about convex skis: this is just sooooo oldschool!
friend of mine skied planks with convex base for ski-ballet or oldschool-freestyle "on the ground" or however you want to call it. a good 20-30 years ago. i think he once told me that olin manufactured some back in the days...
very very turny and slideable on flat ground. exceptional for rotations with the skis on the ground, they spinned like hell and the spins could be indicated very easily by giving some impulses wit the edges in tip and tail...
but i personally wouldn`t ski such a ski nowadays. for the oldschool freestyle stuff it may have worked perfectly, but on slopes.... not enough control. maybe for the park-kiddies.
rockered skis
Moderators: Head Monkey, kelvin, bigKam, skidesmond, chrismp
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Wannabebuilder
- Posts: 60
- Joined: Sat Oct 20, 2007 8:22 am
libtech
y'all seen these things?
http://www.libtechnas.com/
Not as radical as you may think the wiggles are pretty minor.
They only go the area slightly more than under foot.
NAS are the skis.
What about forgetting normal sidecut and using and inverse side cut rockered pow stick with camber and this crazy wavy edge.
Increasing the contact points with a smaller effective edge would give considerable more control on the hard.
I saw some the other day at BB. I will be investigating further.
http://www.libtechnas.com/
Not as radical as you may think the wiggles are pretty minor.
They only go the area slightly more than under foot.
NAS are the skis.
What about forgetting normal sidecut and using and inverse side cut rockered pow stick with camber and this crazy wavy edge.
Increasing the contact points with a smaller effective edge would give considerable more control on the hard.
I saw some the other day at BB. I will be investigating further.
Re: libtech
lib tech is, at least in my opinion, one of the most innovative "commercial" brands together with line. their concepts are just way ahead!
lib tech is funny - narrow ass snowboards, this is why you really have to order TWO skis, they only sell as single. i like this idea
but now for magnetraction. i mean the idea behind it is kind of logical, by reducing the contact lenght of the edge with this wavy thing you get far more pressure in the "tips" of the edges. and so far more grip.
but... i don`t know what to think about it. it`s logical, but somehow i have difficulties to imagine how it should work when such skis carve... furthermore i had no idea of how to dimension the wiggles. looks like 5 is the number to go and underfoot more offset than to tip/tails. and by the way: i think you had to prebend the wiggles a little, so this extra work is maybe keeping me from trying magnetraction lazy ass haha
on the forum of graf snowboards i remember having seen someone who built such skis. maybe i`ll get back on him sometime and invite him over here to share
lib tech is funny - narrow ass snowboards, this is why you really have to order TWO skis, they only sell as single. i like this idea
but now for magnetraction. i mean the idea behind it is kind of logical, by reducing the contact lenght of the edge with this wavy thing you get far more pressure in the "tips" of the edges. and so far more grip.
but... i don`t know what to think about it. it`s logical, but somehow i have difficulties to imagine how it should work when such skis carve... furthermore i had no idea of how to dimension the wiggles. looks like 5 is the number to go and underfoot more offset than to tip/tails. and by the way: i think you had to prebend the wiggles a little, so this extra work is maybe keeping me from trying magnetraction
lazy ass hahaon the forum of graf snowboards i remember having seen someone who built such skis. maybe i`ll get back on him sometime and invite him over here to share
plywood freeride industries - go ply, ride wood!
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Wannabebuilder
- Posts: 60
- Joined: Sat Oct 20, 2007 8:22 am
Those lib techs are some of the stiffest skis I have ever flexed.
Explosive stiff ++ x-tra.
Fair amount of camber.
big ass profile, large core.
Very little sidecut, good for pow.
I was not a believer till I actually held the ski, the waves are much less dramatic and makes more sense when you see it applied.
The guy said they rail. I guess he likes groomers.
My first impression was "how are they not squirly at speed?" but that must be where the stiffness comes in .
I wonder if y'all could hypothesize on that.
Explosive stiff ++ x-tra.
Fair amount of camber.
big ass profile, large core.
Very little sidecut, good for pow.
I was not a believer till I actually held the ski, the waves are much less dramatic and makes more sense when you see it applied.
The guy said they rail. I guess he likes groomers.
My first impression was "how are they not squirly at speed?" but that must be where the stiffness comes in .
I wonder if y'all could hypothesize on that.
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oasisvader
- Posts: 14
- Joined: Tue Jan 29, 2008 11:32 am
Hi guys,
I'm actually working on a rockered design and found this super interesting thread, instead of starting a new one I'll just add my thoughts/questions here !
Last summer I designed a rockered ski, I actually never skied that kind of sticks but I found the idea very interesting to I wanted to give it a try. So I designed it, had the templates and tip&tail molds machined with my other shapes and left it sitting on a shelve 'till a couple weeks ago.
On new years day I finally pressed a rockered ski and although it looks really nice from an artistic point of view I have serious doubts about the ride. The rocker is pretty long but not that high (400x20mm front, 300x15mm back), there is no real tip or tail, regular camber underfoot, regular sidecut going from tip to tail... I'll post pictures later.
If I sit and look at my work I can tell I did think a lot about the look of the ski but not that much about the theory behind it... So I'll give them a try of course but I'm already thinking of an improved design, carefully thought !
The rockered ski I want to make is gonna be used mainly for eastern "backcountry" skiing, meaning it has to be good on powder and trees but still be manageable on packed snow or ice (which will make it a descent ski for resort also).
Here is a small draft of my latest thoughts, dimensions in red are what I plan to do (roughly) but for this thread I'm more interested in the concept behind a rockered ski than this exact shape/dimensions.
As you can see, although there is a rockered tail it's still a directional ski (not pure twin tip), the front rocker will be slightly longer and higher than the tail rocker, same thing for the actual tip and tail.
Some questions : on a rockered ski, what's the running length ? Is it still the length between the contact points or do we also consider the tip & tail rockers ?
As I said in an other thread, when I'm designing a ski I want the binding mounting point to match the narrowest point of the ski, which idealy will be 55% of the RL... I don't know if this is still a good statement with rocker ?
Is it correct to have the widest points of the skis to match the contact points ?
On the skis I design for me (I work a lot with parametric curves and arcs) I took RL1 (Running length = between contact points only) and RL2 (running length = regular camber + tip and tail rocker), I took the 55% point on each one and made them match. This gave me the mounting point and the narrowest point.
Where I'm now having a hard time is when I work on the top view (sidecut), I want my widest points to be @ the contact points BUT the running length (RL1) is pretty short, with the dimensions I want (130-110-120) it gives some pretty tight radius, especially on the front (less than 10m). In the back though I can get a 20ish radius which is fine IMO. Do you think instaed if starting form the dimensions I want (130-110-120) I should start with a radius (let's say 25m or 23m front/26m back) and the width on contact point will be what they'll be ?
That's gonna be it for now I have to go back to work... Thanks for reading and hopefully contributing.
Let me know if you see some major mistake on just what you think.
I'm actually working on a rockered design and found this super interesting thread, instead of starting a new one I'll just add my thoughts/questions here !
Last summer I designed a rockered ski, I actually never skied that kind of sticks but I found the idea very interesting to I wanted to give it a try. So I designed it, had the templates and tip&tail molds machined with my other shapes and left it sitting on a shelve 'till a couple weeks ago.
On new years day I finally pressed a rockered ski and although it looks really nice from an artistic point of view I have serious doubts about the ride. The rocker is pretty long but not that high (400x20mm front, 300x15mm back), there is no real tip or tail, regular camber underfoot, regular sidecut going from tip to tail... I'll post pictures later.
If I sit and look at my work I can tell I did think a lot about the look of the ski but not that much about the theory behind it... So I'll give them a try of course but I'm already thinking of an improved design, carefully thought !
The rockered ski I want to make is gonna be used mainly for eastern "backcountry" skiing, meaning it has to be good on powder and trees but still be manageable on packed snow or ice (which will make it a descent ski for resort also).
Here is a small draft of my latest thoughts, dimensions in red are what I plan to do (roughly) but for this thread I'm more interested in the concept behind a rockered ski than this exact shape/dimensions.
As you can see, although there is a rockered tail it's still a directional ski (not pure twin tip), the front rocker will be slightly longer and higher than the tail rocker, same thing for the actual tip and tail.
Some questions : on a rockered ski, what's the running length ? Is it still the length between the contact points or do we also consider the tip & tail rockers ?
As I said in an other thread, when I'm designing a ski I want the binding mounting point to match the narrowest point of the ski, which idealy will be 55% of the RL... I don't know if this is still a good statement with rocker ?
Is it correct to have the widest points of the skis to match the contact points ?
On the skis I design for me (I work a lot with parametric curves and arcs) I took RL1 (Running length = between contact points only) and RL2 (running length = regular camber + tip and tail rocker), I took the 55% point on each one and made them match. This gave me the mounting point and the narrowest point.
Where I'm now having a hard time is when I work on the top view (sidecut), I want my widest points to be @ the contact points BUT the running length (RL1) is pretty short, with the dimensions I want (130-110-120) it gives some pretty tight radius, especially on the front (less than 10m). In the back though I can get a 20ish radius which is fine IMO. Do you think instaed if starting form the dimensions I want (130-110-120) I should start with a radius (let's say 25m or 23m front/26m back) and the width on contact point will be what they'll be ?
That's gonna be it for now I have to go back to work... Thanks for reading and hopefully contributing.
Let me know if you see some major mistake on just what you think.
A bad day skiing is always better than a good one at work...
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doughboyshredder
- Posts: 1354
- Joined: Mon Sep 17, 2007 7:37 pm
That is not a rockered ski per se. All you have is weird tip shapes and an odd tip profile.
Extend your sidecut in to the rise and that's a rocker. Or conversely bring your tip raise further in towards the center of your sidecut.
If you want to call it Rocker cause it sounds cool that's fine. But, if you want to experience the design phenomenon of rocker then you're going off on a tangent.
Basically you built a 182 with really long tips.
Extend your sidecut in to the rise and that's a rocker. Or conversely bring your tip raise further in towards the center of your sidecut.
If you want to call it Rocker cause it sounds cool that's fine. But, if you want to experience the design phenomenon of rocker then you're going off on a tangent.
Basically you built a 182 with really long tips.
well the scale is absolutely off, everything is exagerated. So is the shape of the tips on the drawing. It was meant to show the different parts of the skis on top and side views to see the relation between them.
For me the rocker was an early rise before a real tip, not a super long tip : in my head I planned having a rise of 20mm over 250mm and after that a real ("regular") tip that would go up to 60mm... but I had no idea how to arrange the sidecut with this. and that's what I'd like to try, I don't want a rocker cause it's fashion, I have this image of the camber/tip shape in my head but it's not that easy to add the sidecut aspect to that.
I take note of extending the sidecut in the tip rise (or starting the rise closer to the ski center).
I just thrown some ideas, nothing is definitive, as I told I never skied with rockered skis so I don't really know what it changes on the ride, and the only rockered skis I've seen basically are on my computer... I'm willing to experience that though so thanks for correcting when I'm wrong.
Could you explain how the rocker affects the ride (what shape does what) ? or just throw a link where it's explained ?
As a side note, when I talk about "rocker" my main reference is not in skiing but comes from the years when I used to make freestyle kayaks, the shape of the hull in the tips is called "rocker" because it rises progressively.
Thanks
For me the rocker was an early rise before a real tip, not a super long tip : in my head I planned having a rise of 20mm over 250mm and after that a real ("regular") tip that would go up to 60mm... but I had no idea how to arrange the sidecut with this. and that's what I'd like to try, I don't want a rocker cause it's fashion, I have this image of the camber/tip shape in my head but it's not that easy to add the sidecut aspect to that.
I take note of extending the sidecut in the tip rise (or starting the rise closer to the ski center).
I just thrown some ideas, nothing is definitive, as I told I never skied with rockered skis so I don't really know what it changes on the ride, and the only rockered skis I've seen basically are on my computer... I'm willing to experience that though so thanks for correcting when I'm wrong.
Could you explain how the rocker affects the ride (what shape does what) ? or just throw a link where it's explained ?
As a side note, when I talk about "rocker" my main reference is not in skiing but comes from the years when I used to make freestyle kayaks, the shape of the hull in the tips is called "rocker" because it rises progressively.
Thanks
A bad day skiing is always better than a good one at work...
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doughboyshredder
- Posts: 1354
- Joined: Mon Sep 17, 2007 7:37 pm
right on. Sorry, if I came across rude. I tend to do that.
From a design perspective rockered areas of the running length "pre-weight" that section of the ski or board. Imagine you are cranking in to a carve on a pair of stiff planks and you have bent out the camber completely and are flexing the ski even further. Full rocker is basically shaping the ski or board so that it is already in this shape. Rockered tips and tails are kind of inbetween. The whole purpose is too make the ski feel looser. Some of the skis with rockered tips also have reverse sidecut in that area which kind of blurrs the lines between rockers and early rise tips.
Regardless, playing around with shapes is fun.
I actually have drawings that I did sometime around 92 of boards that were squared off at the tip and tail with the sidecut extending all the way through the tip and tail rise. I thought they would be good race boards. Now the top race boards pretty much have exactly what I drew in 92.
From a design perspective rockered areas of the running length "pre-weight" that section of the ski or board. Imagine you are cranking in to a carve on a pair of stiff planks and you have bent out the camber completely and are flexing the ski even further. Full rocker is basically shaping the ski or board so that it is already in this shape. Rockered tips and tails are kind of inbetween. The whole purpose is too make the ski feel looser. Some of the skis with rockered tips also have reverse sidecut in that area which kind of blurrs the lines between rockers and early rise tips.
Regardless, playing around with shapes is fun.
I actually have drawings that I did sometime around 92 of boards that were squared off at the tip and tail with the sidecut extending all the way through the tip and tail rise. I thought they would be good race boards. Now the top race boards pretty much have exactly what I drew in 92.
As promised, some pics of my last ski :
http://www.skibuilders.com/phpBB2/viewt ... 4694#14694
http://www.skibuilders.com/phpBB2/viewt ... 4694#14694
A bad day skiing is always better than a good one at work...
ben
I am at the same stage as you in the design work for some rockered/early rise skis.
There are 2 ways to look at the sidecut in this type of ski I reckon (I won't use teh word rocker!). Either have a "normal" sidecut that extends to the normal point in the tip and tail. For fat skis this will mean a pretty large radius arc. The other is to have the sidecut start and end at the contact points with the snow. This second style seems to be what companies are pushing with at present for a true all mountain ski eg. Armada JJ, Rossignol S7.
My opinion is that its important to remember rockered skis at present are primarily powder specific, but people are now thinking that the "rocker/early rise" concept might actually be well suited to all around skiing. K2 actually have a rocker/early rise in some of their beginner skis this year with the idea being that the forward contact point is brought back allowing the tip to not catch and swing into turns easier.
Back on topic:
I think where everyone seems to be going is these earlyrise/rocker tips and tails is ending the side cut at the new contact points (which are closer to the ski's centre than a traditional ski). The skis in powder float because of the width of the skis and the tips don't dive because they are turned up further and you end up riding more on the snow than down in it. The major benefit with the shortened sidecut in the actual running length (when placed on a flat surface the area between the two points that actually touch the ground) is that it has to be a more aggressive arc. That is a fat ski with a 115 waist and 130 or 140 tips can actually have a sidecut radius of somethingt like 18m or so, rather than 25 or so in a traditional shape. This means that on the hardpack between powder and chairlift the skis are actually quite agile and carve well. And people are actually skiing these skis on non powder days too.
One of the reasons I've started building skis is to make something to help my girlfriend ski powder better (admittedly $700 on a pair of commerical skis would have turned out a lot cheaper, but we all need a hobby!). She is quite small and I worried about her ability to ski a traditional powder ski with fat waist and tips and a large 20m+ sidecut. The beauty of the early rise/rocker tip and tail design with sidecut in only the running length is that she can have the fat ski in the waist, tip and tail, but the actual sidecut will be pretty much the same as her K2 missdemeanours and therefore the ski back to the lifts shouldn't be a huge chore.
These are my theories.
The one thing I am thinking is that I might start and end the sidecut just beyond the projected contact points into the tip and tail. I am worried that if teh pressing is a little out of allignment (in the tip to tail direction) that if the sidecut goes from normal into a transition to the narrowed tips and tails before the ski actually stops contacting the ground then they may ski pretty weird. So I'm thinking the widest points in my design will be 2 or 3 cm (maybe5?) beyond where the actual contact points will be. This will make the radius of sidecut sluightly larger, but I think a bit safer than the risk of the skis being catchy at the tail and just weird at teh tip when skiing.
I am at the same stage as you in the design work for some rockered/early rise skis.
There are 2 ways to look at the sidecut in this type of ski I reckon (I won't use teh word rocker!). Either have a "normal" sidecut that extends to the normal point in the tip and tail. For fat skis this will mean a pretty large radius arc. The other is to have the sidecut start and end at the contact points with the snow. This second style seems to be what companies are pushing with at present for a true all mountain ski eg. Armada JJ, Rossignol S7.
My opinion is that its important to remember rockered skis at present are primarily powder specific, but people are now thinking that the "rocker/early rise" concept might actually be well suited to all around skiing. K2 actually have a rocker/early rise in some of their beginner skis this year with the idea being that the forward contact point is brought back allowing the tip to not catch and swing into turns easier.
Back on topic:
I think where everyone seems to be going is these earlyrise/rocker tips and tails is ending the side cut at the new contact points (which are closer to the ski's centre than a traditional ski). The skis in powder float because of the width of the skis and the tips don't dive because they are turned up further and you end up riding more on the snow than down in it. The major benefit with the shortened sidecut in the actual running length (when placed on a flat surface the area between the two points that actually touch the ground) is that it has to be a more aggressive arc. That is a fat ski with a 115 waist and 130 or 140 tips can actually have a sidecut radius of somethingt like 18m or so, rather than 25 or so in a traditional shape. This means that on the hardpack between powder and chairlift the skis are actually quite agile and carve well. And people are actually skiing these skis on non powder days too.
One of the reasons I've started building skis is to make something to help my girlfriend ski powder better (admittedly $700 on a pair of commerical skis would have turned out a lot cheaper, but we all need a hobby!). She is quite small and I worried about her ability to ski a traditional powder ski with fat waist and tips and a large 20m+ sidecut. The beauty of the early rise/rocker tip and tail design with sidecut in only the running length is that she can have the fat ski in the waist, tip and tail, but the actual sidecut will be pretty much the same as her K2 missdemeanours and therefore the ski back to the lifts shouldn't be a huge chore.
These are my theories.
The one thing I am thinking is that I might start and end the sidecut just beyond the projected contact points into the tip and tail. I am worried that if teh pressing is a little out of allignment (in the tip to tail direction) that if the sidecut goes from normal into a transition to the narrowed tips and tails before the ski actually stops contacting the ground then they may ski pretty weird. So I'm thinking the widest points in my design will be 2 or 3 cm (maybe5?) beyond where the actual contact points will be. This will make the radius of sidecut sluightly larger, but I think a bit safer than the risk of the skis being catchy at the tail and just weird at teh tip when skiing.