Dynafit toe pre-releasing

I've had the same symptoms in hard snow conditions, at least once in a place where losing the ski would've been real bad.  Usually happened when stomping hard for purchase when sideslipping, making stem christies, or just trying to get a better grip on the mountain.

This led me to start partially locking the toepiece. A broken ankle later convinced me to reverse that plan, except in cases where a pre-release might get me hurt. Still haven't felt the need to lock them since.

Since 2009, I've had only one (double) pre-release on firm snow. The experience was very similar to Pete's. 105 mm skis and Comforts on rain-glazed knife-hard snow. I pivoted out on the heels, so I was clearly applying torque through my feet at the time. It was a real surprise.

I'm bummed to hear that you've had the experience with a pair of Radicals. The Power Towers in the toepiece should, in principle, address the problem pretty well. I believe the problem is mostly a lack of elasticity in the toepiece release function, and relates to forces, not torques, generated from a good sideways stomp.

How big are your boots?


If you resort to locking the toe, know that release characteristics can vary considerably from binding to binding (and perhaps mount-to-mount). In my 06/07 Comforts and 07/08 Speeds, lateral release can happen on a partially-locked binding.  My 08/09 Speeds at "two clicks" are stronger than my fibula.

Every time I have had this happen to me or seen it happen to someone else (including the la sportiva tech bindings) it has been due to ice under the spring area causing the pins to not poke inwards enough.

Every time I have had this happen to me or seen it happen to someone else (including the la sportiva tech bindings) it has been due to ice under the spring area causing the pins to not poke inwards enough.

If I even think there is snow or ice under the spring area , I recycle the toe piece by hand two or three times. Two prs of ST and one old TLT speed. No problems even with the widest setup at a clumsy 195 #.

...creates a similar (or exact) force like Lou’s video (

).

I've have had that exact malfunction. For me turned out to be a fairly easy fix.

If you watch Lou's viddy closely you'll see the toe of the boot move down (towards the ski) as the force is applied to it. Since the pins and the boot dimples are conical they serve as an incline plane to impart a spreading (opening) force on the pin cross arms.

I first noticed this happening with a pair of boots that had a lot of hiking/climbing on the wear on the sole toes.
I could actually see the pins creep up and out of the boot dimples under hard edging. I first thought of trying to get heaver springs for the cross arms but didn't like the idea of potential messing the release machinery.

I ended up building up the boot sole toes with freesole so that they just lightly rested on the center pin cross arms operating bar (the metal bar that connects from the cross bar to the plastic operating lever) when the pins are engaged on the boot. Once built up, the boot sole toe pressure on the operating bar helped maintain "close" pressure on the pins. And with those three points of contact (the boot sole and the two pins) the movement of the boot in the pins during hard edging was no more.

Now I always make sure new boots rest firmly on the pin cross arms operating when locked in. I also check from time to time to make sure that no gap exists there.

I believe that if the boot sole toe contacts the binding properly when locked in, the only other conditions that might cause a pre-release is ice in the boot dimples, or the condition that bwalt822 mentioned, snow/ice build-up under the cross bar/spring area. If one snaps the toepiece mechanism a few times (open/closed), as Robie suggests, before hooking in that usually dislodges the snow/ice under the cross bar… especially if you occasionally spray or drizzle most anything slippery in that depression under the cross bar.

Others have mentioned good solutions for ice in the boot dimples.

Snow and ice in, under and around the toe and dimples is pretty straight forward and definitely not a factor in these incidents. Charlie described it perfectly "happened when stomping hard for purchase". That is exactly when its happening. Skis perpendicular to the fall line on hard snow stomping the down hill ski for purchase. Not viciously stomping but firm enough to attempt a purchase on rock hard snow. The boot soul is something to consider but after trolling some of the other forums and finding other instances it is definitely a glitch.

Thats a bold statement to say all dynafit bindings are defective. I've skied nearly 150 days over the last three years on my vertical sts and tlt speeds, on skis of 102 mm, 99mm, 115 mm and 138 mm underfoot in all kinds of snow conditions. Never had toe pre-releases, I also never take my skis off at the top of a run when possible.