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Two skis or one?

Question for the experts - I am no expert, and I didn’t sleep in a Holiday Inn last night. I guess I am a strong intermediate - I ski any piste and shallow powder with confidence, control, and speed. My question is about skiing on two feet instead of one. I was taught to carve a turn, not skid, you bend your ski by leaning forward and ride the bent ski(s) around the turn. The max amount you can bend the ski(s), which defines the shortest radius turn, is based on the amount of pressure you exert forward and is limited by your body weight and centrifugal force. It would appear that if you apply all your weight and centrifugal force to one ski you can bend it more than if you equally divide it between two skis. Said another way, it would be easier to get the same bend on one ski than two. So if you ski on one ski instead of two you can carve a shorter radius turn or you can get the same radius with less effort – right??
I'm not an expert, but I am an expert on that aspect of skis.

What you say is true, but it is only needed if you are on very stiff skis and moving at very slow speeds, like making the turn at the top of the lift on my old sg skis. The modern skis are soft enough that the natural decambering effect of your weight in the middle of them will decamber them enough and all you need do is tip them on edge.

Also on hard snow, the side cut of the modern ski combined with simple tipping will decamber them to just the right shape so that you can carve a purer arc than you could by forcing the tip to bend more with forward pressure. The skis are designed to turn at a very small radius without needing to resort to such tactics, unless you weight 100 lbs and are running a sl course on SG skis.
Research indicate that on flat terrain skiing becomes more one footed (25/75). On steeper terrain skiing becomes more two footed (45/55).

You are right that distributing your weight on one ski makes it bend more and also allow for a tighter carved turn but in skiing you dont always make turns with the same turn radius. In all kind of skiing the ski is some kind of a compromize. Also, bending the ski is one thing, balance and tracktion is annother.
SteveE,

Your assumption is correct that by adding more edge angle/pressure that the ski will bend more, causing it to define a tighter arc. The problem with that is you are moving inside the turn very far to get this effect and the force applied to the ski from that position is pressing down on the ski causing it to overload and chattering on steep terrain that has harder snow. The other problem with edge/pressure oriented skiers is that once the forces subside later in the turn, you end on with your weight on the inside ski which makes a smooth transition into the next turn difficult.

Another solution to tightening the arc is adding some leg rotational force (guidance) to the inside ski as you flex your ankle to the outside of the tongue of the boot. This will move your core in the direction you want instead of pressing downward to move the ski forward through the arc.

RW
It's not a question of applying more force and then turning -- it's a matter of having everything in equilibrium.

There is a limit to how much you can angulate a ski at a given speed and still keep your body upright (ie, not topple over). This speaks to a vertical balance of forces. There is also a limit to how much centripetal force (goes like the square of speed) the ski edges can resist in a corner, which speaks to a lateral/sideways balance of forces. Overall, there is a very narrow range where edge angle, body angulation, gravity, and centripetal acceleration all balance out. In a properly executed turn, our body manages this balance in a very remarkable way.

If you look at the loads that end up bending a ski, it's true that you can bend a single ski easier than putting the same load into two skis. But you have also reduced the footprint on the snow that is supporting your vertical weight and reduced the amount of ski edge that is resisting lateral/centripetal acceleration. So you will likely wash out of the turn sooner on one ski than two. Again it comes down to equilibrium, and you have to weigh "on-paper" physics against real world performance.
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 Originally Posted by SteveE ...My question is about skiing on two feet instead of one. I was taught to carve a turn, not skid, you bend your ski by leaning forward and ride the bent ski(s) around the turn. The max amount you can bend the ski(s), which defines the shortest radius turn, is based on the amount of pressure you exert forward and is limited by your body weight and centrifugal force. It would appear that if you apply all your weight and centrifugal force to one ski you can bend it more than if you equally divide it between two skis. Said another way, it would be easier to get the same bend on one ski than two. So if you ski on one ski instead of two you can carve a shorter radius turn or you can get the same radius with less effort – right??
Yes, you can flex a ski more by pressuring one ski instead of two.

Another major factor determining the turn radius is how much you tip the ski. An easy way to tip your outside ski a lot is to tip your inside ski aggressively (whether it's weighted or not).
Steve,
Here's Manfred Moelgg doing exactly what you suggest:

Of course, a still shot of a racer can capture just about anything...the racer is doing whatever they can to get through the gates and maintain speed & grip.

Note how Moelgg is strongly angulated...his ankles/legs/hips are to the inside of the turn and his body is bent toward the outside of the turn. This helps avoid the edges losing grip and washing out. His angulation also helps...hips and shoulders twisted toward the outside of the turn.

So...load the outside ski until it loses grip, then don't load it quite so much next time. Of course, for deep snow, go 50-50 on the weight distribution. Press forward harder on the boot tongues to start a tighter turn, less hard to start an easier turn. Be in the middle of the boot for the middle and end of the turn, then forward for the next turn.
SteveE, welcome to Epic. On hard snow its good to have your weight on the outside ski for many reasons that have nothing to do with how much the ski will bend, so do that anyway. In powder, crud and other software conditions, then go for more 50/50.

Your pure carve turn radius will be more effected by the edge angle you get from your skis. There is volumes that can be said about how to properly develop bigger edge angles.
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 The max amount you can bend the ski(s), which defines the shortest radius turn, is based on the amount of pressure you exert forward and is limited by your body weight and centrifugal force.
Hi, Steve. Borntoski and RickS already spoke to what I'm going to say. Your primary focus on forward pressure to change turn radius is misplaced. Compared to changing your edge angle, fore/aft pressure distribution will have only minor influence on turn radius.

The higher you tip your skis on edge, the more your skis will bend, and the sharper they'll turn. That's the golden egg of technique you should be pursuing in your goal to decrease your turn radius.

Increasing centrifugal forces will be a byproduct of higher edge angles,,, they are not something you strive to increase on your own, with the intent of sharpening your carve. In this chicken/egg situation, turn shape comes first, and centrifugal forces follow.
Good question and you are right about putting all your weight onto just the outside ski will make it bend more. If you do not have the weight, then you would have to unweight or unload your skis in the transition more to reload them again in the turn. So with technique you can add more weight to it.

Now just because you bend the ski more being on one ski only does not mean your turn is more tight than with two skis. Depending of course on factors like speed, the radius that the ski was build for, the torsional strength of the ski and your actual weight you can put onto your ski in a turn will show you how tight you can go. Should you put too much bend onto your ski that does not match up with the speed, you will skid. If you have not enough pressure on your ski and go too tight on the turn you will skid. It all has to relate to each other.

Also you need to put all you got on your outside ski when you really have an icy slope. As the snow gets softer you would add more and more of your inner ski to the outside ski to get more surface onto the snow so you do not sink in too far. Now "carving" in soft snow is much easier, your edges grab easier so that there is not as much delay to initiate the turn as there would be on ice. That allows you to carve tight turns even though you may not bend the ski as much as you do in an icy pitch. It almost balances itself out so that you are able to perform the same radius in any condition.

On soft snow it certainly appears that it takes less effort to carve a turn, but you have more snow to push out of the way. I think hard and compact snow is probably the best. But the opinion may differ here.

There is probably more to it to explore all that, "Ghost" is excellent with that stuff. He may have a better answer to all that.

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 Originally Posted by SteveE Question for the experts - I am no expert, and I didn’t sleep in a Holiday Inn last night. I guess I am a strong intermediate - I ski any piste and shallow powder with confidence, control, and speed. My question is about skiing on two feet instead of one. I was taught to carve a turn, not skid, you bend your ski by leaning forward and ride the bent ski(s) around the turn. The max amount you can bend the ski(s), which defines the shortest radius turn, is based on the amount of pressure you exert forward and is limited by your body weight and centrifugal force. It would appear that if you apply all your weight and centrifugal force to one ski you can bend it more than if you equally divide it between two skis. Said another way, it would be easier to get the same bend on one ski than two. So if you ski on one ski instead of two you can carve a shorter radius turn or you can get the same radius with less effort – right??
Quote:
 Originally Posted by SteveE My question is about skiing on two feet instead of one. I was taught to carve a turn, not skid, you bend your ski by leaning forward and ride the bent ski(s) around the turn. The max amount you can bend the ski(s), which defines the shortest radius turn, is based on the amount of pressure you exert forward and is limited by your body weight and centrifugal force. It would appear that if you apply all your weight and centrifugal force to one ski you can bend it more than if you equally divide it between two skis. Said another way, it would be easier to get the same bend on one ski than two. So if you ski on one ski instead of two you can carve a shorter radius turn or you can get the same radius with less effort – right??
I am going to go at this question a little different than everybody else.

I agree with Rick and others that tightening the turn by leveraging the skis fore and aft is far less effective than increasing edge angles. I will also say that most skiers have enough body weight to bend both skis in decamber to a large degree. It therefore begs the question of how you can get the maximum edge angles.

Let's take the zero g force static position of standing still. If you are on one ski you cannot get much of anything for edge angles however, if you are on two feet with your feet apart you can get fairly high edge angles simply because you have stability between your two feet. I therefore declare that its intuitively obvious that you can get higher edge angles on two feet than one because you can add the edge angle you can get from centrifugal force to what you can get through stability for a higher overall edge angle. Now if we are going to agree that higher edge angles are the key to tighter turns then two feet is better than one for getting a tighter turn.

That said, there are two caveats. Number one, its far easier said than done and far easier to ski dynamically on one ski than two. Number two, skiing on two skis as opposed to one is almost always slower with higher drag and friction. This means that two skis is not necessarily the fastest way to ski a line.

Controlling turn size by carrying weight on the inside ski (tipping the inside ski to a slightly higher edge than the outside ski)requires very good alignment and very good control of the flow of the body mass throughout the turn. You mechanically have to be over the skis in the right place at the right time 97% of the time or face the splits. Its far easier to carry most of the weight on the outside ski and guide the inside ski. Your edge angles will not be quite as high but you will remain upright.

I hope I have not confused the issue here with pushing the technical envelope but you did post in the Ski Technique and analysis forum.
The answer to the question, do you ski on one foot or two? is yes.

We start (initiation) the turn on two feet, the closer we get to the 70% point (point of maximum force, just below the fall line) the more we end up on one, and the more we move away from that point to the transition (edge change), the more we end up on two again.
Dominance of the outside ski is greater the harder the snow and faster the speed. The slower the speed and softer the snow the more two footed we are to achieve a similar result.
If the movement is contrived it will most likely impede the bodies ability to move inside the arc, fore/aft balance, or leg turning.
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 Originally Posted by jonboylou The answer to the question, do you ski on one foot or two? is yes. We start (initiation) the turn on two feet, the closer we get to the 70% point (point of maximum force, just below the fall line) the more we end up on one, and the more we move away from that point to the transition (edge change), the more we end up on two again. Dominance of the outside ski is greater the harder the snow and faster the speed. The slower the speed and softer the snow the more two footed we are to achieve a similar result. If the movement is contrived it will most likely impede the bodies ability to move inside the arc, fore/aft balance, or leg turning.

That's pretty much what you would naturally do and it works well: transfer most of your weight to the outside ski at the moment of greatest force, keeping just enough weight on the inside ski to keep it tracking in its decambered state and smoothly change to the opposite foot at the next (opposite) apex.

Technically though, you CAN get put more bend into the ski by doing the old-school bend and drive, it's just seldom warranted. What used to be reserved for smooth precise carving with no speed loss due to slipping edges at DH speeds translates moderately well to slower speeds tighter turns on modern skis.
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 Originally Posted by SoftSnowGuy Steve, Here's Manfred Moelgg doing exactly what you suggest: Of course, a still shot of a racer can capture just about anything...the racer is doing whatever they can to get through the gates and maintain speed & grip. Note how Moelgg is strongly angulated...his ankles/legs/hips are to the inside of the turn and his body is bent toward the outside of the turn. This helps avoid the edges losing grip and washing out. His angulation also helps...hips and shoulders twisted toward the outside of the turn. So...load the outside ski until it loses grip, then don't load it quite so much next time. Of course, for deep snow, go 50-50 on the weight distribution. Press forward harder on the boot tongues to start a tighter turn, less hard to start an easier turn. Be in the middle of the boot for the middle and end of the turn, then forward for the next turn.
This is an interesting picture - - but as you say a snapshot can show pretty much anything.

But I was under (the apparently mistaken?) belief that as one turn ends you should move your COM over the skis to release your edges and initiate the next turn. In doing this (if this is correct), won't the upper body/torso be facing more inside the turn than the lower body - - at least initially?

Am I completely confused - - or is this dependent on the "snapshot" itself, with regard to where the skier is in the turn?
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 Originally Posted by RonSki Am I completely confused - - or is this dependent on the "snapshot" itself, with regard to where the skier is in the turn?
Skier passed the gate. You can see the gate behind him.

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 Originally Posted by RonSki This is an interesting picture - - but as you say a snapshot can show pretty much anything. But I was under (the apparently mistaken?) belief that as one turn ends you should move your COM over the skis to release your edges and initiate the next turn. In doing this (if this is correct), won't the upper body/torso be facing more inside the turn than the lower body - - at least initially?
You are completely right. Skier comming out of the turn is countering. After edge change this counter becomes anticipation. That means that the upper body still faces slightly down hill and in the direction of the next gate while skis are still tracking across the hill.
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 Originally Posted by jonboylou The answer to the question, do you ski on one foot or two? is yes. We start (initiation) the turn on two feet, the closer we get to the 70% point (point of maximum force, just below the fall line) the more we end up on one, and the more we move away from that point to the transition (edge change), the more we end up on two again. Dominance of the outside ski is greater the harder the snow and faster the speed. The slower the speed and softer the snow the more two footed we are to achieve a similar result. If the movement is contrived it will most likely impede the bodies ability to move inside the arc, fore/aft balance, or leg turning.
Well said.
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