[See our binding toe closure strength testing]
This was kept on the downlow insofar as even after traveling to Europe last winter as a journalist, I’m embarrassed to say WildSnow didn’t somehow get the info sooner. Of course, if we had gleaned the inside story we’d probably have been sworn to non-disclosure. Whatever. Here is the story.
Normal ST/FT Dynafit spring in left binding, firmer FTZ12/110 spring is in right hand binding. Difference is obvious. Firmer spring is darker, and has more space between coils. It's about 20 percent firmer. Click image to enlarge.
Ostensibly due to a small percentage (but nonetheless important group) of backcountry skiers who have trouble staying in Dynafit bindings even after making sure everything is being done correctly (in terms of ice removal and such), Dynafit is now selling their 110 mm brake FTZ12 model with stronger springs in the toe. The net effect of this is that the toe will have more holding power in situations where the boot exerts sideways pressure and/or vibration that could open the toe wings and cause inadvertent release (“pre-release”). At this point the springs only come on the binding sold with the 110mm brake, which is said to be so because skiers with wider skis are more likely to have the retention problem. My crystal ball tells me there is no reason these springs won’t eventually be available on all Dynafit binding toes as they appear to work fine, and because of binding mechanics don’t appear to change the release values in any noticeable way.
We have an FTZ12 binding with the new springs, and our crude but nonetheless repeatable testing indicates that the new springs are around 20% firmer than the old ones.
Below is a video of the type of force and motion I believe could cause occasional pre-release for a very small subset of skiers out there. I debated sharing this, as some of you will probably needlessly obsess on it. But since Dynafit opened the can first by making what’s essentially a new binding model with the stronger spring, I’m duty bound to analyze what’s perhaps behind that.
WildSnow.com publisher emeritus and founder Lou (Louis Dawson) has a 50+ years career in climbing, backcountry skiing and ski mountaineering. He was the first person in history to ski down all 54 Colorado 14,000-foot peaks, has authored numerous books about about backcountry skiing, and has skied from the summit of Denali in Alaska, North America’s highest mountain.
