Tech Binding Pre Release Dec 6,2017

I just don't think the Dynafits respond well to a hard, icy surface under foot.  There's nothing in the toe to provide cushion or absorb the shock that an icy surface can transfer through the ski. 

Yup. Elastic travel! One of the main selling points (deservedly) for high-end alpine clamps. The feel of pintech is absolute dogshit on firm/mixed compared to a proper downhill binder. Pins inbounds sorta work till you push em.

I've had frighteningly similar pre-release issues, and I don't think it had anything to do with bits of ice or ski flex.  Granted, my sample size is small as I only expanded my touring quiver beyond the Barons mid season last year, but on two inbounds days (one at Whiteface and one at Baker) I had very unexpected pre-releases. 

I've skied the Dynafit setup hard in both the Tahoe and Baker backcountry, as well as skied The Fingers and Ah Chute at Squaw on them, and in good (soft/powder) snow conditions they've performed like a trooper.  Heck, if you want to see what kind of ski flex the Dynafits can really handle take a look at my survival skiing video of a steep and narrow chute that I navigated off the Elbow at Baker.  (Don't judge me, please! :-[ Like I said....I navigated, not skied, that one in survival mode.  I'm a near 50 year old east coast skier, so please forgive my lack of stomp-age.  )

vimeo.com/210708421

I just don't think the Dynafits respond well to a hard, icy surface under foot.  There's nothing in the toe to provide cushion or absorb the shock that an icy surface can transfer through the ski.  I love the Dynafit setup but it has its limitations, and isn't a great choice for less than ideal inbounds conditions.  Not surprising, because that's not what it was made for!

My Whiteface pre-release was similar to yours.  Skiing powder on Skyward I hit a transition to a hard, wind blown, icy stretch at speed.  No hard turn, no bumps, just a smooth transition onto ice.  All of a sudden a feeling something isn't right, then I watch my right ski head off on its own.  The high speed yard sale  that followed could have been a lot worse, thankfully.  Cranked the bindings and added a pair of Dynafit leashes after that experience....

Loved your terrain selection! No matter how old we get there is still an idiot inside who comes out every so often. Obviously they did deal with flex😜

Elasticity is the winning answer. Makes perfect sense. I have seen my toe piece on an alpine binding go so far to the side it actually stayed there for a second and gave me time to pop back in, instead of taking a nasty early morning springtime fall on Gunbarrels's huge hard bumps.

Which all comes nicely back to my original comment -'stay safe out there. There are a great
Many ways these bindings can underperform an alpine setup.

Thanks all, I seem to have just a minor strain. Now the left knee hurts like the right one...Might balance me out better.😉⛷

Certainly icing in the pin pockets can be a problem; I suspect most of tech binding users have experienced such a pre-release--even after two strides of clicking in. That's why Dynafit pins have a cutting edge and one is wise to rotate those pins a bit when first stepping in; I also use a lilttle silicon lube on the fittings to prevent icing but YMMV. Elasticity is a major issue in skiing fast as well.

But remember flexing that influences heel pin retention only occurs on the rebound (bowed with tips and tails lower than the heel) not on the decambering (or with tips and tails higher than the foot as that compresses the heel of the binding against the heel of the boot); rebound is magnified at high speeds and on hard surfaces. Of course "minding the gap" setting the gap between heel of boot and binding heel piece is a major requirement of effective use of tech bindings without spring-loaded mobile heels.

I have found that the safest best place for pin bindings is in the garbage . X

Had my first "surprise" release a couple weeks ago on Ion 10's. Smooth surface, hard underneath and a few inches of cut-up fluff over it. On the un-weighted segment of the turn where the ski (corrected: rebounds ), felt a big grab which was a brake. That occurs as I'm weighting the next turn. Ski is departing and I'm pulled around and barrel downhill over the remaining ski. Could not see any rocks around, ski bases no different, what was that all about? The Ion's heel has movement and the front pins claim to have excellent retention. Maybe shock and vibration can affect Tech-type binders? Really doubtful there was any snow/ ice problems and they navigated 2,300 feet of variable before doing the deed. Hhmmm?