This is my first post. I am interested in ski design, but I admit I haven't gotten serious yet about building/construction details. This is a sweet community you have here, and I applaud all of you and your efforts.
My question:
What do you think is the best short-hand way to communicate or specify "tip rocker", so you can tell which ski has "more rocker" than another ski?
Maybe I am misusing the term "rocker". Basically I just want to know the best short-hand numeric representation of the curve(s) of the front portion of the ski that is up off of the snow.
Sure, the most comprehensive way is to visually compare the actual side view curves in graphs or photos, but I'd like to know if you have figured out a short-hand way to do it with just a few numbers, allowing quick comparison between ski designs. Maybe rise over run? Or radius and angle? Or something else?
For example, K2 used to specify Hellbent tip rocker like "20/40", meaning 20mm rise over a 40cm length from base contact point to some other vaguely-defined point which is NOT the very end of the tip. I still don't know how K2 defined that point. If you ski builders use a similar method to communicate and compare, how exactly do you define the 2nd point (hopefully via a method that is measurable and repeatable)?
Thanks in advance.
-Vitamin I
What is best short-hand way to specify amount of tip rocker?
Moderators: Head Monkey, kelvin, bigKam, skidesmond, chrismp
endre (moderator here) replied to me via email, about his experiences measuring skis for FriFlyt magazine (a.k.a "FF" below). He wrote:
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Making a universal, geometrically simple definition of rockers seems to be
very difficult. The first year when I started to define rockers in FF there
seemed to be a trend where the manufacturers used 2 different curves of
visually different radiuses (so that it was easy to mark the point between).
For that reason we printed length and height of both those shapes (rocker
and tip bend).
Nowadays though (and the skis I make myself included) many skis seem to have
a more complex linking if curves through the whole ski profile. Therefore I
found It useless to continue the same definition as the first year. Now we
print length and height of the whole rocker and tip (combined) + height of
the whole ski tip and rocker (combined) like this: 350x64mm or a mor trad.
ski could be: 180x72mm.
This definition only reflects the size of the rocker, and not the shape. The
shape should additionally be described in verbal terms such as "flat start
to traditional tip" or "one single tip radius" or "gradually rizing tip" or
whatever. For more technical descriptions radiuses can be added, (this is
what we do for production.)
------------
So, based on endre's input, it sounds like there really is no useful way to specify rocker with only a few standard measurements---and the best way to describe what is happening between the 2 key points is to include some words or a curve with the numbers.
-----------
Making a universal, geometrically simple definition of rockers seems to be
very difficult. The first year when I started to define rockers in FF there
seemed to be a trend where the manufacturers used 2 different curves of
visually different radiuses (so that it was easy to mark the point between).
For that reason we printed length and height of both those shapes (rocker
and tip bend).
Nowadays though (and the skis I make myself included) many skis seem to have
a more complex linking if curves through the whole ski profile. Therefore I
found It useless to continue the same definition as the first year. Now we
print length and height of the whole rocker and tip (combined) + height of
the whole ski tip and rocker (combined) like this: 350x64mm or a mor trad.
ski could be: 180x72mm.
This definition only reflects the size of the rocker, and not the shape. The
shape should additionally be described in verbal terms such as "flat start
to traditional tip" or "one single tip radius" or "gradually rizing tip" or
whatever. For more technical descriptions radiuses can be added, (this is
what we do for production.)
------------
So, based on endre's input, it sounds like there really is no useful way to specify rocker with only a few standard measurements---and the best way to describe what is happening between the 2 key points is to include some words or a curve with the numbers.
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doughboyshredder
- Posts: 1354
- Joined: Mon Sep 17, 2007 7:37 pm
I kind of disagree. IMO rocker is any portion of the ski before the end of the effective edge that is lifted. The shovel is the portion of the ski that is lifted past the end of the effective edge.vitamin i wrote:
So, based on endre's input, it sounds like there really is no useful way to specify rocker with only a few standard measurements---and the best way to describe what is happening between the 2 key points is to include some words or a curve with the numbers.
Of course this doesn't necessarily apply to skis with "tapered" tips. Although that's really just semantics.
In describing how much rocker is being built in to a pair of skis or a board a lot of us on here use rise over length. For example 2cm rocker over 20 cm.
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MontuckyMadman
- Posts: 2395
- Joined: Fri Jun 20, 2008 9:41 pm
Ok, I am just now re-learning the precise definitons af "rocker", "shovel", etc. And I agree with your definitions.doughboyshredder wrote: ...IMO rocker is any portion of the ski before the end of the effective edge that is lifted. The shovel is the portion of the ski that is lifted past the end of the effective edge.
Of course this doesn't necessarily apply to skis with "tapered" tips. Although that's really just semantics...
Rethinking my question, I guess what I want to specify is not precisely "rocker" at all, but the side profile of the whole tip portion that is off the snow, independent of the properties of the top view (e.g. independent of the end of the effective edge/sidecut, etc.). So in the end, it turns out I am just trying to specify a section of a function by reporting only 2 endpoints and some minimal extra information about that function, but I want that minimal information to be enough to allow useful comparison of the curves for the purposes of ski design.
Put that way, my quest sounds dumb. I guess I need to think more about this.
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doughboyshredder
- Posts: 1354
- Joined: Mon Sep 17, 2007 7:37 pm
uhhh, hot as dded.MontuckyMadman wrote:if you do 2cm over 20cm them how do you specify the rise point for the shovel.
and how do you describe this shit?
Like, she can come live with me in the woods anytime hot.
oh, you meant the skis? Sorry. Got distracted by the hotness.
Yeah, I wasn't thinking about reverse sidecut skis. That makes it even more difficult.
This started to happen a while ago It's censorship at its automated finest.webboy wrote:Please, what does "dded" mean for the FOGs? I googled and failed...doughboyshredder wrote:uhhh, hot as dded.
type the F-word or a few others and it comes out dded.
sam
You don't even have a legit signature, nothing to reveal who you are and what you do...
Best of luck to you. (uneva)
Best of luck to you. (uneva)
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skidesmond
- Posts: 2337
- Joined: Tue Apr 07, 2009 3:26 pm
- Location: Western Mass, USA
- Contact:
That's funny, I googled it awhile ago also but found nothing. I figured it meant something like that just by the context I saw it used in. Even FOG's can learn something new every day.webboy wrote:Please, what does "dded" mean for the FOGs? I googled and failed...doughboyshredder wrote:uhhh, hot as dded.