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Carving both skis

post #1 of 14
Thread Starter 
This is something I've been wondering for a while. The physics don't seem to make sense.

In order to get both skis to carve an efficient turn, the inside ski must carve a smaller radius. How can that work when we're outside ski-dominant or even 50/50?

Even in a railroad track exercise... or clean traverse...

Do we just chalk it up to the likelihood that one of the skis, probably the inside ski, isn't carving as cleanly as the outside? (or vice versa?) It doesn't really feel like that to me, though. It feels as though I'm isolating edging and balancing skills, and pressuring somewhere between outside-ski dominance and 50/50, and I get two parallel arcs.


Thoughts? :
post #2 of 14
No... the inside ski doesn't carve a smaller radius... Look at these 2 parentheses... (( Same radius..
post #3 of 14
Thread Starter 
hydrogen... if you extended those two parentheses to a full 180 degree direction change, (in essence, a half a circle) they won't stay parallel, though. The two lines would intersect at top and bottom.

In order to stay parallel, the inside line radius must be smaller.
post #4 of 14
That's true... they would overlap... but before the overlap is generally where you switch edges, right? I think one issue is that you are considering keeping uniform edge pressure throughout the whole turn, which I doubt every really happens.

I'm not a real strong carver, so I could be wrong..
post #5 of 14
Why are you carving at 50/50? I carve at 90/10. The inside, uphill ski must remain lighter to move up as you progressively tighten the radius.
post #6 of 14
There are many variables. There is no good reason for carve lines that are a constant width apart. Let the skis run in slightly different arcs. Most turns are not 180°. For the actual arc, the divergence usually doesn't matter. The outside ski, being weighted more, will displace snow more, even in a "perfect" carve. Getting more tip pressure on the inside ski helps it carve a tighter turn. Thus you have the current trend of little inside tip lead. We sometimes see racers lifting the tail of the inside ski to get their weight forward for even more tip pressure. More tipping angle of the inside ski will cause it to ski a tighter arc.
Here's Marco Buechel in the Hinterstoder Super G last December.


Ken
post #7 of 14
Thread Starter 
Quote:
Originally Posted by Finndog View Post
Why are you carving at 50/50? I carve at 90/10. The inside, uphill ski must remain lighter to move up as you progressively tighten the radius.

I can carve at 50/50, if the circumstances allow. In fact, there are some (many?) in PSIA who consider 50/50 carving as proper "good" technique, particularly on-piste.

Sometimes, I carve 0/100 on the outside edge of the inside ski. But, like you, I usually carve with more outside-ski dominance, in most of my skiing.

I disagree that the inside ski must remain light to tighten the radius of a turn. There are many ways to tighten the radius of a turn besides shifting more weight to the outside ski.
post #8 of 14
Lets say your width stance inside edge to inside edge is .3m and your skis are R=15m. The difference in required radius between the inside and outside ski 2%. I'm sure various slops (give in the snow, undetectable micro slippage, etc.) allow for the skis to for all practical purposes track parallel over the length of your average turn.
post #9 of 14
Quote:
Originally Posted by Baja View Post
I can carve at 50/50, if the circumstances allow. In fact, there are some (many?) in PSIA who consider 50/50 carving as proper "good" technique, particularly on-piste.
I once had this discussion with a former World Cup skier who eventually became a Volkl Carver Girl. When we asked her about continuously carving both skis, she said "you can't do that." That was just before shape skis were available, when GS skis were starting to have more shape, and coaches were talking about "2 footed carving."
More recently, I had a similar discussion with the current president of PSIA. He agreed you can carve on either ski, but that the most effective way to carve was let pressure build up on the outside ski. When we asked him about how the inside ski can make an arc with a smaller radius that the outside ski, he said the inside ski is less pressured and easily steered. His exact words about the tracks made by the inside ski were "just because a ski is making marks in the snow, that doesn't mean it's doing anything."
There may be "some (many?) in PSIA who consider 50/50 carving as proper "good" technique," but if there are, it only proves the difficulty of communicating with 30,000 members.

BK
post #10 of 14

It's all relative

The distance between the skis is usually small compared to the turn radius of the skis. As in roughly 0.3m compared to 15-22m for most skis. I doubt that is noticeable to most people. If you weighted 50/50, one ski could rail at it's turn radius and the other would be very slightly skidding (emphasis on very slightly).

Think about it -- if you took a ski with a 20m turn radius and got the outside ski railing a perfect 20m radius turn, the inside ski would be forced into a 19.7m radius turn. The difference between the two radii is very small compared to the radii themselves. On the order of 1.5%. Given all the other slop involved in a turn (especially variable surface conditions) I doubt that's noticeable. That is why we can appear to carve both skis in parallel.

This also tells us that the mismatch in inner/outer ski radii would be most noticeable with a wide stance and short skis with a small radius. A tight stance coupled with long-radius skis would be the least noticeable.
post #11 of 14
The sidecut APPROXIMATES an arc of a given radius. The actual curve can have a mobile centre for it's radius, the curve can be tightened at the tip and then at the tails while the tip radius lengthens out, there are many ways to have both skis arc smoothly.

Parallel railroad tracks are like figure skating, a nice exercise, but not a necessity.
post #12 of 14
Well I am a PSIA type and the only time my skis are 50/50 is during turn transition. Also, 1.75% difference in a 15m turn radius is about 2 1/2 feet or .82M. That is a lot of tip lead.

Leaving two clean equal width tracks in the snow seems to be the holy grail of many ski instructors and I think that comes as a result of certification testing where they want to see if you can ski that way. Just because they want to see it in certification testing, does not mean they believe you should ski this way. They test a lot of one footed skiing and don't expect you to ski that way either.

I can demonstrate a rail road track turn where the ski tracks are nice and even but, if I am hauling and having fun, my outside track will be nice but my inside track can vary and be far less than perfect even though I am rock solid on the skis.

I can quite easily tighten my turns to the point where it's nearly impossible to leave a clean track on the inside ski. I have skis that that have a 17M turn radius and anything below the point where my hips reach about 16 inches above the snow, I cannot leave a clean line. The turn radius gets too small, the G forces get too high or there is interference from the various fat parts of my body. Any way you cut it I have not been successful. Have I tried? yes.

I asked a mentor of mine earlier this year to take a look at my skiing and determine why my inside ski was diverging in carved turns. His answer was "You are on a bunny hill, you have your skis on very high edge, your hips are 10-12 inches above the snow, you are turning perhaps a 10 M radius turn with GS type skis, your inside ski is not diverging but hogging out a wide path and you want me to tell you what is wrong with your skiing? What's wrong is in your head, back off the throttle and the problem will go away. Is it necessary for you to always get the last drop out of a bunny hill? A lighter touch is better and your skiing will look better". My answer was " Buuuut I like the feel of that turn". His answer was "You can only get so much out of a bunny hill. You might like that turn but it's screwing up your skiing by introducting upper body contortions that will carry over into all the rest of your skiing and into the steeps. You asked for my opinion now stop it. "

I did stop, went back to a lighter touch and my body is happier but now I have been told that I have that awful PSIA examiner look to my skiing instead of the PMTS look. If I want pazzaz I guess I will just have to get off the bunny hill.

The point here is that I was skiing a turn radius well below the skis natural radius, I was finishing my turns well across the fall line to get power out of a bunny hill. The result was no way could I adjust the pressures fore/aft or laterally to get that inside ski to carve a clean edge. Sometimes we get caught up in thinking along the lines that PSIA promotes the skiing we do in certification testing but that is really all bullpucky. 50/50 or clean carves do not necessarily mean good technique or bad technique.

Sometimes yeah just gotta shut up and ski.
post #13 of 14
Pierre's friend said-Is it necessary for you to always get the last drop out of a bunny hill? Pierre-I'm chip off the old block. I even turn into the lift line.:
post #14 of 14
Quote:
Originally Posted by Pierre View Post
His answer was "You can only get so much out of a bunny hill. You might like that turn but it's screwing up your skiing by introducting upper body contortions that will carry over into all the rest of your skiing and into the steeps. You asked for my opinion now stop it. "

From all of us stuck on the "Bunny Mountain", thanks for the timely advice.
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