting independent studies on some new hot bindings and the inability to get the replication of standards multiple times. I'm not gonna say who or what because there is literally potential legal blowback by saying that stuff publicly (hence why Jeff held back the makes and models as well) but the point is...boot/binding interfaces aren't tested enough by binding manufacturers and TUV. That being said, this is exactly why Salomon went for the MNC label...meaning, they tested their bindings against the four major boot forms. That being said even more...the skiability tests prove to be the most reliable in my opinion. We tested bindings that met certifications but had prerelease issues. We then fixed those issue and have what we have today, which is a binding I trust a friggin shit ton.
Oh and lastly, I tested this past week bindings in touring boots with sliding AFD plates and without sliding AFD plates. Regardless of safety and releasability, the difference in skiability and feel was so much bigger than I thought. Which leads me to believe that sliding AFD's, when adjusted correctly, do have a decent impact on releasability.
Hey Cody, thanks for the reply -- really appreciate it. I don't know much about the certification processes myself; just starting to dive into it. Like I said, I don't work in the industry at all. And you're right -- there seems to be serious implications and blowback to objective testing outside of the TUV certs. Hopefully Jeff's work spurs more research, design, and discussion around this issue.
All your points are very interesting and well-taken. Especially your trust in the Shift and the difference in feel of sliding AFDs.
But, to point out the obvious, you're a big guy who charges hard and I assume you usually run your DIN/RV quite high. So your needs and desires might be a bit different than a small lady who needs the binding to release at a DIN/RV of 6 in touring boots while she's falling forwards and twisting. Not arguing; just saying.
Hope you have a great, injury-free season.
Oh for sure, I can only judge against my standards, which are related to being 190 lbs, maxing out the din and trying to straightline through mogul fields...which is a good test, just a different test. But I will say, I would nearly guarantee these would release more consistently and safely than any tech toe binding on the market in the situation you're describing. Of course TUV wouldn't say so, but I do, simply from seeing it and skiing it.Quote:
Originally Posted by auvgeek
Lastly, yeah, was interesting to test the STH2 with and without sliding AFD's and touring boot soles. I honestly didn't think I'd find that much of a difference but it was quite drastic. It's truly incredibly how elasticity in a binding not only increases safety, it skis far better.
...and why I'll very likely be buying a pair to replace the Kingpins.Quote:
Originally Posted by Alkasquawlik
A rubber AT boot sole IS after all there to provide friction on whatever surface you happen to be walking onQuote:
Originally Posted by Alkasquawlik
Besides that extra friction for walking (compared to a plastic DIN surface) the rubber sole of an AT boot absorbs and releases energy as we ski which IMO/IME causes pre-release
so I will always go 1 DIN extra on the heels when using an AT boot in a Frame AT binding
I notice my Vulcans have 4 hard round grey nubs in the sole which possibly were put there to help make release more reliable ??
Yes.Quote:
Originally Posted by XXX-er
Oh for sure, I can only judge against my standards, which are related to being 190 lbs, maxing out the din and trying to straightline through mogul fields...which is a good test, just a different test. But I will say, I would nearly guarantee these would release more consistently and safely than any tech toe binding on the market in the situation you're describing. Of course TUV wouldn't say so, but I do, simply from seeing it and skiing it.Quote:
Originally Posted by auvgeek
Lastly, yeah, was interesting to test the STH2 with and without sliding AFD's and touring boot soles. I honestly didn't think I'd find that much of a difference but it was quite drastic. It's truly incredibly how elasticity in a binding not only increases safety, it skis far better. Better edge grip, less chatter, better ski flex...was kind of blown away while at the same time realizing it made a ton of sense.
You are saying the STH2 with sliding AFD skied better, right? Interesting that binding manufacturers insist on keeping static AFD's on their high DIN "performance" models . . .Quote:
Originally Posted by Alkasquawlik
I think I'm going to print out the last few pages of this thread and put it by my bedside table. In case I can't sleep tonight, this should do the trick.
Quote:
Originally Posted by auvgeek
To these two points. Read about the TUV testing methodology. Read about the actual ISO standards and how they were developed (it's actually documented in working group papers). ISO certifications are quite conservative. It will give you some insight into what Cody said, why it is true and why the ISO standards and TUV testing usually lag actual developmentQuote:
Originally Posted by Alkasquawlik
With a touring boot, vibram sole it did.Quote:
Originally Posted by gregL
Hey Cody,
How can i get a pair for free? i have an unpublished blog with no readers. and I once reviewed a product i purchased from an online vendor. I'd be keen to trying these out and share my opinion with no one in particular. I can be discerning and use helpful phrases like "the pointy things stabbed by finger when i was testing their springs for coffee filtering." and "the heel is not shaped like other heels." I think this will serve Salomon well. probably much better than Blister Gear Review. What say you?
Off-topic:
Love the tweeting/campaigning you're doing with Jessica Morse. Keep up the good work.