Originally Posted by TomB
HS: It is less torsionally stiff than a mantra...however, it's mounted with 11-17 din salomons which are massively laterally stiff.
I don't get this statement. My understanding is that torsional stiffnes is about tail and tip construction, not what is under the boot. DIN has nothing to do with how stiff a binding is, unless one takes into account elasticity of the release mechanism - which should NOT come into play during high speed carves.
Correct - torsional stiffness keeps the tip and tail edges at an angle close to the underfoot edge, and allows it to grip on ice. Most modern skis are torsionally stiff enough to carve on ice if tuned properly. Really.
Anyway, on the bindings. If you have a flexy binding, your lateral inputs are not going to be directly translated to the ski. Say, you angle you leg/boot over 45 degrees, but your ski only tips 35 degrees because of the slop and flex in the binding. Soft snow is okay because you aren't generating heavy lateral forces on the binding because there is snow pressure under most of the ski. But when you edge on ice, all the load is on the side of the ski, at the edge - on a fat ski, this can create major loads, leading to major flex and chattering, or lack of carving.
Finally, yes, typically higher din binding are stiffer as a general rule. MUCH, MUCH stiffer. This is for three reasons.
First is that they are mostly composed of aluminum for their main housings - much stiffer than plastic.
Second is that they usually have design changes to make them stiffer, and also change how the elastic travel works/feels - for example, a S916 heel releases MUCH differently than a 14 din 997 even though they are only different by two din points and are essentially the same heel. The 916 has elastic travel, but it only comes after major force. I actually have around 300 days on various green spring salomons, and I've only released from the heels once....and it hurt my ankle. Same deal with the true look turntable - when you are carving, and bend the ski, it loads up the heel with rearward force which creates more downward pressure on the heel in the binding, increasing the stiffness - so, the harder you carve, the stiffer laterally they get. If you hit something while going straight and pull up, however, the heel can move up in the turntable quite a bit before actually realasing.
Finally, actually running higher dins (and corresponding forward pressure)does mean that there is more force required for elastic travel and flex, meaning the whole interface is stiffer. Since both salomon and look race toes do have upward movement at the toe, higher din helps.
At this point, I almost exclusively ski salomon 916-type bindings and look turntables with the Geze (rossi toe). These are the bindings I've actually skied on this season thus far...
Salomon 997 11-17 din
Salomon 957 composites
Rossignol 180 pro
Rossignol 180 Freeride
Plus I have about 10 other pairs of race bindings....so I may have tried a few things and know what I'm talking about.....