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Why do skis still have camber?

post #1 of 30
Thread Starter 
Kiwiskis thread made me think about this. Why do skis still have camber? The only thing I can think of is "that is the way we always" did it. I can see, back in the day, camber was designed to compensate for the inferior materials at hand. I am not saying all skis need to be reverse camber, but do we need camber at all?
post #2 of 30
Some of us like the feeling of being thrown into the air when the skis de-flex. The camber just adds to that.

Or maybe not...I assume the camber allows the ski to de-flex more readily or at least more completely and provide that "energy".
post #3 of 30
Slingshot.
post #4 of 30
In most situations I like some camber in my ski. I can feel a level of livelyness from a ski with some camber. And at 200 pounds I think I am pretty much starting from zero anyway when I stand on a ski.

I think we a are going a little silly with the no camber deal.

How far do you have to bend a no camber ski to get some POP when you transition from one turn to another.

My LP's even feel a bit slow comming of the old wieghted ski transitioning to the other. I kinda have to yank the ski up rather than control an aggressive cross under that a snappy (Cambered) ski will provide

I liked the livley feel of the original 179 Bro's better than the second gen 2mm camber I have now.
post #5 of 30
Thread Starter 
Quote:
Originally Posted by bjohansson View Post
Some of us like the feeling of being thrown into the air when the skis de-flex. The camber just adds to that.

Or maybe not...I assume the camber allows the ski to de-flex more readily or at least more completely and provide that "energy".
Quote:
Originally Posted by slider View Post
Slingshot.
That is a by-product of it. If you flex a ski int a trough of a mogul it will still do that too.
post #6 of 30
The camber in most Alpine skis is negligable in a turn. It can be squeezed out with two fingers, so it is not much of a factor compared with the flex one creates on edge. It is enough to add a bit of tip and tail pressure on a flat outrun, giving a bit less tip wander.

Pick up a pair of XC racing skis sometime. They have camber which gets stiffer toward the middle, and can not be flattened out with two hands. It is enough to pick the skier right off the snow when weight is on both feet. It keeps the kick wax from sticking in classic skis, and pins the tip and tail down in skating skis. That is real camber.

I think the camber in Alpine skis is for the most part a vestige of ski evolution.
post #7 of 30
I think it is all due to edge grip and that pop that gives a quick edge-to-edge transition on packed trails. But having the tip and tail searching for grip that isn't there in softer snow makes the ski squirrly and unpredictable. And as Phil said, with modern materials and construction camber is far less necessary, even on piste. I think in the not too distant future the amount of camber a ski has will be a function of the width and mix of on/off piste skiing the ski is intended for. My guess would be:

<85mm waist = skinny groomer ski = regular camber or slightly less than now
86mm-105mm waist = all mountain ski = zero camber or mini-rocker
>106mm waist = soft snow ski = full rocker
post #8 of 30
Quote:
Originally Posted by newfydog View Post
The camber in most Alpine skis is negligable in a turn. It can be squeezed out with two fingers, so it is not much of a factor compared with the flex one creates on edge. It is enough to add a bit of tip and tail pressure on a flat outrun, giving a bit less tip wander.

Pick up a pair of XC racing skis sometime. They have camber which gets stiffer toward the middle, and can not be flattened out with two hands. It is enough to pick the skier right off the snow when weight is on both feet. It keeps the kick wax from sticking in classic skis, and pins the tip and tail down in skating skis. That is real camber.

I think the camber in Alpine skis is for the most part a vestige of ski evolution.
I think you're focused in the right direction here. My guess is that it adds functional tension (or pre-loading) which keeps the tip and tail intact with the surface when mass is placed in the center of the ski.

Take any long perfectly straight item and place something of comparably heavy weight in the center of its length. Eventually each end will rise compared with the center. Camber usually does degrade over time, but enough usually remains that prevents tip or tail from pulling off the surface when weight is placed in the center of the ski. Even if it was just a fraction of a millimeter, can you imagine how much more difficult it would be to get a ski tip to engage on a hard surface if the camber's "pre-loading" was missing and the tip pulled up off the surface of the snow?
post #9 of 30
Camber is just like pre-stressing concrete with cables under tension, or the I-beams under a flat-bed being concave-down when there is no load. The reason is so that the ski carries the load out to the tips and tails instead of having it all underneath. In the old days a lot of camber was needed so that under load the right amount of load made it out to the ends. With modern materials, I don't think you need as much.
post #10 of 30
My Wateas have virtually no camber. They are an excellent ski in powder and crud but are absolutely horrible on hard pack. I love them in the deep but there are without a doubt the worst carving skis I have been on in 25 years. I credit it to the absense of camber combined with my 215 lb weight.
post #11 of 30
Thread Starter 
Quote:
Originally Posted by mudfoot View Post
My Wateas have virtually no camber. They are an excellent ski in powder and crud but are absolutely horrible on hard pack. I love them in the deep but there are without a doubt the worst carving skis I have been on in 25 years. I credit it to the absense of camber combined with my 215 lb weight.
I think this has to do more with lack of sidecut and torsional rigidity than camber.
post #12 of 30
Actually they have a lot of torsion rigidity, and I have skied more than a few skis with the same long radius sidecut. Their soft flex doesn't help, but with my weight they feel like the tips and tails aren't even touching the snow because they are flat to begin with.
post #13 of 30
I got the feeling that the camber is one of the contributors to the "pop" you get out of a traditional ski. I think I'd miss that.

Different technology for different purposes.
post #14 of 30
Quote:
Originally Posted by trekchick View Post
I got the feeling that the camber is one of the contributors to the "pop" you get out of a traditional ski. I think I'd miss that.

Different technology for different purposes.


Some of my "poppiest" skis have camber which can be flattened out with about 5 lbs of pressure. How is that contributing anything to popping my 180 lb carcass off the snow?
post #15 of 30
Camber/rebound are definitely not all that linked as newfydog points out. The original reason for camber that Ghost describes is quite accurate.

But why do skis still need significant camber? Well, my skis that are nearly flat almost all started out with more camber. Modern materials or not, they have crept in shear. "Creep" is probably the wrong term to use, as it probably happens over the course of many short but large overloads, like skiing bumps, standing over a crack and bouncing, hitting a hole in the snow with the tip, etc. If you built a ski of the same materials and skied it the same way but it had no camber to begin with, it would end up bent/rockered. Even very slightly bent skis are awful on hard snow.
post #16 of 30
It's purpose is really quite simple and is one of the considerations for choosing the correct ski length. Let me elaborate. First the basic purpose for camber is to distribute the skier's weight as evenly as possible over the length of the ski. It is important that the stiffness of the ski and the camber match the skiers weight, ability, and aggressiveness so that the loads that skier will place on the ski will not overflex or underflex the ski. Think about it, should three different size skiers (one weighing 100lbs, one 200lbs, and one 300lbs) were to stand on a particular ski. The 100lb skier may not have enough weight to even flatten the ski which would cause excessive proportion of weight distributed to the tips and tails and cause the ski to be difficult to turn or decamber. The 300lb skier would probably decamber the ski just standing still on the snow causing the tip and tail to be unweighted while the excessive portion of the skier's weight would be underfoot. This ski would become very unstable for obvious reasons. Now when the 200lb skier stands on the ski the weight is distributed evenly over the whole length of the ski and once moving down the slope the ski decambers easily into an arc but at speed still offers appropriate stability.

This reminds me of another recent thread about short skis vs. longer skis. When choosing a ski length this is an important aspect to consider. When skiing a particular model ski and deciding on ski length the salesperson and/or you yourself should consider your weight, skiing ability, and aggressiveness to match the appropriate ski length. Manufacturers make longer ski lengths in a particular model progressively stiffer as the length increases to help match the size of the skier using them and distribute the skier's weight more evenly over the ski.

Historically ski length has been chosen by a skier's height. When when Salomon introduced their first skis in 1990, they chose a more accurate method called the "power rating" which gave the most consideration to the skier's weight, second most to the skier's ability level, and a lessor value to the skier's aggressiveness. This matched the skier to the appropriate power rated ski. Remember the PR8's were the longest length ski. A PR8 3s slalom was about a 203cm and a PR8 1s GS ski was about a 208.

Think about it, two skiers of equal height (6' 0") could need different length skis if one weighed 250lb and the other 150. Using the Power Rating system they would end up with the appropriate PR ski.

One of the main ways to tell your skis are shot is the resistance of the camber is lost. The core and the fibers around it have broken down to the point they lose camber and not longer can distribute the skier's weight proportionately over it's length. The skis feel dead, and unstable at speed.

camber distributes weight over the ski's length.
post #17 of 30
Quote:
Originally Posted by Garrett View Post
Camber/rebound are definitely not all that linked as newfydog points out. The original reason for camber that Ghost describes is quite accurate.

But why do skis still need significant camber? Well, my skis that are nearly flat almost all started out with more camber. Modern materials or not, they have crept in shear. "Creep" is probably the wrong term to use, as it probably happens over the course of many short but large overloads, like skiing bumps, standing over a crack and bouncing, hitting a hole in the snow with the tip, etc. If you built a ski of the same materials and skied it the same way but it had no camber to begin with, it would end up bent/rockered. Even very slightly bent skis are awful on hard snow.
Maybe you would not build it with the same materials & construction...

Maybe "even very slightly bent skis are awful on hard snow" because they were designed with a specific degree of camber as part of the equation...

I like kiwiski's observations regarding skis for different uses. I'm not sure it'll play out exactly that way - but I think he's on the right track. I bet we see an assortment of rockered/flat/progressive designs in the mix for a range of uses besides powder in the next few years. It'll evolve from there. My guess is that the "all mountain" ski of five years out will have a clear family tree linkage to the spatula via something like a Hell Bent or Melee or EP Pro.
post #18 of 30
Your skis all have camber because you aren't using them enough before you bring in replacements.
post #19 of 30
Quote:
Originally Posted by bud heishman View Post
It's purpose is really quite simple and is one of the considerations for choosing the correct ski length. Let me elaborate. First the basic purpose for camber is to distribute the skier's weight as evenly as possible over the length of the ski.
Bud, I think you need to revisit your typing or your thinking on this. Put a cambered ski flat, or on edge, or whatever. Pressure it with your hand in the middle or toward the front. What do you observe? I'll bet you a nickel it is not even pressure distribution... Heck, the more cambered and stiffer the ski, the less even the pressure distribution will be.
post #20 of 30
Quote:
Originally Posted by bud heishman View Post
First the basic purpose for camber is to distribute the skier's weight as evenly as possible over the length of the ski.
Can't this purpose also be served by the distribution of the flexural stiffness of the ski?
Quote:
One of the main ways to tell your skis are shot is the resistance of the camber is lost. The core and the fibers around it have broken down to the point they lose camber and not longer can distribute the skier's weight proportionately over it's length. The skis feel dead, and unstable at speed.
I can't think of many recent skis I can't close the camber on with my hand grip, even new. Maybe burly men's downhill skis? I question whether camber is as important as you are making it out to be, but modeling the deflection and load distribution of a ski with any semblance of accuracy doesn't sound particularly easy to me so I'll have to take your word for it.
post #21 of 30
Quote:
Originally Posted by spindrift View Post
Bud, I think you need to revisit your typing or your thinking on this. Put a cambered ski flat, or on edge, or whatever. Pressure it with your hand in the middle or toward the front. What do you observe? I'll bet you nickel it is not even pressure distribution... Heck, the more cambered and stiffer the ski, the less even the pressure distribution will be.
What he is saying is congruent. Snow is not an infinitely stiff platform. A ski with uniformly soft stiffness and no camber will not have an even load distribution on the snow. Most of the load will be under the binding. Adding camber moves that load away from the binding...see: any classic nordic ski.

bud also correctly points out that stiffness is a big part of it. I'm just wondering aloud how much you need camber in order to achieve the goal when you can vary the second moment of area and the elastic modulus along the length of the ski. Again, not something I'd want to try and model. I can only say anecdotally that I have skis with "weak" camber that are stable and have plenty of snap. I've had skis that were snappy and had lots of camber and were hard to close, but those skis were just plain stiff anyways.
post #22 of 30
Obviously the camber helps going over crests. A totally flat ski would loose much of its edge, feeling like a snowblade or worse.
post #23 of 30
I have felt camber go away as skis have gotten older. I don't like that on my carving sticks.
post #24 of 30
Quote:
Originally Posted by spindrift View Post
Maybe "even very slightly bent skis are awful on hard snow" because they were designed with a specific degree of camber as part of the equation...
Um, no. Skis rockered for a considerable portion of their length will always blow on hard snow compared to skis that aren't. For trivially simple reasons: Fully rockered skis will always require careful centering and have lousy edge grip. When you pressure the tip or tail of a rockered ski you dramatically shift the center of pressure on the edge with a small movement. Not good for control. A flat/cambered ski with a long rockered tip/tail is just a crappier/heavier version of a short ski on hard snow, with lots of material vibrating freely without contact with the snow surface to damp it. (Ex: Hold a cambered ski against the wall. Pull the tip and let go. Do this with a long rockered tip. Guess which one is damped better.) None of these simple realities are going to magically change when you make the skis of something else.
Quote:
Originally Posted by Carl R
Obviously the camber helps going over crests. A totally flat ski would loose much of its edge, feeling like a snowblade or worse.
On the other hand, a stiff ski with too much camber can hook when going over a roller without much speed. Anytime you find yourself with a ski on edge and loaded that still has camber you are in trouble.

You really have to ski a ski with too much camber and too much stiffness to get an idea of how bad it can be. Find a really long/stiff pair of classic xc skis and try it. You'll never have this happen with first tier alpine skis made in Europe, even if you buy something pretty darned inappropriate for your weight. Much more likely buying stuff made in someone's garage.
post #25 of 30
Quote:
Originally Posted by trekchick View Post
I got the feeling that the camber is one of the contributors to the "pop" you get out of a traditional ski. I think I'd miss that.

Different technology for different purposes.
Quote:
Originally Posted by newfydog View Post
Some of my "poppiest" skis have camber which can be flattened out with about 5 lbs of pressure. How is that contributing anything to popping my 180 lb carcass off the snow?
As I said, its one of the contributors.

Quote:
Originally Posted by Garrett View Post
Camber/rebound are definitely not all that linked as newfydog points out. The original reason for camber that Ghost describes is quite accurate.

But why do skis still need significant camber?
I think its been proven that ALL skis don't need camber. But there will always be some skis with camber as part of the design because of the properties that camber lend to its purpose. Just like Powder skis perform better because they have reverse camber.
post #26 of 30
Bud's post is absolutely correct....skis with no camber pretty much suck on packed snow.
post #27 of 30
Quote:
Originally Posted by Garrett View Post
Um, no. Skis rockered for a considerable portion of their length will always blow on hard snow compared to skis that aren't. For trivially simple reasons: Fully rockered skis will always require careful centering and have lousy edge grip. When you pressure the tip or tail of a rockered ski you dramatically shift the center of pressure on the edge with a small movement. Not good for control. A flat/cambered ski with a long rockered tip/tail is just a crappier/heavier version of a short ski on hard snow, with lots of material vibrating freely without contact with the snow surface to damp it. (Ex: Hold a cambered ski against the wall. Pull the tip and let go. Do this with a long rockered tip. Guess which one is damped better.) None of these simple realities are going to magically change when you make the skis of something else.

My initial response was in response to what I interpreted as a statement about conventional skis that were worn out or bent.

However, I think you are underestimating what can be done with "rockered" designs. Will they have more of a tendency to have floppy tips when running flat on hardpack? Looks like it. However, on anything other than hardpack, the running length effectively increases as the ski (even flat) pressures into the snow. Also, consider the impact of where and how steeply the rocker rises -- and how it relates to sidecut - in the case of a Hell Bent style ski for example. Given the right sidecut and rise, it won't take much angle to engage the rockered component as part of the carving edge of the ski. It may take some technique modifications. It may never match a "stiff" cambered ski on glaze ice -- but the right designs combined with appropriate technique may well break through some stereotypical expectations. My inuition is that some much more all-around designs will come out of this.

It'll be interesting to see what happens as people start using more, and more kinds of, "rockered" and even "flat" skis this year.

Oh, BTW, I think this is an interesting little video. Don't let the fatness of the ski (or its particular orientation) make you lose sight of the interesting parts of the discussion...

post #28 of 30
Great question, great video, sprindrift. My .02: We have camber cuz

1) Flat skis feel flat. Whatever they're made of. In fact, they feel a lot like the quality most people criticize in Rossis - "Not enough energy."

2) We still have camber because most people still ski groomed most of the time. Not bumps, not deep pow, and definitely not Alaskan/BC peaks. So they like the extra help in transitioning, the "lively" feel, which also makes up for their inability to deeply flex a ski.
post #29 of 30
Thanks for posting that vid. Beautiful skiing. The skis are pretty sweet. I have no doubt that designs like that will dominate soft snow skis.

What you say about engaging the rockered part of the ski is interesting. In that video he shows why the sidecut reverses in the rockered section to avoid the unstable hooker phenom. Most skis meant for hard snow have their widest parts beyond the contact points...which really makes for skis that hook up, but also makes them sketchy in crud and adds to the rooster tail effect. It seems like the goals here require opposing solutions for hard and soft snow. The design shown in that video with the "reverse" sidecut through the rockered sections guarantees those sections will never engage at any edge angle on hard snow.

I just got what seems like a really cool idea from thinking about this. Now I need to go play search-the-intertubes to find out how many others already have this idea/patented/marketed it without my knowledge.
post #30 of 30
Unstable hooker! Now you've got my full attention!
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