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Getting Rid of Excessive Inner Ski Tip Lead

 Poster: A snowHead
Poster: A snowHead
veeeight wrote:
So have you yet accepted that the inside ski does not prescribe a smaller radius?

Nevermind the paper - the arcs in the snow tell a different story.

As does the small pile of mouse droppings the lays between your ears Madeye-Smiley
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Masque, there's no need to insult mouse poop in that way. wink
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Masque, indeed. Someone still cannot see that just because two lines look identical and are next to each other - does not mean that they are parallel. Never mind Sad

PJSki, nice to see you back. snowHead

FtS - never had you down as a troll
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So, put yer monies where yer mouths are.

1. Are clean arc to arc ski tracks parallel or identical in the case of park and ride skiing?
2. Are clean arc to arc ski tracks parallel or identical in the case of dynamic carved turns?
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veeeight, (God forgive me for posting this)

In the simplest of explanations, the skis may well stay equidistant from each other and describe . . . for whatever length of time . . . parallel tracks, their radii (though narrowed because you are traversing a cone) are different. The simple fact that the skis are side by side and not in tandem on the same track defines this.

1: In a simple example they can be described as "parallel" but since they are both describing different arcs of concentric circles . . they cannot be identical . . . the inside ski is Earth, the outer is Mars. In a simplistic map of the Solar System they are parallel tracks . . .last thing they are is identical.

2: Because a skier's mass puts its force into the hill through two points of contact but also has it's own centre of rotation above them (not quite sure that's the right term as we are, moving in 4 dimensions), there are at least three fulcrum points on the hill where the radii of the skis track's and the body's track intersect on a moving path over the hill.

Your questions are specious as they only ask for an explanation to a nuance of technique/skill that both demonstrate the same fundamental fact that two skis . . . unless being used by a really good telemarker . . . do not describe identical arcs.

Leaving aside the trigonometry; If you find yourself at the North Pole, place your hand on it and walk around it . . . you've circled the World. Then you start the same journey at the Equator . . . this may well be described as a parallel path, but if anyone says the radii are the same then they are only defining their base ignorance and that will deservedly colour other peoples opinion of them. Both geometrically and dynamically, two tracks can never be the same. If they are linked through a single point then they will have a mathematical/mechanical relationship.

The vast majority of this forum don't give a fig about the definition of that relationship, they only want to know about what will work to make them a better skier. But if the people who profess to have the skills to make them a better skier are unable to either understand the basic mathematics of bodies in motion, or even worse, cannot explain technique without misstating or obfuscating simple facts . . then, however sincerely they believe otherwise . . . they are frauds.

By all means teach, and if it works keep teaching. But don't use pseudo science to create a USP.


Last edited by Anyway, snowHeads is much more fun if you do. on Sat 8-11-08 0:49; edited 3 times in total
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Masque, man, you're weak Wink
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Masque, very nicely done.

In the words of Mr C. Eastwood - A man's got to know his limitations...
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Masque, well done, I understood almost all of that and I am a terrible dunce when it comes to maths and physics.

Any bets on how many new pages this resurrected thread will generate? veeeight is nothing if not tenacious!
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Quote:

since they are both describing different arcs of concentric circles . . they cannot be identical .

And this.... is the start of the fundemental misunderstanding of many on here.

If you care to look back through the many pages on here (even GrahamN has stated) - ski tracks exhibited are not in fact concentric circles, but identical tracks (in many cases).

As for improving peoples skiing, alas, I cannot do that if they insist that ski tracks are concentric circles with a common centre, where the inner track has a smaller radius.

As for your lovely description of parallel circles made by the solar system, unfortunately, due to pack mentallity and other factors, many people now cling to this incorrect analogy in the misunderstanding that they actually know whats going on with their skis - a bigger dis-service to learning on this forum!

Since they hold true to this sadly misguided thought there is nothing I can do to persuade people that trying to get your inside ski to prescibe a smaller radius that your outside ski is in fact a lost cause in good skiing.

If you really are interested, you'd look up one of the latest Greg Grushman (current WC coach, and Technical Consultant to several national teams in Europe) articles where he too talks about the outside ski prescribing a tighter radius in WC skiers (exploring different reasons why this is the case).

And I quote:
Quote:
Thus, an outside ski carves an arc of a tighter radius than the inside one



Unfortunately with the entrenched views that some have with circles on paper in two dimensions with fixed radii, name calling/insults, point scoring and trolling, this thread has far outlived its usefulness in terms of any skking related learning and nderstanding, and only serves as troll bait.


Last edited by You'll get to see more forums and be part of the best ski club on the net. on Sat 8-11-08 8:14; edited 6 times in total
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Masque, one of the best explanations so far on this thread, but mate, you've got to know when to give up - I didn't even buy a ticket for this ride, just waved from the sidewalk a couple of times Very Happy

stoatsbrother, like I said on page 18 wink
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V8 is this the article you're referring to?

http://www.youcanski.com/273/

Greg G. is no little bit like the late Danny Gatton: we appreciated neither one very much* when they were local.



* compared to their reputation elsewhere.
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veeeight,
Quote:
If you care to look back through the many pages on here (even GrahamN has stated) - ski tracks exhibited are not in fact concentric circles, but identical tracks (in many cases).


It makes no difference if we are talking about circles or arcs, because if they are identical, they cannot be parallel. So masque's example works just as well even with elliptical orbits.
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Embarassed I only highlighted this thread due tn a certain 'boring' thread.
Lord have mercy upon my soul.
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slikedges, indeed - great minds etc etc.

veeeight, I am afraid it has revealed rather more about you Sad
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veeeight, And so it continues . . . there is only ONE truth in this tread . . . the ever changing criteria demanded by idiots for others to provide proof that they are idiots.

Skiing is a 4 dimensional activity (and with the inclusion of Yagermeister, possibly five) but I'll try to explain in terms that even the most fixated anal gazer might understand.

The first problem with any description of the process of skiing is the existence of two skis . . . It is an 'Inconvenient Truth' that we have two legs. We boarders make a good fist of pretending that we're monopedal(?) but even we have to find some way to get to the Poma.

Secondly, in all of this thread there seems to be both an obsession with and a rejection of applied physics that I think, from both sides, disrespects the legacy of Newton, Hooke, Kepler et al. The rejecters cannot think beyond a strict simplicity of two objects joined at the groin being the same . . . and the science proselytites that are unable to provide an acceptable explanation to the process of 'falling with style' down the hill.

There is only ONE constant throughout the process of skiing, boarding, sledging, falling off a table when dancing in yer ski boots and that's the journey of your 'Centre of Mass' (CoM) . . . easy to calculate in a sphere on a linear track but more problematic in a skier as we're constantly flailing our extremities in an attempt to keep that mass in balance against variable forces put into our environment by our body's predilection to and rejection of falling to our death down a snow covered mountain.

When all the forces are combined into one unit there is one path (or track) where the CoM makes its way to the next lift. The two points of contact with the hill (your feet, for those struggling to keep up) can only be identical if you're in a constant state . . . either at a standstill or in free-fall down the fall-line.

So, I'll try to eliminate the minutiae from the multitude of variables and describe the path of a skier down a flat plane set at a fixed angle to the horizontal . . .

I think we all accept that the outer and downhill ski should be pressured more than the inner or uphill ski. That downhill ski will be, to all intents and purposes, centrally weighted where the shape of the sidecut and the flex of the ski will determin the arc of the carve. That's the first variable that's difficult to eliminate, we are always adjusting our edge pressure. I think it's safe to assume that a pair of skis are engineered to behave in an identical manner so if they are pressured differently they will bend differently . . . more pressure = more bend . . . OOOOO FOOOK shorter radius Shocked Shocked sooo..... our uphill or inside ski is going continue on it's lazy path to oblivion and pass over the hard working downhill ski . . . . Ummm YES! We do that . . . with the concomitant yard sale that ensues along with the chorus of pisstaking by the ubiquitous audience.

Those that don't spread their worldly goods and body fluids across the slope have managed to avoid this by ensuring that the inner or uphill ski stays inside the track of the lower ski . . . well we can't do this by applying more pressure, we'll just 'wash out'. What we do is shove the tip of the inner ski ahead of the downhill ski . . . the "Tip Lead" of the title . . . This makes the inner ski turn earlier than the lower ski, staying inside the outer track. The more force into the outer ski, the further ahead the inner ski has to be to stay inside that outer track. he stiffer the ski, the further forward it needs to be or the harder you need to pressure it to keep that tip from crossing over the outer

Eliminating "Inner Tip Lead" requires you to make sure that you pressure the tip of the inner ski to make it turn inside the track of your lower ski. . . this is made more difficult as the slope becomes steeper and your stance is forced to be wider. Mathematically it creates a compound curve in the inside ski that ensures it has a shorter radius than the simpler weighted arc of the lower ski. What is interesting is that the two radii have different centers of rotation (we're staying two dimensional here)

In an ideal World where a skier is being propelled at a constant velocity across a flat field of snow it will be possible to keep the feet parallel and describe what appears to be matching, equidistant, parallel tracks . . .but that's not skiing down a hill.

On that hill, if we manage to negotiate a carve, then pass through a transition into an opposite carve what happens is that we create two sinusoidal tracks that are out of phase with each other. they can be described as parallel but the width is variable as defined by our skills. The uphill ski will always have a shorter turn radius than the lower, but the center of the two radii will only ever be the same when their paths cross in the turn transition.

When skiing, the only time that legs can be described as having equal influence is when they are dangling off a chairlift.


Last edited by Otherwise you'll just go on seeing the one name: on Sat 8-11-08 10:51; edited 1 time in total
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 Poster: A snowHead
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Masque, I've only come into this on this page, can't be done with reading 22 pages, so please excuse me.
2 Skis carving with parallel tracks hip width apart, surely the radius of the arcs would be identical, because the centre of the radius of each arc is in a different place, i.e. the Hips.
So 2 identical arcs with 2 different centre points, or is my thinking failed? Puzzled
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Spyderman, You are correct.

(certainly in the case of clean arc to arc park and ride skiing).

I cannot imagine for a moment why people think that two identical skis with the same sidecut should produce different radii.

I suppose it's much like people believing, and chefs perpetuating, that you can "seal the meat" by frying it at a high temperature.
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Spyderman, you're getting there. A ski will describe a sinusoid path down a hill. Two skis, unless on the same track or not in a rigid 2 dimensional mechanical srtucture . . . and that's the last thing your groin can be sdescribed as . . . will always follow differing tracks. Their centers of rotation will always be different, but in combination with the path of your Centre of Mass, will stay in dynamic balance as you fly down the hill . . . or not, as the stains in your pants demonstrate Twisted Evil
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veeeight wrote:
Spyderman, You are correct.


Thanks, saved me 22 pages of reading then Very Happy
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veeeight wrote:
Spyderman, You are correct.

(certainly in the case of clean arc to arc park and ride skiing).

I cannot imagine for a moment why people think that two identical skis with the same sidecut should produce different radii.

I suppose it's much like people believing, and chefs perpetuating, that you can "seal the meat" by frying it at a high temperature.


You do realise that you're arguing against yourself do you?. I also take a little offence that you're you're using a completely 'out of context' statement . . . and one that I happen to agree with you . . . to dismiss my post.

I've already said that a pair of skis are designed behave as matched pairs and as we all agree we don't bend the inner ski in the same manner or with the same weighting as the outer. That doesn't mean that they have to have the same turn radius.

A ski's flex is NOT linear . . the manufactures make great store of this . . . so why should you try to explain yourself by using a description of a physical characteristic that is contrary to design criteria?
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Masque, I'm not arguing with myself, I just wanted clarification as to if the idea of what I've got in my head as to what's happening as regards to the arcs of the skis is correct or not. veeeight, and yourself
Quote:
Spyderman, you're getting there.
confirms to me that my understanding is correct. The complex physics and mathematics behind it, quite honestly are a bit beyond me.
I'm certainly not dismissing your post and in fact it was reading it that prompted me to post here in the first place.
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veeeight wrote:
Spyderman, You are correct.

(certainly in the case of clean arc to arc park and ride skiing).

I cannot imagine for a moment why people think that two identical skis with the same sidecut should produce different radii.

I suppose it's much like people believing, and chefs perpetuating, that you can "seal the meat" by frying it at a high temperature.


Once again: two identical arcs, circles or radii or what ever u want to call them, cannot exist in parallel, even in 3D. Consider a railway track going through a turn. Both rails have different centres and remain parallel, but their arcs are NOT identical.
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Masque, in an earlier post you said:

Quote:
they are both describing different arcs of concentric circles



Now you are appearing to agree with me that the arcs are identical:

Quote:
pair of skis are designed behave as matched pairs



Which side of the fence are you coming down on?
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PJSki, I have already agreed with that statement on page 10 and 20.

But I am still puzzled as to why you hold to the belief that ski tracks on the snow are parallel, describe concentric circles/arcs, and are not identical?
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Spyderman, You muppet! I was addressing Vegetable Juice, rolling eyes

Two skis attached to a single skier have sinusoidal tracks that intersect via vector forces with a common path defined by the CoM of the individual. All the bollux about "parallel" is just that . . .bollux

All twenty odd pages of this crap boil down to trying to explain why people manage to stay in balance over their skis . . . regrettably a number of them can't even understand why sh*t rolls downhill rolling eyes

veeeight, I was trying to simplify it for the masses

As for fences, Even you must understand that a fence can be bent more in one place than the other. Two skis with the same forces applied in the same manner will, hopefully, perform identically . . . that's not skiing. We use each ski as a pair of independent forces to balance our CoM inertia . . . this is why you are able to stand up. . . and why we bend skis in different manners depending in which foot they're attached to.


.... It's called "inner tip lead" It's why it occurs and why a nuance of technique and application of force can make a difference to body position and the arc that the CoM will traverse.
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Awesome, awesome the whole lot of it.

Masque, Well done mate.

veeeight, Groundhog day.
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veeeight wrote:
PJSki, I have already agreed with that statement on page 10 and 20.

But I am still puzzled as to why you hold to the belief that ski tracks on the snow are parallel, describe concentric circles/arcs, and are not identical?


A pair of skis tracking around a curve cannot be doing so in parallel and at the same time be tracking identical aces.
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Masque, I am still no clearer if you support if ski tracks are identical or parallel.

However - and clearly a topic for a new thread - you understanding of inner tip lead and interaction with this topic - is very very misunderstood. There are several threads on this board about tip lead, and the only thing I will say here is that tip lead is consequence of many things, and not a deliberate move.


Last edited by So if you're just off somewhere snowy come back and post a snow report of your own and we'll all love you very much on Sat 8-11-08 12:12; edited 1 time in total
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PJSki, so, are ski tracks (left by clean arc to arc park and ride skiing) identical or parallel in your view?

I feel like Jeremy Paxman asking the same question to many people many times?

Yet no one will answer this question directly!
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szk, I await for this thread to be moved to Gold!
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veeeight, Masque, PJSki, Just been sitting here thinking....dangerous I know.
If you put both skis on edge to carve them, the inside ski carves it's track, the outside ski has more pressure on it, therefore carving a tighter radius. If it didn't carve a tighter radius it would move away from the inside ski.
Have I been drinking too much? Confused Confused Confused
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Spyderman, you are on the right lines. If you understand this specific post, you will be doing 300% better than many on here.

In a park and ride skier, when both skis are put on their edges at the same time by the same amount (simultaneous movements of both legs, feet, skis, parallel shins) - the tracks left are two identical tracks, of the same radius.

These tracks will have the apperance of being narrower in the transition, and wider at the apex.

(there are other reasons why racers may choose to deliberately narrow their feet at transition).

However.

If you are a dynamic skier, with some ability to load a ski and bend it, yes, the outside ski will indeed track a tighter radius at the apex, and in many cases, will negate/cancel the apperance of the wider track at the apex, giving the appearance/illusion of "parallel" tracks left in the snow around the apex (demonstrated time and time and time again with repeated experiments with many racers last season - the tracks around the apex end up the same distance apart).

(the other less elegant way to bodge this is to have an A frame - the outside ski has a higher edge angle than the inner ski, so the outside ski will track a tighter radius).

One of the disagreements around here is that some people seem to think that the inside ski must track a smaller radius to conform to the laws of parallel arcs/circles. - What do you think will happen to their skiing if they try to make the inside ski bend more than their outside ski?
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veeeight, as a simple result of forces induced by or forced on the individual and the terrain of the hill, a pair of ski tracks are neither "identical or parallel". They may, within our limited visual perception look that way but we are all aware of our skis being knocked about by the conditions. It's the simple fact that there is a ski attached to each foot and in any manoeuvre . . . including a carved turn . . . the two feet are performing different tasks at any one time. Having a ski on each foot only accentuates the difference. A lack of understanding about how a tool (ski) performs (and let's not forget the boot and body attached to it) while stressed does not allow for a generic and grossly fraudulent description of the paths the skis take.

I would welcome a discussion on how and why we can or need to control our our position over our skis but that's not going to be constructive if one of the protagonists cannot understand that each ski in a pair is subject to differing forces and will never be "identical or Parallel". it is our learning and gained skills of control that makes them appear that way to the gullible.

As for not understanding "Inner tip Lead" . . . there's a bait to my fish . . .

I know its bio-mechanical function
I understand its cause in regard to speed and inclination (not the mental form)
I certainly have experienced the factors of equipment that determines the ability of the individual to control the degree of tip lead
I can actually draw the vector/geometric formulae for a conjoined pair of arcs . . . though I'll need help to do it in it's 4 dimension reality
Lastly, I'm certainly not dumb enough to think that a ski is a dynamically inert object that has a fixed and rigid response to any user input.

I'll certainly agree "that tip lead is (a) consequence of many things" and I'm pretty certain that is what I said on the first page of this thread . . . however, controled 'tip lead' is a deliberate move required to keep a carve/turn to the desired track
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Spyderman wrote:
because the centre of the radius of each arc is in a different place, i.e. the Hips.

Untrue. The hips have very little to do with the "centre of radius" (actually the correct term is "centre of rotation", but I know what you mean). Hence that is no argument to support your conclusion. If you were stationary and just dragging your skis around your legs then that would apply, but I take it you see how ludicrous that is. This is also a simple concept V8 seems to have trouble with. (And if you don't want to just take my word for it, Martin Bell is of the same view, back on p5).

veeeight wrote:
And I quote:
Quote:
Thus, an outside ski carves an arc of a tighter radius than the inside one

Be careful where you quote from, particularly when being selective, or it might bite you in the bum, as in this case. The very next sentence is:
Quote:
This ultimately produces converging tracks.
and the picture immediately following that line shows Gurshman with skis converging markedly. And please don't misrepresent me - I've lost count the number of times I've said that any analysis I and SSBob made based on circles is purely for ease of explanation (it's actually you who keeps on dragging it back to circular analyses), but the conclusions are general. And I've several times pointed out the problems (tracks crossing, outside tip lead etc) that would be required if you want the tracks to be identical.

Right from p5, I have been saying that there is no problem with the outer ski tracking a tighter radius, for part of the turn - but that the tracks are not then parallel, there will be convergence and divergence, and there will be other parts of the turn where the inner ski is then turning tighter - statements backed up by FastMan and PhysicsMan. Throughout that article Gurshman (BTW I notice V8 can't even get his name right) has also been talking about tracks that are neither parallel nor identical: some have tracks that get deeper or wider, in some the inner ski is lifted completely off the snow (and so any turn there is clearly purely foot rotation). Most of the montages show widely varying track separations.

But if you want a railroad turn (in which by definition the tracks are parallel) then you can do them - but in which case they are not identical and the inner ski has a tighter radius than the outer.
Martin Bell, back on p6 wrote:
Well, we all know parallel railroad turns are possible in the real world. Here are some:
http://easylink.playstream.com/daignault/carving2arailroad.wmv
So what is actually happening?
The radius of the inside ski is probably being made tighter than that of the outside ski, through added shovel flex, caused by extra shin/cuff pressure and snow compression. (On an infinitely hard surface, like in PM's model, this would not be possible).
There is also probably some minute diverging and converging of the skis, as alluded to by SS Bob.
There is occasionally slightly more edge angle on the inside shin, causing a fractionally "bow-legged" stance. (Mentioned by david@mediacopy although he doesn't "feel" it in his skiing.) This is so small as to be almost imperceptible, but remember these are very shallow arcs, tiny fractions of the full circles, so the difference does not need to be very large.

All in all, good reminders that railroad turns are an artificial drill that has little to do with the way skis actually work on the snow. IMO it's more a way of getting pupils to show body awareness and learn to focus more on the inside leg.


Last edited by You need to Login to know who's really who. on Sat 8-11-08 13:16; edited 1 time in total
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veeeight wrote:
One of the disagreements around here is that some people seem to think that the inside ski must track a smaller radius to conform to the laws of parallel arcs/circles. - What do you think will happen to their skiing if they try to make the inside ski bend more than their outside ski?


This is the crux which the paper and math explanations don't seem to explain. If the inner ski is describing a smaller radius, what is the mechanism the skier is using to do this ? In real life the inner ski is not pressured or tilting more then the outside one Puzzled
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david@mediacopy, it isn't (describing a smaller radius). Thus there is no mechanism which the skier is using (unless he wants to produce a diverging inner ski).

It amazes me that some people still cling onto this concept.
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Spyderman, If I get the time I will try to do a video, but in the meantime and as I said above, the downhill ski is pressured more and is bent in a fairly stable arc through its stiff centre. The uphill ski has been pushed forward by your body angle to the slope of the hill. Lots of tip lead means that you are dancing the tip along the slope with foot turning to keep the uphill tip inside the track of the lower ski. Nearly all your weight/pressure is in the lower ski and you are almost lifting (and some do) the inside ski to stop the tips crossing. If you bring the uphill ski back toward the downhill track you will ergonomically apply pressure to the inner tip forcing it to bend at a tighter angleupward to stay inside the outer track. This creates a compound curve in the ski that has its centre of turn slightly shorter and lower on the hill than the downhill ski . . making its radius shorter even though the ski does not appear to be bent as much. You will also find that foot pressure has become more equal and as such the arc of the lower ski has been reduced making its radius of turn longer.

A pair of skis in motion will NEVER be parallel or identical, they are ONLY two parts of a mechanical whole and always have to be controled individually to make the sum of their actions complete a single result.
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GrahamN, I have no problem with the next sentence of producing converging tracks. Again, you are being selective in what I believe in, and don't. I have already stated many times, the most recently in my reply to Spyderman, that identical tracks from a clean arc to arc skier will produce narrow tracks at and heading towards the transition.

And - if - as a skier - you cannot produce clean arcs without recourse to fudging, then I put it respectfully to you that you should keep practising.

As you seem to be professing to be much cleverer than me, I am surprised that you cannot see how we can have identical ski tracks without the paths converging in real life. You are being constrained by your thinking in your last sentence, when you have to return to the belief that the inner ski has to be a smaller radius than the outside ski.

It's a poor show and a sign of desperation when you have to resort to picking me up on my typos. Try not to make it personal and keep it civil.
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veeeight, p5, Apr16 wrote:
If you are scissoring (defn: diverging inside ski or diverging outside ski), you are NOT carving clean arcs. Mutually exclusive. End of


veeeight, ibid wrote:
Quote:
So, the inside ski neither converges nor diverges but stays the same distance apart throughout the turn

That's why it's called a parallel turn.


But then we had a glimmer of light
veeeight, p8, Apr 17 wrote:
And this could well explain why good skiers, that hold a constant ski width, will often have slightly narrower tracks at the transistion than apex (as both skis have the same radius).

Perhaps parallel skiing is a misnomer wink

with which we all agreed (allowing for some termonological inexactitude), until
veeeight, ibid wrote:
eg: I'll ski some perfectly identical AND parallel RR ski tracks, with both skis at the same/matching edge angles at all times, and with no rotary fudging (and so will the rest of the crowd in the bar, who are, by now, quite annoyed at being told that what they are doing is impossible).


And then we had
Martin Bell, p14 wrote:
veeeight wrote:
Scissoring and Diverging are NOT part of carving/skiing,


How can you say that, when the graph which you yourself put up, clearly shows the skis getting wider (diverging) into the turns and getting narrower (converging) out of the turns????? (None are as blind as those who will not see... - but this is "doublethink" worthy of 1984.)
There were then various diversionary tactics about diverging skis not tracks - the only way for a ski to be diverging but the track to be parallel (or vice versa) is for the ski to be skidding.

Your reply to Spyderman above is interesting in that it's thefirst time (that I can find anyway) that you've agreed that identical tracks will diverge at the apex, in recreational skiing - except for that post on p8, and something similar on p13 (and note both qualified as being something reserved for good or fantastic skiers). These were points that Sideshow-bob, laundryman and I were making to you back on pages 7-9 and beyond. The only times you allowed for convergence/divergence was calling it a "mistake" by Grandi (p6), and all the other WC skiers Martin pulled up for demonstration. You've allowed for such changes in competition skiing, but only as examples of loss of form in the interests of speed. Which rather begs the question of why the form is so desirable if it results in lower performance skiing Wink.

Whether or not I am more clever than you is not really relevant. I have very little doubt that you'd be able to run rings around me on skis, but we're not complete duffers either. What is clear though is that I (and many others here) have a much better grasp of maths, physics and mechanics. I'm not entirely sure whether the fact that we can't get over to you where you're going wrong says more about you or us.

I reiterate, the argument from our side has never been that one can't ski parallel, or identical, but that a) one can't do both simultaneously and b) if they're parallel (i.e. making railroad tracks) then the skis are not being treated identically. And for the umpteenth time, there has been no argument that if you relax the requirement to be parallel then radii of inside track can be greater than that of outside for some part of the turn - but it is true that the overall radius of the inside track is tighter than that of the outside, and the tracks diverge/converge.

BTW: the photo here may be of interest. Guess what - inside ski is at slightly more acute angle than outside! The inside shin is not, but the canting on my boots was a bit out at that time. The important point there (and related to points made way back in the thread) is that what is important is what's happening at the skis - exactly what angles etc the rest of your body take up are of much less importance; if you are sensitive to waht your skis are doing you just do what is required to achieve the desired effect. And to expand on that point, when I changed my boot canting a couple of months after that photo, the poisitions of my legs adjusted to accommodate it, and it felt odd for a few hours, but then I got used to the new positions and really don't feel any major anatomical differences now. I guess there'll be all sorts of other faults, but that's probably for another thread.


Picture courtesy of RacerReady.
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veeeight wrote:
identical tracks from a clean arc to arc skier will produce narrow tracks at and heading towards the transition.


Great! At last, we are all in agreement, that the tracks cannot be simultaneously identical and parallel (meaning equidistant).

So the logical conclusion, is that divergence and convergence are a frequent and necessary part of top-level skiing.

As I mentioned earlier, these are not "mistakes" or "untidy skiing", they are demonstrated time and time again at the highest level:


http://www.ronlemaster.com/images/2006-2007-B/slides/kelley-aspen-2006-gs.html (frame eight)
http://www.ronlemaster.com/images/2006-2007-B/slides/ligety-aare-2006-gs-1.html (frames 2 and 13)
http://www.ronlemaster.com/images/2006-2007-B/slides/matt-bc-2006-sl-1.html (frame 3)
http://www.ronlemaster.com/images/2006-2007-B/slides/paerson-aare-2006-sl-2.html (frame 5)
http://www.ronlemaster.com/images/2006-2007-B/slides/raich-aare-2006-gs-2.html (frame 7)
http://www.ronlemaster.com/images/2006-2007-B/slides/zettel-aspen-2006-gs-2A.html (frames 5 and eight)
http://www.ronlemaster.com/images/2006-2007/slides/hosp-aspen-2006-sl-2.html (frame 1)
http://www.ronlemaster.com/images/2006-2007/slides/poutiainen-aspen-2006-gs-1A.html (frame 3)
http://www.ronlemaster.com/images/2006-2007/slides/schld-aspen-2006-sl-2.html (frame 5)
http://www.ronlemaster.com/images/2006-2007/slides/zettel-aspen-2006-gs-1.html (frames 5 and 11)
http://www.ronlemaster.com/images/2006-2007/slides/schlopy-bc-2006-gs-1.html (frames 8 and 9)
http://www.ronlemaster.com/images/2005-2006/slides/ligety-bc-2005-sl-1a-flat.html (frame 4)
http://www.ronlemaster.com/images/2005-2006/slides/paerson-aare-2006-sl-2-web.html (frame 5)
http://www.ronlemaster.com/images/2005-2006/slides/rahlves-bc-2005-gs-2-web.html (frame 9)
http://www.ronlemaster.com/images/2005-2006/slides/zettel-aspen-2005-sl-2-web.html (frame 4)

Not to mention converging skis:
http://www.ronlemaster.com/images/2006-2007-B/slides/stiegler-aare-2006-sl-2.html (frame 5)

And how about both:
http://www.ronlemaster.com/images/2006-2007/slides/schild-aare-2006-sl-2.html (frames 5 and 6)

So the next question is: why are instructors and coaches not talking about divergence and convergence? Gurshman doesn't mention it in his article, even though he clearly demonstrates it in his photo sequence.

Perhaps they are trying to adapt the real world to fit some neat and pretty theoretical concept.

But I repeat: if the arcs are identical, there WILL be divergence and convergence.

veeeight wrote:
If you are a dynamic skier, with some ability to load a ski and bend it, yes, the outside ski will indeed track a tighter radius at the apex


If that happens, there will be even more divergence and convergence.

veeeight wrote:
(the other less elegant way to bodge this is to have an A frame


This demonstrates the source of much of this disagreement: different frames of reference and education. We must have some sympathy for Veeeight - he is a ski instructor so he has been conditioned to think about concepts such as "elegance". I am a ski racer (as are some others in this discussion) - we don't care about elegance, only about what actually happens on the snow in order to produce the fastest time from top to bottom.

The world's best racers don't care about "elegance" either:
http://news.dipag.it/pictures/lowres/20071028/Bode-Miller-in-action-0000016716.jpg
http://cache.daylife.com/imageserve/07WF5zM7jacPb/610x.jpg
http://www.usskiteam.com/public/uploads/news/120807_35329_2_3186_news.jpg
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