You know those pedestrian switches at stoplights? The ones that supposedly let the light computer know you’re waiting to cross and will bias the lights for you if you give it a slap? My family has always laughed at my theory that some of these do nothing, and are just there to appease the impatient who would otherwise walk against the light. Yeah, I’m crazy. But hey, are you sure every one of those is actually wired to the system and does something? SURE?
Likewise, I’m a skeptic when binding companies come up with “stiffeners” or “vibration dampers” working off a plate under the foot. First, some such systems can be shown to do virtually nothing except look good in the ski shop (no names will be mentioned), while others that show an effect on the test bench many still have little or no effect on the actual performance of your skis and bindings. Why? As one engineer I spoke with put it, “for that plate to do much if anything, it would have to have a significant amount of strength or damping in relation to the flex properties of the ski, otherwise it’s just too small a percentage to have any real effect on performance.”
Perhaps most importantly, on the lightweight Dynafit Radical FT ski touring binding this added mechanical system is piling on a significant 48 grams (1.7 ounces) per binding. Is it worth it?
We’ll report, but ultimately you’ll have to decide.
Specifically, what about Dynafit’s Radical FT 12 “special plate that can be used for changing the stiffness of the system,” as this component is termed in the consumer info enclosed with the binding? First, know that most ski bindings have provision for the ski flexing under the foot (to avoid the dreaded “stiff spot”), but such provision usually has some form of inherent of vibration dampening either due to friction, or a spring and friction system. Tech bindings allow for flex, but have virtually no vibration damping. In other words, when the ski flexes, it moves the tech binding rear pins in and out of the boot heel fitting with no damping action or friction. That’s good when you want your ski to bend freely and indeed has been a well liked feature for years, but when you want some attenuation for things like ski chatter, you’re getting none.
What’s more, if the ski flexes hard, it can drive your boot heel against the tech binding heel fitting housing (see photo above) — possibly causing unintended release or even binding damage. The harder a ski is skied and the larger the skier, the more likely this is (and also the reason the tech binding ‘heel gap’ is such an important setting, not to mention the length of the pins). Hence, I’d agree with Dynafit that developing some form of damping or stiffening under the boot, between the binding toe and heel, is a good idea for aggressive skiing (so long as you can switch the system on and off, and it doesn’t add too much mass.)
Well, our dose of Dynafit coolaid had worn off some time ago (despite the constant accusations of bias we receive), so instead of assuming the FT-12 vibration damper worked, we did some bench tests to actually show what it does. First, terminology: Calling this a stiffness changer rather than a damper is I suppose fair, but a bit misleading as the system works not by rigidly connecting the toe and heel units, but rather by providing cushioning from small flexible dampers on the underside of the heel unit that slightly engage when the ski is bent into a turn. While this does make the binding and ski in one sense “stiffer” under the foot, a more accurate take is that it cushions the ski flex in that area, and is thus a vibration damper. More, during our testing we found that unless we added an unusual amount of flex to our simulated plexiglass ski, the system most definitely added nothing more than a very small amount of cushioning. So we’ll definitely call it a vibration damper, not a stiffener.
Conclusion: As you can see from our images and testing, the mechanics of this system actually do have a mechanical effect that could be beneficial when the ski is curved (bent) as if in a turn. More, we also experimented with “over-cambering” the simulated ski, in the direction that sometimes pulls the pins out of the boot fitting in unusual situations or while super aggressive skiing. In over-cambering, the damper/sitffener has absolutely zero effect as far as we could tell.
How much of this damping or stiffening effect you’ll experience in real life is an open question. Indeed, as at least one skier has related to me, you can ski the binding with the system on or off and feel the difference. If so, terrific. If, on the other hand, you see no need for this extra plastic the binding can be easily mounted without, at a savings of 48 grams (1.7 ounces) per binding. Let us know your take!
(Note to home mounters: When doing a paper template mount, simply adjust distance between Radical FT 12 toe and heel unit so the damper system can be set to the “off” position and the connector plate mates with the obvious slots in the underside of the heel unit. Which slots you’ll usually mate the plate with is indicted by BSL numbers on top of the heel unit. If you choose to forgo mounting with the plate system, bed the toe unit in a nice puddle of epoxy just for good measure.)