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Binding non release tech soles in frame bindings

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 kevin stephens 26 Dec 2016

Some interesting if not scary thoughts in this video.
youtube.com/watch?v=XZ7Y5EzCiEg&
around 25 minutes long but well worth watching. I've never had any problems with Scarpa Denalis in Diamir Eagle bindings; anybody else?
Post edited at 23:12
 Dave 27 Dec 2016
In reply to kevin stephens:

No. And given twenty years or so worth of data in probably hundreds of thousands of users using touring boots in Fritschi fame bindings in particular without, as far as I'm aware, reports of excessive injury rates in those bindings, I do wonder whether this is a case of lab testing not adequately reflecting real world use. Good point about unlocking the toe in pin bindings if you are skinning a risky slope. Though perhaps better to ask why you are there in the first place.
 DaveHK 27 Dec 2016
In reply to Dave:
> Good point about unlocking the toe in pin bindings if you are skinning a risky slope. Though perhaps better to ask why you are there in the first place.

I find my skis fall off a lot if I do that.

I agree that there's something not quite adding up between the research and my perception/experience of frame bindings.
Post edited at 08:42
 damowilk 27 Dec 2016
In reply to DaveHK:

Not to pick on you in particular, but personal experience/anecdote is poor at appreciating low frequency but severe consequential events (at least the ones that can be mitigated in some way.)

I think the main point I took away was one of his last, that many skiers may be taking risks they're not aware of: I was happily skiing touring boots in frame bindings for a while, blithely unaware there could be an issue.
I now ski tech bindings, and have gradually become aware that the release and the binding setting probably only have an approximate relationship! It doesn't mean I've stopped touring, but I prefer to know the limitations, and hopefully interpretation of data like this leads to better equipment and also understanding of how to use it.
 DaveHK 27 Dec 2016
In reply to damowilk:
> Not to pick on you in particular, but personal experience/anecdote is poor at appreciating low frequency but severe consequential events (at least the ones that can be mitigated in some way.)

I realise that the issue here could be with my perception. However, as others pointed out, if it's the massive issue the presenter suggests then surely it should translate into higher frequency events in the real world? I wonder if there are stats on injury rates with frame bindings? I've certainly never seen anything to suggest there is an issue but I'm not widely read on it.
Post edited at 10:17
 damowilk 27 Dec 2016
In reply to DaveHK:

I doubt overall numbers are high: 17% of all avalanche victims with a lower limb injury from the European data he used, but hard to know how many of those would be due to lack of ski release. Then probably larger numbers of non-avalanche lower limb injuries, again attribution of cause will be difficult, but any spiral lower leg fracture is possibly from a release problem.

If you can reduce a risk, or at least identify it, that's worth doing, as long as you don't just shift it to a different type of risk or injury: there was an interesting discussion on Wildsnow about the different pivot point of various bindings predisposing to different injury profiles: either predominantly knee or spiral lower leg fractures.
The bit I found interesting was that toe pivoting tech bindings like the Vipecs that have been thought to be better for release, may actually be riskier for knee injuries, but better for spiral fractures, than conventional tech bindings that are the opposite.
In reply to kevin stephens:

I found the film interesting, but I've never experienced problems with soles sticking to the sole plate hindering binding release. I've always been careful to set the sole plate with a paper thin gap beneath the sole (I've found some ski techs are not so careful). In many falls eg catching an edge, and in an avalanche the ski would be un-weighted or certainly not as weighted as in the compression part of a turn. I wonder how much compression/weighting of the ski was used in the test rig shown in the film?
 Martin W 30 Dec 2016
In reply to kevin stephens:

The other question I have in my mind about the test rig was whether the results obtained by slowly increasing the twisting force would correspond well to those experienced in a sudden twisting fall? I'm not saying that the results from the test rig are invalid but I think it would be useful to understand how they compare to forces arising from sudden loadings.

I'd suggest that very few skiing falls involve a gradual increase in forces over several seconds, which is what the videos of the test rig seem to show (though they might have been filmed in slow-mo). I'm pretty sure that I have had a (very) few falls in the past which did happen quite slowly, ending up with me sliding down the hill with my leg uncomfortably twisted under/behind me (though not sufficient to cause long-lasting injury) without the binding releasing. Every high-speed fall I've had, the skis have pinged off before I was even aware of any strain on the leg/knee.
 Jim 1003 17 Jan 2017
In reply to Martin W:

I notice with my Hagan bindings and my Fritschi free ride the boot does not really touch the binding apart from at the toe and heel, so can't see what difference the sole type would make At the toe piece the boot is also not touching as you should be able to slide a thin card under it if it is adjusted correctly.
I only use touring boots and bindings and ski all winter, as do most people who work on the lifts. I've got to say bollocks to the gents research, but good of the OP to raise it.
1
MarkJH 17 Jan 2017
In reply to Jim 1003:

> .....the boot does not really touch the binding apart from at the toe and heel, so can't see what difference the sole type would make At the toe piece the boot is also not touching as you should be able to slide a thin card under it if it is adjusted correctly

That gap is for binding adjustment with a static ski and unweighted boot. It doesn't mean that your boot sole will not touch the release plate when you are skiing/ falling.
 Jim 1003 17 Jan 2017
In reply to MarkJH:
Cheers, but presumably it's at that height for a reason? Does it mean it's just touching, or how do you know it's toughing at all, when weighted.?
Post edited at 16:26
MarkJH 17 Jan 2017
In reply to Jim 1003:

> Cheers, but presumably it's at that height for a reason? Does it mean it's just touching, or how do you know it's toughing at all?

The height is set to allow a small gap such that there is no mechanical compression of the boot into the ski by the height adjuster whilst also minimising the freeplay of the boot in the binding. Your boot will still move in the binding (and relative to the ski) when you are skiing. The release plate is to ensure that if your boots are touching the ski as you fall, then friction is not working to prevent release.
 Jim 1003 17 Jan 2017
In reply to MarkJH:

Yes, that's what I thought, so I don't understand the research seeming to show a release issue, as there can only be a minimum amount of friction whichever type of boot is in a touring binding.
1
MarkJH 17 Jan 2017
In reply to Jim 1003:

> Yes, that's what I thought, so I don't understand the research seeming to show a release issue, as there can only be a minimum amount of friction whichever type of boot is in a touring binding.

It didn't seem that clear to me either, but at 11.25 in the video, he seems to suggest that the projection of the inserts in 'tech' boots interferes with lateral release in frame bindings. My impression was that he was saying that although everyone knows about not using touring boots in alpine bindings, we should also avoid using boots with inserts in frame bindings.

As it happens, that is exactly the setup I use at the moment and I can't say I've noticed any problems with release, but good to be aware of potential problems all the same. It would be interesting to see if there are any injury stats that back up his lab results.
 Jim 1003 17 Jan 2017
In reply to MarkJH:

I didn't pick up on the fact it was just an inserts issue so ta for pointing that out.

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