lilcliffy wrote: ↑Tue Mar 15, 2022 4:42 pm
dave52 wrote: ↑Mon Mar 14, 2022 1:14 pm
My snow-cabulary is limited, what is "3D snow"?
I am using the term
"3D" snow to acknowledge that any of these BC-XC skis are going to sink into soft snow at XC speeds- therefore, one will be striding through the snow- not on top of it.
I mentioned it specifically because the Ingstad BC/WL has a significantly rockered shovel.
Tip-shovel rocker does nothing to improve striding/climbing efficiency at XC speeds-
In fact, the rocker creates glide resistance
by presenting a wider surface area that is initiating trail breaking (plus it presents a shorter glide/grip surface when climbing).
The Ingstad is a good deep snow XC ski because of its stiff, stable flex- but it is not as efficient as the non-rockered NATO ski in pure XC mode.
(The rocker certainly encourages planing and facilitates turn initiation at DOWNHILL speeds)
1. This topic (3D snow and Rocker) has already been covered in other posts;
2. When I think of “wider,” I am visualizing something different that what
@lilcliffy is describing above, so, in case it’s useful for anyone trying to understand how different skis work in deeper snow and how rocker affects that, I’ll just say the same thing a different way:
A ski with rocker (AKA “Nordic Rocker?”), like the Ingstad, or Otto Sverdrup, or others, where the front of the ski bends up fairly easily (instead of being more firm / stiff like the Amundsen), ends up creating a “ramp” that the ski wants to slide backwards on, creating resistance to forward progress. That’s why stiffer skis (to a limit) are more efficient in deeper snow. See crude drawing, below.
(In the picture, the ski is below the top surface of the snow.)
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And, just for the heck of it, a too stiff ski, like a classic / track race ski, where the camber is so stiff, it forces the tip to dive down in the snow.
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