Torsional stiffness vs. Flex stiffness - how do you like it?

For discussions related to ski/snowboard construction/design methods and techniques.

Moderators: Head Monkey, kelvin, bigKam, skidesmond, chrismp

Post Reply
pmg
Posts: 479
Joined: Sat Dec 01, 2012 8:59 am
Location: Sonthofen

Torsional stiffness vs. Flex stiffness - how do you like it?

Post by pmg »

Hey,

am rethinking my fibrework as my skis turn out quite stiff. My Idea is to use biax Carbon for torsional stiffness and uni glass for a more relaxed flex - thats the way I like it, I want the ski to have edge grip when I want to.

However, the downside is that the ski is less forgiving in crud and other uneven terrain...

So I just want to ask around how you like your skis: Hard flex, soft torsional flex, the other way around, mid/mid, and so on. What are your thoughts regarding the balance of torsional stiffness and flex?

Cheers
Philipp
User avatar
Akiwi
Posts: 370
Joined: Thu Jan 15, 2015 7:48 am
Location: Olching (Near Munich) Germany

Post by Akiwi »

Here is my non-expert opinion.
I think that tortional stiffness is always good, so the more of that the better, particularly for on piste. It is probably not so important in soft snow .
The same goes for overall stiffness. On piste a stiffer ski will be better for powering through a turn with even pressure over the entire length of the ski, but in soft snow of course this is a huge disadvantage. In short, Tortional stiffnes is good, Fley depends on what you want to do.
I'll be interested to see what others say here.
I am nobody. Nobody's perfect, so I must be perfect.
mammuth
Posts: 449
Joined: Tue Oct 28, 2014 3:48 am
Location: somewhere in the alps

Post by mammuth »

Too much torsional stiffness and you scatter / loose your edge on hard/icy stuff.

Been there ;)
Tom
Hannes
Posts: 93
Joined: Wed Nov 09, 2011 2:20 am
Location: NRW, Germany

Post by Hannes »

After using 750 triax Glass for the last 5 Pairs I am now thinking about trying 300g Carbon biax and 400g Glass uni.
On one hand I want to save weight with the Carbon and get a torsionaly more ridgid ski. On the other I want to keep the "glassy" flex of my former layup. What do you think? Does it make sense?
The junkysupply simulator says the carbon/glass layup will be e few gramms lighter while being slightly stiffer than the pure glass layup.

Another thing that came into my mind:
To receive a certain stiffness of a ski I can
a)use a thicker core with less fibre or
b) use a thinner core with more fibre.

In case a) each fibre needs to take more stress than in case b) and vice versa. So will a ski with thinner core and more fibre keep the flexpattern for a longer time? Less stress for each fibre -- less fatigue?

I hope I didn´t mess up the technical vocabulary to much, but I am not an engineer:-)
pmg
Posts: 479
Joined: Sat Dec 01, 2012 8:59 am
Location: Sonthofen

Post by pmg »

mammuth wrote:Too much torsional stiffness and you scatter / loose your edge on hard/icy stuff.

Been there ;)
Sure it wasnt another issue? Real race skis are stiff as hell, and one thing they surely dont do is scatter on ice.

What Fibres did you use on the too stiff one? Core Thickness?
pmg
Posts: 479
Joined: Sat Dec 01, 2012 8:59 am
Location: Sonthofen

Post by pmg »

Hannes wrote:After using 750 triax Glass for the last 5 Pairs I am now thinking about trying 300g Carbon biax and 400g Glass uni.
Funny, want to do the same, but less glass, only 220g Uni glass. If you need 300g Biax Carbon write me, I got a lot of it. And it makes a lot of torsional stiffness :)

Cheers
Post Reply