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Re: torsional stiffness vs longitudinal stiffness
Posted: Wed Aug 11, 2021 1:04 pm
by riel
Woodserson wrote: ↑Tue Aug 10, 2021 12:22 pm
More torsional rigidity is possible, usually with more weight. Think of downhill skis right? but Christ they are heavy.
The question is getting the TR without the extra weight, especially in XCD pursuits where we are not powered solely by gravity.
I'm guessing the ski manufacturers have poured very little money and brain power into this, especially for this niche as they are all of 38 people who really think about this on the planet and half of them are on this site.
There's more to it than that.
A lot of the skis used for human-powered skiing are either narrower cross country skis, or longitudinally softer flexing alpine touring skis. Neither of those needs a ton of torsional rigidity, because with little sidecut or soft flex, the entire edge of the ski will be touching the snow almost regardless of what you do.
It is really only the XCD skis with >= 20mm sidecut and stiff flex that need it, which means Fischer Traverse 78 through S-Bound 112, Asnes Nansen through Ingstad, Rossignol BC80 through 120, Alpina Discovery 80 & 102, and a few more skis like that.
You are talking about a fairly small subset of the lineup of each manufacturer where this really matters, and then it still might not matter when the snow is fairly soft! We're talking a small subset of each manufacturer's lineup, during certain snow conditions.
Re: torsional stiffness vs longitudinal stiffness
Posted: Wed Aug 11, 2021 6:47 pm
by lowangle al
I wouldn't let how a ski performs sidestepping up a trail affect my opinion of the ski. It is such a small part of what we do on skis. It's also possible that the trail had a belly in it compounding the problem. If I couldn't get the center of my ski to touch the snow I would either take them off and walk up, or turn around, if it was more than a couple minutes of climbing. It happens with wide alpine type skis also.
Re: torsional stiffness vs longitudinal stiffness
Posted: Thu Aug 12, 2021 7:54 pm
by Woodserson
riel wrote: ↑Wed Aug 11, 2021 1:04 pm
Woodserson wrote: ↑Tue Aug 10, 2021 12:22 pm
More torsional rigidity is possible, usually with more weight. Think of downhill skis right? but Christ they are heavy.
The question is getting the TR without the extra weight, especially in XCD pursuits where we are not powered solely by gravity.
I'm guessing the ski manufacturers have poured very little money and brain power into this, especially for this niche as they are all of 38 people who really think about this on the planet and half of them are on this site.
There's more to it than that.
A lot of the skis used for human-powered skiing are either narrower cross country skis, or longitudinally softer flexing alpine touring skis. Neither of those needs a ton of torsional rigidity, because with little sidecut or soft flex, the entire edge of the ski will be touching the snow almost regardless of what you do.
It is really only the XCD skis with >= 20mm sidecut and stiff flex that need it, which means Fischer Traverse 78 through S-Bound 112, Asnes Nansen through Ingstad, Rossignol BC80 through 120, Alpina Discovery 80 & 102, and a few more skis like that.
You are talking about a fairly small subset of the lineup of each manufacturer where this really matters, and then it still might not matter when the snow is fairly soft! We're talking a small subset of each manufacturer's lineup, during certain snow conditions.
We are going to have to talk about this in person. In the Corner of Excellence.
Re: torsional stiffness vs longitudinal stiffness
Posted: Sun Aug 15, 2021 6:32 pm
by trashcat
These replies have been super helpful. I've personally been working on Hok style skis where it seems like it might not help all that much, but I could see myself branching out into other kinds of skis if I thought I could do something innovative or at least interesting.
I want to ask this question, then, based on feedback: if I could make an Ingstad with the patent I posted at the beginning of this thread that didn't add any (or minimal) weight to the ski, would it be an improvement?
...I think the answer is yes, but I just want to hear what more informed people have to say.