Post
by CwmRaider » Wed Feb 01, 2023 8:47 am
My thoughts on this for having run all combos: NNN-BC, 3 pin with or without cable, and Xplore
The main control parameters are defined by (in no particular order)
1) boot ankle support, lateral and torsional rigidity, to some extent dictated by the sole structure. This in turn is related to binding norms; Rottefella supplies NNN-BC or Xplore soles, and some of the 75mm boot soles seem standardized, although they are of different duckbill thickness.
2) Resistance to heel lift, to be able to pressure the front of the ski. This comes from a stiff sole and either a hard flexor or a cable on the binding
3) Technique
The cable on the 3 pin cable system has a front attachment point well behind the pin line. What this does is,
1) Increase overall resistance to heel lift
2) Increase the pressure on the ski forwards of the binding while reducing pressure behind the binding
3) Compress the boot forwards into the binding, helping the boot to flex at given flex points
On NNN-BC and Xplore, increasing the flexor stiffness:
1) Increases overall resistance to heel lift
2) Increases the pressure on the ski forwards of the binding while reducing pressure behind the binding
Boot flexing with NNN-BC and Xplore is dependent on technique and how the skier pressures down on the the boot. It is made easier with stiffer flexors as opposed to cables. The difference in how cables operate relative to flexors, is that the cables use part of their tension to crunch the boot and aid in boot flexing, whereas with stiffer flexors, all of the increased resistance to heel lift is translated into more pressure in front of the binding and less behind the binding.
I find that the hard flexor offers similar heel lift resistance to cables, in the way I set them up. But this would depend on how stiff one sets the cables. This means that in theory one should be able to pressure the front of the ski more with flexors, if one can find the right technique / strength to transfer the force to the ski.
Torsional rigidity: My impressions so far are that Xplore soles have better torsional rigidity than all NNN-BC boots, thus aiding with edge control. It is also better than a vast majority of presently available leather 75mm sole systems. I need time on hard snow to compare the torsional rigidity of the Alfa Free Xplore VS Fischer Transnordic 75mm. Plastic boots like the T4 etc have better torsional rigidity, obviously.
Boot ankle support: The most supportive boot options are Alfa Free (Xplore), Fischer Transnordic (BC and 75mm), and plastic boots for 75mm. The Alfa Free is comparable to the Transnordic BC/75, and, according to some, comparable to the plastic T4 in practice. This is not binding dependent, but boot options come and go on different binding systems. New options in the 75mm market are wearing thin.
From a binding perspective, the Xplore has better ergonomics with a step-in function, and can be transformed into either a free pivot binding, or a binding offering moderate to high heel lift resistance, for a very light overall weight. Engaging the free pivot mode requires to remove the ski and change the plate. So it is more difficult than the Voile Switchback. But the latter has a weight of 1362 g/ pair. The Xplore is only 378g/pair.
Engaging the increased heel lift resistance similarly requires a different flexor. The Voile 3 pin cable is 810g/pair (or 998 g for the traverse model with the option to clip the cable behind the binding). The Voile Hardwire 3 pin is 1290 g/pair, and the Super Telemark with Cable is 962 g/pair (no cable clip behind the binding option).
The bottom line is, that the Xplore offers a lot of functionality for the low weight. Changing flexors is slightly cumbersome but less so than adding or removing cables, and certainly easier than changing the flexors on NNN-BC.
If we admit that the support and torsional rigidity of the Alfa Free is comparable to the Fischer Transnordic 75 or BC, I am willing to say that the performance of the boot + binding combination is certainly better than NNN-BC or basic 3 pin 75mm. How it compares to the 3 pin cable with an equivalent boot - for now I am unsure. That said that the difference is not hugely obvious is telling. Intuitively, the cable may offer some more support due to the assistance provided in keeping the ball of foot flat on the binding.
For me the telemark turn is a means to an end. I am also happy skiing P turns with Fjellski. Whichever technique is suitable or feels right at a given time is the one I will use.
It is clear to me that the performance offered by a Scarpa T4 with cable binding is out of reach for the Xplore binding at the moment, but the T4 just did not work for my feet.
The above is most relevant from an xcd perspective. If you're only interested in touring flat ish terrain, NNN-BC or 75mm will offer similar performance in my opinion.
Last edited by
CwmRaider on Wed Feb 01, 2023 10:27 am, edited 1 time in total.