WildSnow Tech – Onyx and Dynafit Jaw Pressure

Post by WildSnow.com blogger | April 9, 2010      

G3 sent this info over. Their engineer did some testing on production bindings, Onyx and Dynafit Vertical ST. This should interest any binding geeks out there, but especially those who might have trouble staying in Dynafit bindings and feeling compelled to ski them with the touring lock engaged.

Note, I’m getting a sore throat from repeating that the vast majority of skiers have no trouble skiing Dynafit bindings in alpine mode WITHOUT locking out their release, so don’t get all hot under the boot soles about this. But randonnee binding retention and pre-release are still issues that do affect bigger, stronger skiers on heavy gear (usually on harder snow) so we feel it is fair to keep bringing it up and sharing information such as this.

Onyx Dynafit jaw pressure comparison

Onyx and Dynafit toe jaw forces, click image to enlarge.

According to the G3 engineer, who I have no reason to doubt since our own tests show an obvious difference between the bindings (following is paraphrased): “The obvious difference in jaw pressure is not only due to the springs we use, but more so due to the geometry of the jaw arms and their pivot points. You can see that a Dynafit binding goes “overcentre” (pops open) at around ~63mm (in order to be able to be not too wide when fully opened). The G3 toe goes overcentre at around 67mm (which is a range that the toe never really gets to). This is one of the reasons why you have to open the G3 toe.”

The graph highlights 3 key jaw widths (defined as distance between the toe pin tips):

· Ski ~58mm – which is the width that the pins are at when you’re engaged in the binding, this is dictated by the standardized (we pray) boot fitting

· Release ~61mm – the approximate width that Onyx and Dynafit release occurs at (meaning the boot tech fitting easily disengages from the binding toe pins)

· Step in – ~64mm for the onyx… Dynafit measures at 66mm for the various ST models we have in the WildSnow shop

According to G3 engineer: “You can see from the curves between ski and release that the area below the curves (which is energy absorbed) is much larger for the Onyx. In the opinion of G3, this is why people can ski the onyx much harder in icy conditions without locking the toe out. We did this testing with an instron type pull tester equipped with an LVDT displacement transducer, so I’m very confident in our results.”

N = Newtons, the metric unit of force (1 pound = 4.45 Newtons)

mm = millimeters for displacement ( 1 inch = 25.4 mm)


Please Enjoy A Few Suggested WildSnow Posts


64 Responses to “WildSnow Tech – Onyx and Dynafit Jaw Pressure”

  1. Carl April 9th, 2010 9:44 am

    This test is worthless without posting the DIN adjustment on each binding, with this big of difference in release force the binding are either not set the same or one does not test in spec. closing force should be directly proportional to release torque which is defined by the DIN standard, both G3 and Dynafit say their bindings meet this standard so something is missing in this picture.
    As an engineer and former ski tech this information is misleading at best and wrong at worst, I would like to see an automated torque test using the same boot and same din settings that could measure peak force and energy to release out of each toe piece.
    I am also very interested in more data as I am a big strong skier that has had pre release problems and just bought FT12s to get maximum retention and if the onxy will hold me in better (in a controlled test) i would switch

  2. kirk April 9th, 2010 10:06 am

    ummm carl… there are no din adjustment settings on dynafit toe pieces that I am aware of, and I don’t think g3 has any either in the toe?(never used the onyx) its a one hat size fits all kind of deal.

  3. Lou April 9th, 2010 10:11 am

    It is simply a test to determine how much force it takes to open the toe. The theory is that what causes the occasional Dynafit pre-release is the toe opening up due to side forces. To me, the graph makes a great deal of sense, though it might be a bit obsessive for most of us who don’t have any issues with staying in the binding.

    As for pre-release, I have to say that if I had that problem with a binding I’d switch to something else immediately if the problem wasn’t resolved. It seems weird to me that a person would keep skiing a binding they were coming out of. Good way to get badly hurt. And skiing with lateral release locked out is also a pretty good way to get hurt and help your orthopod afford an aircraft upgrade.

  4. Ken April 9th, 2010 10:57 am

    Note that not supplying the full range of values for both the x axis and y axis leads the reader to believe the difference is greater than it actually is. Very sneaky and misleading for some. If you want to demonstrate differences, plot those curves and show the whole thing.

  5. Christian April 9th, 2010 10:59 am

    Carl: Also – the torque test must be around the axis parallel to the ski length.
    Lou: I just bought the Mustagh Ata.SL 187. A light ski. Released while skiing blueish snow/ice after about half a run. I skied vigorous short turns until the release, and was very pleased with the feel – so the release took me by surprise, and I ended up with a broken rib. I took the ski and boots to the local dynafit shop (next door to the dynafit importer) – they found no faults, but set my binding to 10/10. When I released they were adjusted to 8 vertically and 9 horizontal. (I am 85kg). They said that skiing technique affected the release more than with other bindings. I am not sure what kind of release this was, as everything happened so fast. What is clear to me is: with the Mustagh ata sl the problem is far less than with the coomba or the snowwolf (a narrow ski). Maybe due to ski flex or binding attachment? If this was a typical pre-release (i.e. the fornt piece opens), it can indeed happen with lighter gear. I kept skiing on the skis through easter and had no more releases – my skiing was vigorous…but not extremely so.

  6. Christian April 9th, 2010 11:01 am

    …I forgot: The shop also moved my binding a little closer to my boot – i.e. closer than recommended.

  7. Randonnee April 9th, 2010 11:17 am

    Manufacturer marketing-propaganda. Such is unfortunate, whether it is shovel ‘tests’ arranged by a manufacturer, or this problematic ‘graph.’

    My understanding was that raising the front lever of a Dynafit toe increases the force required to cause release. That is similar to what is described by the above.

    The usually ignored component of Dynafit toe-release is the width of the ski waist. Wide-waist skis on hard snow would seem to cause a greater force on hard snow that would release the toe.

    The new Dynafit FT12 and ST Pro bindings that I am using do not require that I raise the toe lever in order to stay in while skiing downhill. I think that this is quite an endorsement considering my 100+ kg weight and considering that wet Cascade snow that I ski often refreezes to be quite hard.

  8. Jonathan Shefftz April 9th, 2010 11:31 am

    So the Onyx jaw pressure pretty much steadily *increases* as the boot toe moves off center (whether as a result of the heel unit starting to release laterally or as the result of a exogenous shock to the boot unrelated to the release function), whereas the Dynafit jaw pressure pretty much steadily *decreases* as the boot toe moves off center.
    Umm, so, which relationship is better?
    And anyone with a background in alpine downhill bindings know what the graph would look like?

    Also, although this would be helped by some tick marks on the graphs, looks like Onyx has about 18% more jaw pressure with boot toe centered (i.e., jaws fully closed) and about 71% more jaw pressure with boot toe at the release point. Total area underneath the graph is about 43% higher for the Onyx. (As Ken pointed out, the 100% figure cited by G3 is valid only if closing force above 100N isn’t counted.)

    By the way, for those who think the older-style Classic/Speed/Comfort toe is better than the Vertical, better track down some old stock, b/c I’m pretty sure this year’s Speed toe is just this year’s Vertical combined with the old Speed base plate, the old Speed toe lever, and different color for the mounting plate. (The Dynafit website is out of date, since the current Speed toe has all the little subtle differences that distinguish the 09-10 Vertical toe from prior years – I just confirmed this now with a side-by-side comparison between the older Speed, the 09-10 Speed, the 09-10 Vertical ST, and the older Vertical ST.)

  9. Lou April 9th, 2010 11:37 am

    Rando, it’s understandable to see this as propaganda, but it matched my own independent but crude testing, so I figured it was adequately vetted so I published. Even so, how important this is in real world use is the question.

    And sure, locking the Dynafit into touring mode increases the “release,” but it’s not designed to do that, not calibrated, and depends on the flex of the ski topskin and the toe unit binding parts to allow any sort of release.

    ‘best, Lou

  10. Lou April 9th, 2010 11:39 am

    Christian, moving the binding closer will raise the release tension a bit, but it can also cause your boot to press against the binding when the ski flexes, which can easily cause you to throw a shoe. I’d be careful of that.

  11. Lou April 9th, 2010 11:43 am

    BTW folks, I should mention that higher jaw pressure is not always better. If you miss and get your toe pins imbedded in your boot plastic, higher jaw pressure will cause more damage to your boot than lower, and can damage your boot quite quickly. Dynafit fittings should have more metal around them to prevent this. The “Quick Step In” type fitting is a bit better, but still could provide more boot protection.

  12. Cam April 9th, 2010 12:16 pm

    Cam from G3 here. I just wanted to address some comments and thank everyone for the discussion. The genesis of this post came from Lou’s desire to look at jaw forces (see his post on shimming), and objectively look at the differences between different bindings. I asked him if he’d like some help, since we have a bit more sophisticated test rig than he does in his shop, and some of distances and forces are rather hard to accurately measure. The other reason was in a previous post, readers asked for objective test results. A university prof once told me that if you can’t measure it, you can’t talk about it….to which I agree wholeheartedly. We can all see that it’s the interpretation that gets sticky!

    The intention of sharing the plot, which didn’t come out of the blue from G3, was to help Lou out with a study he already wanted to do. I also asked Lou to check the results before positing, since I didn’t want things to come across the way Randonee feels it does.

    Ken, you’re 100% right…and starting the graph at 100 was a complete oversight on my part…I did make sure i got the right operating range for the x axis, but y axis values were set to scale automatic which gave rise to the screw up…thanks for noticing as I didn’t. I’ll supply Lou a revised plot later today, and I should have had the plot checked by a second person. No sneakiness or smoke and mirrors intended…just a busy engineer who’s sleep deprived due to rocking his newborn to sleep at 3AM, and then dawn patrolling. 😉

    Carl, you bring up a good point which is that the complete energy absorbed in a lateral release does depend on the heel and the toe working in combination. this plot only shows half the story. The intention was to objectively show the toe’s contribution which is where Lou was heading after his shimming post.

    Jonathon, thanks for clearing up the energy estimate as per ken’s

    Hope this clears up the intention of the study (which we did as a side project to help out lou), and the error that I made. Engineering departments are very different to marketing…if it was propaganda I should have had it in three D with dancing bears and sparkles in the graph.

    thanks again for all the responses and the perspectives.

  13. Lou April 9th, 2010 12:45 pm

    Thanks Cam, it’s bold of you to step in. Everyone, please be nice, it’s tough getting industry folks to show up here and take the risk of commenting. MORE, Cam took the time to see how much force the toe jaws required for opening, as a direct consequence of and to help with my previous post about modding the Dynafit as an experiment to increase toe jaw force. This is NOT some kind of marketing stunt. How much meaning it has in real life skiing is of course a question, but I think it’s instructive at the least and may be important.

    As for the issue of heel unit contributing to force absorption, yes it does. But the type of pre-release some folks are experiencing with Dynafit appears to the best of my field testing to be an opening of the toe jaws from fairly direct side force (perpendicular to the long axis of the ski), so my whole thrust with this geek out, and the whole reason Cam went to the trouble to measure things, is to get some ideas of the binding’s response to this type of force.

    It’s not a twisting force that would involve the heel unit, simply direct force applied to the toe jaw wings (perhaps with a bit of twisting thrown in for good measure, when people are doing this in real life.)

  14. Cam April 9th, 2010 2:17 pm


    you’re quite right on the mechanism of pre-release for tech system bindings. Since Tech system bindings rotate roughly about the toe pins to release laterally (as opposed to a more conventional alpine binding which rotates about the centre of the heel) it makes their release less sensitive to tip loads (and more sensitive to tail loads). DIN settings only address the torque (force x distance) that will give rise to a release, and thus it’s quite possible to generate large lateral loads at the rotation point (toe pin) when a load is transmitted to the ski in the region of the toe pin (The torque setting doesn’t change so when you have a small lever you need a large force before it releases). The extreme of this situation is when you load the ski directly through the pivot point, and are not able to create a twisting release since the lever length is zero. This is where pre-release can occur since the graph above shows the load that will open the toe jaws at.

    Tech bindings are inherently more complicated than conventional bindings due to the linking of the toe to the heel mechanism to create the lateral release. Up to everyone to decide whether this matters for them or not.

  15. Randonnee April 9th, 2010 2:31 pm

    Lou I do appreciate you interests and efforts. However I stand by my statement -marketing- “In the opinion of G3.’ No representative of Dynafit is included in this discussion.It is probably unlikely that a company as large and as successful as Dynafit would debate engineering in this manner, in my view and observations thus far.

    Cam you are very welcome for my comment, thank you. This comment is pure marketing- ‘According to G3 engineer: “You can see from the curves between ski and release that the area below the curves (which is energy absorbed) is much larger for the Onyx ~2x more energy absorbed for each lateral release. In the opinion of G3, this is why people can ski the onyx much harder in icy conditions without locking the toe out. We did this testing with an instron type pull tester equipped with an LVDT displacement transducer, so I’m very confident in our results.” ‘

    The scientific method is not even within sight here. That quote uses the word, “opinion.”

    What kinds of comparisons led to the above statement? What widths of ski waists, weight of skier, and on and on. Then are intangibles- I can walk on skis or ski downhill in a fashion that will make anything I have been on release. Sorry, cannot see scientific methodology here, blatant marketing.

  16. tOM April 9th, 2010 3:11 pm

    While I’m not an engieneer, it seems obvious to me the testing should have been done on the toes ONLY of each binding to isolate the forces exerted by the toe jaws at various opening widths. This was intended to be separate from ski width, din setting, skier weight, style ect…It also appears obvious to me that given the toe jaws effect on release with the differing pressures between the G3 and Dynafit that the Onyx heel must move laterally with less force than the dynafit for the same din release setting,(if i assume correctly that toe + heel resistance when < ski boot twist forces = release). I clearly see the science in the test as executed. Maybe my panties aren't in a wad since I ski both bindings?

  17. SB April 9th, 2010 3:56 pm

    Cam’s statement seems like basic physics, not marketing. If the energy required to open the front pins is greater on their binding, then it will take more energy input from the user to create a front pin activated pre-release. Since the geometries where the measurements are taken are identical between the two bindings, an educated extrapolation would lead one to beleive that pre-release would be less likely in one case vs the other regardless of how wide the ski is or how heavy the skier is or how brutish their technique is.

    When an engineer says “in my opinion” it is often formulated from facts and calculations, which he doesn’t want to spend the time going over. I do it all of the time. It doesn’t mean its marketing. It may be inprecise usage of language.

    PS. I have no interest whatsoever in G3 success with this product. I’m just an engineer and find Randonee’s responses mysteriously combative.

  18. Jonathan Shefftz April 9th, 2010 3:59 pm

    Cam, what about the tension value as a function of pincer spread — do you think this has any significance, in particular how with Dynafit it’s an inverse relationship?
    (And why haven’t you come up with an engineering solution for an automated rocking motion for soothing your newborn back to sleep?)

  19. John April 9th, 2010 4:57 pm

    I performed a little experiment by placing a low durometer elastomer between the toe lever and the base plate. This changed the release dynamics as I expexpected. First it slightly increased overall release force, but second, and more importantly, it increases the time interval for a release. This helps offset the stochastic nature of of the loading of a binding by intoducing a spring that is slower to react, because it absorbs energy, the time to force the jaws over center is greater. Maybe a simple elastomer, properly shaped, could be produced as a simple plug and play device.

  20. Lou April 9th, 2010 4:58 pm

    We’ll, perhaps we will get some word from Dynafit. You never know.

  21. Lee Lau April 9th, 2010 6:51 pm

    DItto this comment

    PS. I have no interest whatsoever in G3 success with this product. I’m not an engineer but find Randonee’s responses mysteriously combative.

  22. Lou April 9th, 2010 6:56 pm

    Cam just shot me over his new chart that should be a better presentation of the data. I replaced the old with the new. I also made a few tiny text edits as the quoted text was more of a casual email than something ready for publication. Apologies for blasting it out without more editing. Too busy around here with Denali prep I guess (grin). I was awed today watching Louie upski with his pack loaded to 60 lbs. Mine was a measly 30, but it felt like 60 for some reason (grin).

  23. Randonnee April 9th, 2010 9:53 pm

    It would be reasonable to say such-and-such value was obtained in a bench test and leave it at that. But it becomes something else when ideas such as consensus of users and statements that one is better are injected.

    Well, fellas, there is just more to it than arbitrarily applying a force in isolation, a force unlike the designed use, to 1/2 of the binding system, and measuring it. Yes, one may extrapolate of course that one releases as such on a bench- does that carry over to use of the entire system? Perhaps, but to make such a claim then the entire system and a complete test reasonably covering pertinent variables needs to be explained. Many variables are ignored in this discussion.

    This is a fascinating topic, in my view, but it seems not nearly as simple as this limited scenario. The Dynafit binding suspends the boot, does it not, therefore the weight of the skier is suspended, one factor, and then other forces are added. Just this it would seem makes this complex. And other variables as well.

    This is perhaps more than springs and force. John’s comment above is very interesting. I think the original concept is modeled on a smooth curve, if I get it John suggest something to change the shape of that curve?

    Sorry again, but it still sounds like a partial explanation of an uncertain of value test that is validated by “hey an engineer did this- don’t ask too many questions.” I do not claim to be qualified in any special fashion but it seems to be incomplete thus inconclusive. Therefore it seems to be marketing when a claim is made that one works better. It would be fascinating to learn of more of the many considerations in engineering a Dynafit binding. Perhaps my comments then would make no sense, I cannot say. Or perhaps Priopietary research and information will not be shared in this fashion.

    In the past I have been less than pleased with some Dynafit gear. I am thrilled at the real improvement in Dynafit equipment in recent years, in my use, and feel that some real engineering improvement went into that. What I say is opinion, not science, but I am able to recognize science.

  24. Art April 9th, 2010 10:00 pm

    …mysteriously combative is right.

    Good scientific methodology involves isolating and studying as many variables as possible and drawing conclusions from the results. When it’s not possible to isolate all variables and their effects under all scenarios, one must form educated ‘opinions’ in order to use the learned information. When months, or years of research goes into something it is virtually impossible to communicate completely the results in a couple of sentences without doing wrong by someone (ask climate scientists, nutrition scientists or high energy physicists!). It seems to me that a more measured response to this study would have been to ask for more detail or clarification rather than simply labeling it marketing — but that takes more effort than dismissing it as bad science.

    …and sometimes as an engineer or scientist it’s just more diplomatic, not to mention humble, to say “in our opinion” instead of “your just wrong, we’re right”.

  25. Bar Barrique April 9th, 2010 10:33 pm

    Good discussion, while I am a fan of Dynafit bindings; it is good to remember that their (Dynafit) boot offerings became much better after they licensed their binding tech to other boot manufacturers. So it is reasonable to expect that competition in the production of this type of bindings will bring us similar benefits, like (hopefully) the next generation of lighter bindings.

  26. Matt April 9th, 2010 10:45 pm

    I haven’t had issues with skiing pre-release on my Vertical STs, but I have had issues with skinning pre-release. Always seems to be with crappy technique (edging on hard / icy snow or twisting the ski when it’s trapped under snow). Annoying, but interesting to see that even with the toe locked there is releasability.

    (I’m 185 cm and 75 kg)

  27. Matt April 9th, 2010 10:47 pm

    Cam, is G3 really only 13 people? It’s going to be tough to crack that lineup for my dream job.

  28. Randonnee April 9th, 2010 11:06 pm

    Matt I have pondered this as well. Perhaps the rotating heel while skinning enhances easy instant toe release. That is one factor it seems. My solution has been to drop the heel elevation when this occurs and that seems to help- or just concentrate.

    After so easily releasing the toe in touring position when skinning I have later tried to release while standing on flat ground. It is very difficult for me to intentionally twist out of the FT12 toe in touring position when flat, but I have managed to do it. With the FT12 toe in skiing position, I have been able to intentionally release it while watching and observed what seemed to be a nice elastic motion of the pins moving out of the holes.

    There is also that potential variable of icing the pin holes. I try to clean, stomp, and rotate until it seems on visual inspection that the pins are well-seated.

  29. Lou April 10th, 2010 6:58 am

    Again, to try and state is simply:

    A few people have told me they have trouble staying in the Dynafit binding while skiing downhill without the toe locked. They described a type of pre-release, which they even demonstrated at will, that appeared to be a result of the toe opening up due to side force on the toe wings.

    I did some crude experimentation with this, and Cam at G3 agreed to do some more precise measurements of this, yes, isolated part of the system. Cam had some opinions about this based on his experience, measurements, and testing by a large group of backcountry skiers who he gets feedback from.

    The idea here is to stimulate discussion, and enjoy or work with whatever conclusions you guys can get from this — especially those of you who might have some pre-release problems.

    As for this being marketing, sure, Cam works for G3 and is loyal to his company. But he’s also an honest, standup guy. Anyone reading his ideas should be able to easily separate the small amount of his loyalty induced opinion from the greater whole. I could have edited that out, but it seemed totally reasonable to me, and still does.

    Yes, the Onyx has more jaw force. That is a fact. Cam’s opinion is that more jaw force makes the Onyx better for more aggressive skiing. But reality strikes. Hundreds of thousands of people do fine on Dynafit bindings without locking the toes for their descent, so my bringing this issue up is indeed not a big deal to most of us. BUT, it is nonetheless interesting to some of us, so thanks everyone for the excellent comments. Just be nice.

    Yes, it would be nice if someone thanked Cam for taking the time to do this test, and for offering up his opinion as an engineer.

    You guys are probably all tired of hearing marketing spew. Well, here is a company that lets its engineer speak. I think that is terrific. Thanks Cam and G3.

  30. pcatt April 10th, 2010 7:41 am

    An interesting discussion from all parties. I have both a 3yr old Comfort and a 2010 FT12. To me there is a world of difference in these two bindings. I have problems with the pre-release in the Comforts (weight ca. 100 kg) but I am not sure that this has to do with the side forces mentioned here. Most of my pre-releases occurred when I got rocked back and rocked forward and then back again from variable snow conditions. My thoughts were that this rocking movement caused pressure on the toe and hence the toe piece would open and if one was rocked backward I would pre-release. Consequently, I started locking down my toe piece. Almost all the people I tour with who use older Dynafit versions lock down their toes as well. In fact, around where I ski, Austrian Alps, I haven’t seen too many people that don’t.

    In the FT12 I have had no such problem and ski without any fear of a pre-release, although they are mounted on a pair of Manuslu’s so I try to avoid any icy conditions.

    In any case, I don’t think it is any coincidence that Dynafit’s binding improvements both in ease of use (toe pieces incredibly easy in any conditions to get into, heel piece easy to switch with any type of ski pole) and robustness are a result of G3 coming onto the market. So thanks G3 for making Dynafit a better binding!

    And thanks Cam for braving abuse and contributing to this piece. Your analysis is informative and makes for a good discussion. In no way, would I interpret your comments as “marketing”. It is good that you differentiate between scientific test results and the conclusions which you draw from it which are your educated opinion. Worrisome would be if you stated your conclusions as fact, which you clearly did not.

    I would love to try a G3 but found them surprisingly bulky and a little on the heavy side compared with the newer Dynafits. The newer Dynafits have become so easy to use that most of the ease of use advantages of the G3 have now been made redundant. So I guess I will wait until they get their weight down.

    And lastly, I couldn’t agree more with Art that it is far better to start asking questions before one throws around accusations.

  31. Jonathan Shefftz April 10th, 2010 8:16 am

    I definitely appreciate Cam’s quantitative tests and his participation here. The selection of jaw pressure is definitely an important factor in how these bindings work, and I find the differences between the two bindings in this regard to be very interesting (albeit not compelling in either direction). So, yes, thanks Cam!

    I’m not sure though how much thanks we owe to competition from G3 for recent changes in Dynafit design. The Vertical series came out in Fall 2006, and the FT12 came out in Fall 2008. The Onyx debuted in Spring 2009. Perhaps some of the Dynafit changes were in anticipation of the patent running out, but Dynafit doesn’t seem to have made any changes directly in response to competition from the Onyx.

    “Most of my pre-releases occurred when I got rocked back and rocked forward and then back again from variable snow conditions. My thoughts were that this rocking movement caused pressure on the toe and hence the toe piece would open and if one was rocked backward I would pre-release. Consequently, I started locking down my toe piece.”
    – So are you saying that you resorted to largely eliminating the safety release function of your bindings before you tried simply increasing the release settings? (Or were you already maxed out at 10 when you experienced the prereleases?)

  32. jerimy April 10th, 2010 8:18 am

    I think this is a great start to getting the whole picture, thanks Lou and Cam.

    I will gladly volunteer my time and effort to get to the bottom of this, just need G3 and Dynafit to supply me with some sample bindings :biggrin:

    The experiment needs to be done with a boot in both the toe and heel units. I have a few ideas about how to do the experiment, I just don’t currently have all of the necessary tools at my disposal. I will try to put my thoughts on paper along with pictures and video.

  33. Lou April 10th, 2010 10:59 am

    I heard a rumor that the Onyx is only the beginning, and that another binding is in the works from G3. Cam, any hints?

  34. Randonnee April 10th, 2010 11:40 am

    :devil: Gee, to say that I am ‘mysteriously combative’ is like saying I weigh…225. Both are facts, or understatement :angel: . Thought we were discussing a topic. My words can be provocative…in either direction. Really, intent is just to debate. Can you all imagine when I broke my new FR10 ski while *ascending* how I lit up the phone line while discussing the replacement and how fast it would arrive? :blink: Really I do not try to get anyone’s BP elevated, it just comes naturally! :angel:

  35. Lou April 10th, 2010 12:12 pm

    Like I always say, Dynafits are like a smart, beautiful woman, in that both the bindings and the girl require intelligence and athletic ability on the part of their companion. The question is, where do Onyx fit into that equation? That is what we are ultimately trying to figure out here at WildSnow.com 😆

  36. pcatt April 10th, 2010 2:12 pm

    @Jonathan – “- So are you saying that you resorted to largely eliminating the safety release function of your bindings before you tried simply increasing the release settings? (Or were you already maxed out at 10 when you experienced the prereleases?)”
    My settings were maxed out but I don’t believe the release settings are a major part of the release problem. Rather it seems from my limited experience that the pressure placed down on the spring causes them to open up, in a similar way you can release on the uphill if you forget to lock them. Interestingly, the FT12 doesn’t seem to have this problem. Maybe it was just a question of putting in a beefier spring. I find it interesting that a lot of skiers in Austria lock their Dynafits as well. More from practical experience than anything else. There are no accident statistics covering this but generally speaking most people like to lock down their toes here and are more worried about the consequences of this in an avalanche rather than they are about the safety release.

  37. David April 10th, 2010 7:41 pm

    I am appreciative of Cam and G3 (and wildsnow) for sharing some info in this way.

  38. Jon Moceri April 10th, 2010 11:38 pm

    I’ve now skied the Dynafit TLT binding over 500,000 vertical feet this season and the only pre release I had was coming to a sudden stop in the lift line. While I am only 145 lbs or so, I ski steep and difficult terrain at Crystal Mountain, Washington without any worries about my Dynafit bindings. I ski them in the unlocked position.

    I am thinking that many skiers out there are just skiing too hard. Hey guys, get some lessons from some really good ski instructors. I skied the Berner Oberland with Mike Hattrup and was complemented on my skiing. It’s just a matter of the right ski coach and lots of downhill skiing experience. I’m no athlete. Cancer as a teenager and stunted growth. But your ski is a powerful tool. Learn to use it wisely.

    I’ll be guilty of saying the emperor has no clothes, but the majority of backcountry skiers I have met are great uphill skiers, but terrible downhill skiers. Come on guys. If you only ski down what you skin up, you are never going to become good downhill skiers. Buy a lift ticket once in a while and put in 29,000 vertical feet in a day. That is from the summit of Mt. Everest to the Indian Ocean in a day.

    The joke going around my Alpine/Backcountry skiing group about the Turns All Year group is…”365 turns all year” or ” 24,000 feet a year is pretty good, for a beginner”.

    BTW, I just mounted new Dynafit TLT’s on last years K2 Anti Piste Telemark ski. It is the same ski as this years K2 Coomback, and I love the the ski. Much softer than the Coomba and the extra rise in the tip, makes it float so much better.

    Thanks to Louie for such a nice write up on the K2 Coomback while in New Zealand.

    Also, I am using the B&D ski leashes this season. Quick, easy and reliable. I recommend them.

  39. Christian April 11th, 2010 11:02 am

    Jon: sometimes you need to ski hard to get your edges to hold. I started to ski when I was 1 1/2,race when I was 5. I currently ski apprx 100 days a year. Most of my prereleases have been in slopes, but it has also happened to me in the backcountry. When icy, I tend to not keep my skis on the edge , but rather apply the edging in a short quick burst in order to change direction. When racing we described the technique as “quick edge glide to the pole”. I only prerelease when doing short turns and using this technique. Yes, I can avoid it – but I prefer to use my whole technique quiver…and I hate skidding.
    This weekend I skied down a 35 degree backcountry slope with mixed slush and windpack and lots of bumps doing quite speedy gs-turns – no problem. That is the way it usually is – so I keep buying dynafit.
    I had the k2 coomba for a while. On that ski I got a lot of prerelease. Might be that I compensated for its softness with technique…? It was nice when it was soft.
    Anyway: I really like this thread. It is great that G3 and Cam is providing this info. Off course it is marketing…but it is ok marketing. I will probably try out the Onyx if I decide to go for a wide rando-gear (i.e. +11cm waist). I’ll ask the G3 and dynafit importer here (same company) for advise.

    Lou: Regarding moving the front-binding forward. I am not quite sure what “throw a shoe” means…? Is it “destroy the shoe/boot” or that that the pressure to the back of the boot will cause it to release? (or something else)

  40. Toddl April 11th, 2010 1:01 pm

    Randonnee or others: what is the difference between the dynafit ST and the ST PRO. I looked at the dynafit site, but they seem to be the same. Is that true?

  41. Jan Wellford April 11th, 2010 1:32 pm

    The ST Pro is white. That’s it.

  42. pal April 11th, 2010 1:44 pm

    I have been skiing Vertical ST’s and Scarpa Spirit 3 boots for the last year and a half and have been quite happy with the performance and no pre releases. Recently however I noticed a change in the binding behavior. When pressuring the toe downward as in a turn on firmer snow the toe piece wings expand and then click back in when pressure is released, no actual pre-release yet but rather disconcerting. I can reproduce the problem by stepping on the boot with it in the binding at home. Skiing with the toe lever up one notch stops this problem, but I don’t really want to ski that way I narrowed down the problem to the right boot by trying different boot/ski combination’s. A close inspection of the boot shows a very slight deformation of the toe socket, could this be the cause? Anyone have this problem? I saw a thread on tgr to a similar problem with Spirit 3 boots. I have noticed that Dynafit boots have a more substantial pin socket. Any ideas, or is the boot toast? How about a shim like for an F1 boot to support the toe from moving down?

  43. Colin April 11th, 2010 1:51 pm

    The Dynafit FT12 is prone to total binding failure in the toe piece due to the new “carbon” plate. Make sure you check daily the toe pieces for any sign of cracks around the toe piece screws.
    The FT12 has a new plate that has been reconfigured to save grams and as a result puts additional stress on the toe piece under and around the mounting screws. Think “lever” effect.
    I will post some photos from a toe piece that split in two after only 30 days of skiing.
    Until I get that post out, I highly recommend all FT12 users to switch to speed or comfort type plates and get rid of your “carbon” plates. This can be done without re-drilling.
    Dynafit will/should switch the plates for you without questions….I also believe they will be eventually forced to cancel the FT12 beginning with a recall.
    Not only is the new plate design at fault, but the actual toe base piece is made of weak metal (lots of oxidation and thin).
    Also, the toe piece design is not able to handle the forces of an expert skier on fat skis.
    Shame on Dynafit for rushing out the FT12 which is weaker than the previous/current DIN 10 models. The FT12 is a marketing gimmick and was not properly engineered. I predict lots of other incidents of binding failure among “freeriders” using the binding for the high performance skiing the Dynafit company is claiming it is intended for.
    Again, this is a warning to all FT12 users to switch out your carbon plate….and again….
    SHAME ON DYNAFIT for selling a piece of crap that is prone to failure. I repeat here: check your FT12 daily for signs of cracks in the toe piece metal plate around the mounting screws. A failure will cause the toe piece to split resulting in instant pre-release which can end up seriously injuring or killing a modern freeride skier on high perfomance boots (Factor e.g.) and super fat skis (115-140 mm under foot).
    Photos and full post to come later in the week.

  44. Colin April 11th, 2010 1:54 pm

    also, if you are experiencing pre-releases with the FT12 it is maybe because a micro crack is forming in the toe piece metal plate and causes the jaws to open during certain forces caused by normal freeride skiing.

  45. Lou April 11th, 2010 2:22 pm

    ST and ST Pro are essentially the same binding. Lou

  46. Jonathan Shefftz April 11th, 2010 3:41 pm

    Colin, even if your thesis is correct, then why in this SECOND season of the FT12 has the failure you experienced not been more widespread?
    And why do you “recommend all FT12 users to switch to speed or comfort type plates” instead of the Vertical ST plates?

  47. Lou April 11th, 2010 5:29 pm

    That is quite a rant Colin. Looking forward to checking out your photos. First I’ve ever heard of that failure mode, and I know a LOT of people on FT12s….

  48. Jonathan Shefftz April 11th, 2010 5:42 pm

    “Colin, even if your thesis is correct, then why in this SECOND season of the FT12 has the failure you experienced not been more widespread?”
    — I just remembered, the FT10 was out for two full seasons before the heel unit release setting was upped to 12. So that’s four seasons thus far for the toe plate design.

  49. Jack April 12th, 2010 12:36 am

    Lou, an exceptional post once again with quantification and thanks to Cam for the data. Great thread. I really appreciate the follow up.

    Lou, have you observed many Europeans Dynafit users descend in tour mode?

    pal, I’ve experienced a similar problem with my Spirit 3 / ST.

  50. Lou April 12th, 2010 7:01 am

    Jack, I indeed have paid attention to that and noticed that some do and some don’t, like here. As for myself and folks I mentor, most of us descend with locked bindings only when ski loss would mean certain injury or death, otherwise we leave the binding unlocked so we can actually get a safety release if necessary, especially in an avalanche.

    Bear in mind I’m speaking about average sized folks such as myself.

    Larger guys sometimes need to ski with the binding locked, but definitively not as a rule, as folks such as Randonnee have found. Much of this depends on style of skiing, and the binding model, as well as how the boot/binding interface functions with your own personal combo of boot/binding models.

    Main thing is, if you don’t have problems with pre-release, skiing with the binding locked is usually ridiculous and just asking for injury. And if you do have problems with pre-release, it’s a good idea to look at the whole system before simply locking out your safety release as a solution.

  51. Lou April 12th, 2010 7:03 am

    Pal, boot toe sockets can be defective. Sometimes they lack proper heat treating, or are not shaped correctly. Since you isolated the problem to one boot, I’d say it’s the boot not the binding. But I’d have to look at it in person to be sure.

  52. Cam April 12th, 2010 11:58 am


    Thanks for asking the bindings 201 question, as the differences in the curves is very important in terms of energy absorbtion. The bindings 101 interpretation of the plot is just that one curve is higher than the other, but your question highlights HOW the energy is absorbed.

    The lower curve absorbs most of the energy in the early part of the curve between ski and release, the upper curve absorbs more energy in the latter portion (and actually more the in early portion than lower curve too, but the question was just about rising vs falling rate curves).

    What’s siginificant when it comes to retention is the ability for the binding to return to neutral in dynamic situations.One unfavorable condition for prereleasing from bindings is chattery icy conditions where it is not a single load or disturbance that causes the release, but a buildup of smaller perturbations that can eventually cause a release. (ie. the first chatter could bring the jaws slightly open, and the second a bit further, etc..) Anyhow, the significance is that the tending towards closed while allowing some elasticity is key in dealing with chattery-repeated-rapid loading situations like this. Simple physics define that the acceleration that an object experiences is proportional to the force acting on it, so if a jaw is slightly open a higher force will return it to neutral faster than a smaller force.


    regarding future bindings, my son isn’t the only thing that keeps me sleep deprived 😉

  53. Walt April 12th, 2010 11:12 pm

    Are you actually saying that the FT10 and the FT12 use the same toe plate? That explains everything then. I had the FT10’s and sold them halfway through the first season because of pre-release issues. Then I bought the FT12’s and noticed maybe a little improvement. But maybe that was all in head as I never released from the rear anyway. Dynafit heels work. It was 99.8 % of the time a front release. Now, I just ski with the toe in tour mode. (which I don’t think is that bad because it will release if torqued hard enough.) I always thought Dynafit used stronger springs on the FT12 toe piece. Are you really sure the toe pieces are the same?

  54. Walt April 12th, 2010 11:40 pm

    The reason many bc skiers have no problems at all with the dynafits is either they are just simply shorter (so less torque) and lighter than bigger skiers or they fit the category that I see a lot in backcountry skiers regardless of size. These people are just frail and weak. (even if they weigh 200 lbs) They usually have adequate if not even good endurance, but they could be tied to their skis with twine and still stay on. They lack power and strength. A skier should be able to squat at least close to double bodyweight and have the explosiveness to have at least a 30″+ vertical leap. I know a lot of kids who never lifted weights in their lives when tested can do this because they are powerful skiers and got they way by skiing strong. They threw away the small chainring on their mountain bikes, skiied 4000’+ runs at high speeds without stopping, stuff like that. I not advicating being a gym rat. I’m just using the squat as a gage of power. But there are a million ways to get strong. But Lynsey Vonn spends a lot of time in a gym, so there must be something to it. But if you are one who just likes to make lackadaisical turns through the powder in between bong sessions, dynafit bindings are for you. Or perhaps, your smaller stature just allows you to get away with using them.

  55. Lou April 13th, 2010 7:30 am

    I’m not doing bong sessions these days, but I guess my turns could be called lackadaisical — perhaps I need a medical pot perscription to make myself complete? :angel:

  56. Lou April 13th, 2010 7:49 am

    Walt, as far as I know the FT 12 and ST 10 toe units are the same other than the cosmetics of the base plate. I have no reason to believe different.

    The small amount of increased maximum release tension (from 10 to 12) is created by three things: a washer in the rear spring barrel, a possibly slightly stronger lateral release spring, and stiffer vertical release springs.

  57. dave eckardt April 13th, 2010 11:04 am

    People of normal weights blowing out of Dynafits probably aren’t skiing well. They need to go back to their roots and ski in a tele binding a little bit so they can remember how to stay centered over their pressured ski.

  58. John April 13th, 2010 11:41 am

    I ran some torque tests on 2010 FT-12 toe pieces with tech inserts. (charts will follow next week, as I am traveling the rest of this week). A stock FT-12 toe piece releases at approxiamately 25 ft. lbs. of torque. The opening rate curve is about a 40 degree slope. Release occurs at about 4 degrees of rotation. This correlates with the heel peice rotating about 35 degrees (45 being over center) with a 332 BSL.

    My thoery is that the release threshold can be slightly raised and the opening curve (rate) can be flattened by adding a polymer under the toe release. This would accomplish 2 desirable things.
    First, during a slow twisting release, the release force should not be significant enough to cause injury.
    Second, due to the energy absorbing properties of polymers (high hysteresis) the curve (rate) is flattened and should absord energy to prevent unwanted pre-release, espescially in chatter or making air turns in steep hard couloirs. (made that mistake once on some demo skis, forgot to turn up the DIN before jumping in).

    I have tested 2 silcone polymers (resistant to hardening in cold) with a durometer of approxiamately 25 which did infact yield a very flat curve (rate) and one added only 11% to the overall release force. The other (larger) yielded a 40% increase in overall release force.

    Note: This topic is intresting to me becuase I have fallen about 1,000 feet down a 50 degree couloir with demo Alpine bindings, my mistake for not checking the DIN.
    I have never had a pre-release with ST-10s or FT-12s (2008-2010 models) even on my Atomic RT-86s (very chatttery) which I use for bump skiing or hard surface couloirs)

    Unfortunately I will probably not be able to do field testing as I am now training for the bike racing season. Although I may be able to fit it in with one two more ski objectives this spring. I don’t like to change what already works for me.

  59. Hunter Lee April 18th, 2010 12:06 am

    Interesting discussion! I’m 6’4″ 190lbs, have Dynafit F12’s mounted on Black Diamond Verdicts(102 waiste), ski hard, and have had a couple front releases that has planted the seed of doubt in my mind regarding the binding. Both times I had my skiis off for a while in less than ideal conditions, wind and snow were blowing around the skiis.

    After the last pop out, which could have turned nasty as I had just crossed the top of a steep line doing a ski cut that ended on hard icy snow, I realised that there was some ice under the plate. From that I concluded that the build up underneath was most likely the problem as it appeared to me that the plate could not go down as it should.

    I’m no tech guy, but am looking for something more pragmatic, do others out there simply monitor the build up under the plate and keep a paranoid eye on it? I thought that I’d bring my golf divit tool out the next time I go out and play in the hills. I’ve skiied this set up hard and had no problems, but that last time freaked me out. I like to ski steep lines, and will find myself on icy hard steep slopes again, if this problem presents itself again I’ll probably change bindings, but as for now I’m just gonig to keep a real close eye underneath the plate. Anyone else out there have any proactive measures they’ve used to resolve the release issue?


  60. Jonathan Shefftz April 18th, 2010 5:56 am

    “Anyone else out there have any proactive measures they’ve used to resolve the release issue?”
    Personally I’ve never had any problems, but spraying the bindings with silicon spray beforehand can help. (I’ve done this only before rando races to save those precious extra grams and before days I knew would have sticky annoying snow.)

  61. Lou April 18th, 2010 7:56 am

    I’d add that the problem of ice building up in the space under the toe wings can contribute to a lot of supposed “pre releases.” When this occurs, the binding can appear to close on your boot and you ski away, but it may not be totally closed. Visual inspection before skiing is the main solution to this, but binding spray with silicon does help, as do some small modifications to the toe unit base plate. For example, before I mount ST10 bindings, I hollow out the base plate a bit more under the toe wings, polish that area, and rub it with alpine wax.

  62. SteveG April 18th, 2010 11:12 am

    With regards to the hollow for toe wings relief on the plastic toe base plate, I ordered a set of mud color ST plates to replace early comfort plates for an upgrade to the reinforced crampon mount. There was a significant plastic “pip” from the molding process in the bottom of the hollow. I cut it off and sanded the surface smooth. Would have been a snow catcher and tough to clear for sure. With Dynafit sales up significantly as I hear, Q.C. might be suffering a bit.

  63. Jacob S March 5th, 2011 11:44 pm

    Hey Lou,
    This is a little off topic, but this morning I had one of my G3 Onyx toe pins shear off while skinning. This obviously was the end of my weekend, a big bummer considering the presence of the light an fluffy and sun up here in BC.
    I was skinning up a logging road and thought I had stepped out of the toe piece, possibly because I forgot to lock it down, but no, the pin sheared off flush with the toe wing.
    I skied down to the trailhead and drove to Squamish and asked both backcountry shops in town if they could fix it, but they said it would be a warranty issue and I would have to contact G3 directly.
    It doesn’t seem that it would be hard to fix, just drill out the center of the remaining piece of the toe pin, and use an easy-out, then screw in a new toe pin, but both shops didn’t have a new toe pin.
    I was curious if you had heard of this issue happening with the Onyx’s before?
    I did do a routine inspection of the binding on Thursday when I swapped the bindings from the my narrower skis to my fat skis, and didn’t see any issues then.
    What are you’re thoughts on this? I guess I’m lucky that it didn’t break when I was skiing hard, better to happen on a logging road? I’ll let you know what G3 says on Monday if you’re interested.

  64. Christian November 22nd, 2011 2:30 pm

    Any hope to see a subjective prerelease test on different tech bindings?
    I can very well see that is not worth reading for people living in soft snow areas…a lot of us tend to at least ski some ice/hard snow.

    My impressions this far:
    – tlt speed (1999) on sub 78mm skis w tlt4 : no problems
    – vertical ft10 with zzero4c on 78mm ski: no problem
    – vertical ft12 with zzero4c on 85mm alpine ski, skied agressively. No problem
    – vertical ft12 with zzero4c on 105mm coomba. Problems on everything resembling ice
    – atk race with tlt5p No problem but not skied with toe open or agressively
    – vertical st with zzero4c and tlt5p on 87mm rando ski. Toe opening, but not release on jump turns on white ice, release on ice. Don’t trust the binding/ski combo on ice
    – radical ft12 (130 stoppers) with tecnica 130 flex “at” boot on 115mm ski. Didn’t leave the living room. Extremly easy prerelease. (The setup was checked by dynafit)
    – onyx on 115mm ski with tecnica 130 flex boot. Harder to prerelease in living room than radical, but prerelease on glacier ice skiing 50% of the speed done on salomon z12. This really surprised me.

    Seems like I have to make a choice between narrow skis and tech bindings, or wide skis and frame bindings.
    (I don’t actively seek ice, but frozen streams, glaciers, ridges etc often reveal patches of it. I always ski controlled. The release happens when shifting weight from one edge to the other. The reason why I would like to ski a powder ski in these contions is to stay on top all the time instead of sinking into powder, breaking crust, on top of ice etc. )

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