 Poster: A snowHead
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comprex, well the Austrian's got away with it for a season 
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Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
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CEM, Thanks for your colourful explanation. Though your last sentence would do great justice to the french policeman in Hallo Hallo 
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Well, the person's real but it's just a made up name, see?
Well, the person's real but it's just a made up name, see?
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You need to Login to know who's really who.
You need to Login to know who's really who.
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Anyway, snowHeads is much more fun if you do.
Anyway, snowHeads is much more fun if you do.
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If you use disney plates, can you still ride goofy?
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You'll need to Register first of course.
You'll need to Register first of course.
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CEM, I'm waiting for those too! Think I might go for the RD, my RS120s are deffo too soft. But as it was we already had to stretch the shell, so with the RD it'll be a bigger stretch.... 
Yeah they are Solly plates, just had to grind the little tag off.
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You'll get to see more forums and be part of the best ski club on the net.
You'll get to see more forums and be part of the best ski club on the net.
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You've spoken on here about the differences in the boot as a new liner compresses - how many hours skiing will this take. I've worn my boots for about 5-6hrs a day for 7-8 days - will mine be bedded in yet? About half way through the week my instructor had me tighten my boots up - more around the top clips than the ones across the lower part of the foot - I guess this was due to the compression of the liner? - I do remember the skiing being instantly easier after he had tightened them.
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Megamum, the liner will continue to break in or should i say wear out, it will carry on compressing throughout its life, after another couple of weeks you will keep clipping the boot tighter and tighter...sounds like there may be a little too much volume in the shell...difficult to say without seeing it but if you are asking the question and you are tightening up boots constantly it sounds as if it could be 
we need to get this back on the topic of edging..... technique, boot fit, balance but all as relates to edging
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snowHeads are a friendly bunch.
snowHeads are a friendly bunch.
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CEM, OK, so yes I'm in danger of hijacking the thread, but I've read a lot of this and just gone back and checked and my observation that the skiing was easier is related to a lot of this - once the boots were fitted more snuggly around the upper areas the skis were quicker to go in the direction that the legs intended - almost as though they were more responsive - I could actually feel the skis digging their edges into the snow - this was quite an enlightening moment.
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And love to help out and answer questions and of course, read each other's snow reports.
And love to help out and answer questions and of course, read each other's snow reports.
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CEM, Just put Nordica ones on, the fit every shell (as almost every plug shell is now been birthed by the Doberman.), but don't come cut so red dust everywhere.
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You know it makes sense.
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So, CEM - have you got a router and table set up already then 
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Otherwise you'll just go on seeing the one name:
Otherwise you'll just go on seeing the one name:
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CEM, I can source Nordica for you, drop me a PM with quantities and heights. We're not doing much than 3mm although it's still fun wacking on some 11mm and shreading plastic everywhere.
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Poster: A snowHead
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Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
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Megamum, It sounds as though your boots were actually quite loose around the cuffs before you tightened them, if you got such a dramatic response. It's really good that you felt the edges, that's a big step forward. The point is that your boots need to be tight enough (as an intermediate) to allow your foot movement to affect the ski, but the tightness we were talking about before is very tight, and that isn't necessarily the best thing as it resticts your ankle/foot/lower leg movement. Of course, I'm not a bootfitter, but as a ski teacher that's my take on it. If your boots are too loose (until you're quite practised) you won't be able to edge properly at all.
There - back on track! 
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Well, the person's real but it's just a made up name, see?
Well, the person's real but it's just a made up name, see?
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Megamum has actually hit upon a key point of the mechanics of edge control. In the end, it doesn't really matter how much your foot can "roll" within the boot. Apart from the boot's lateral flex, it is the amount of actual lateral movement at the cuff that determines how much your ski's edge angle can physically change due to ankle-based movements.
The ultimate logical extension of this principle: the NAVA system! 
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You need to Login to know who's really who.
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easiski, Martin Bell, Both your observations on the change that I noticed make a great deal of sense. I think the boots were quite loose at the cuff - it was the first week that they were used and to begin with I could only feel comfortable with the catch on the widest setting around my lower calf. The day the instructor tightened them for me I'm sure he tightened them at least 2 and maybe 3 catches tighter than they had been. I remember thinking crikey! but despite my expectation that they would be uncomfortable after a while and start to cut off my circulatio they remained nice and comfy just snugger than I had been skiing in before. Of course it made an instant difference - like the difference between putting a stake into a hole that is too big and having it wobble around, and filling in some earth and making the fit tighter. Once tightened when I made a correct movement with the lower part of my legs to put the ski on its edge it came with me rather than the movement being lost in the slackness of the boot cuff. That said I think there is a limit as to how tight would be useful and as easiski, points out very tight may result in the loss of other functions of the foot. However, I don't think I'm skilled enough yet to comment on these angles, only that I found that boot cuff tightness seemed to make at least some contribution to the process at my level (which I'm sure is not intermediate yet!)
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Anyway, snowHeads is much more fun if you do.
Anyway, snowHeads is much more fun if you do.
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Megamum, think firm handshake, not the wimpy wet kind, a really good 'welcome to the board' type handshake
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You'll need to Register first of course.
You'll need to Register first of course.
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And tomorrow..... the physics behind the advantages of getting the ankle closer to the centre of the turn.....
(I haven't got time to scan in the diagrams now)
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veeeight, Can't wait 
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veeeight, EPIC ALERT - EPIC ALERT - EPIC ALERT! 
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You'll get to see more forums and be part of the best ski club on the net.
You'll get to see more forums and be part of the best ski club on the net.
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I've meant to put my closing thoughts on this topic sooner, but hadn't the time to get pictures scanned in etc. - but anyway - I have now!
I do acknowledge that there are more than one school of thought on this, for some, they will prefer to ensure that cuff (and therefore knee angulation) is doing the work, and that the ankle rolling is merely a mental trigger.
Most importantly - we should all agree that the foot must be allowed to work as a foot inside the boot, and not be encased inside a block of concrete.
This "ankle rolling" this is not new. Georges Joubert refers to it in his "Skiing - An Art A Technique" book, and talks about "pressure on the malleolus", and the "muscular effort required by the foor inside the boot" to ensure good hold on ice.
Warren Witherell in "The Athletic Skier" talks about the ankle joint in terms of efficiency - "If you need a few degress of edge, roll your ankle. If more edge is needed, knee angulation is quicker than hip angulation - but it's not as strong. When G forces are high, hip angulation or full body inclination is needed. Quiet upper-body movement allows the best control of the ski through lower body movement. At all times do as little work as possible to achieve a desired result."
In "How the Racers Ski" (Warren Witherell) - In describing what he see's the ski doing in the snow, he describes "Most pressure and edge changes should be instituted primarily by ankle and knee movement".
These books and authors aren't some half baked newfangled fly by night things, these are well respected titles and authors, and now for the third, Ron LeMaster.
The following is shamelessly ripped from Ron's "The Skier's Edge" - so those that already have a copy can sing-a-long at home!
Have you thought about how an ice skate holds? Skates are not nearly as stiff and powerful as ski boots. The ice in any rink is as hard as the worst boiler-plate a skier is ever likely to see, yet a casual skater can describe clean arcs on a rink, while good skiers often struggle to make good turns on snow that is not nearly as hard.
The difference lies in the relative locations of the ankle and weight bearing edge. The blade of an ice skate is directly underneath the entre of the skater's ankle, so when the skate is on edge, the force that the ice exerts on the blade passes directly through the centre of the skaters ankle.
In contrast, the edges of a ski are offset from the centre os the skiers ankle.
In the diagram above, the force S from the snow acts along a line that passes outside the skier's ankle. The distance L from that line to the skier's ankle creates a lever through which S exerts a torque T on the ankle. T seeks to twist the skier's ankle, flattening the ski on the snow, making it slip.
The longer L is, the greater T will be, which is why fat skis are harder to get on and maintain edge.
The key to holding then, is to make the the situation more like a skate - to get the ankle as close as possible to the line along which the force from the snow acts.
The closer the centre of the skier's ankle is to the line S, the smaller the torque on the ankle, the better the hold/grip of the ski on the snow. As well as explaining why a narrower ski under foot holds better, this also explains why skis hold better in soft snow. As the ski is driven further into the snow, the snow's reaction force moves closer to the centre line of the ski, making T smaller.
So: In order to reduce L and T, we can do 3 things:
1. Ski narrower skis (so that it behaves more like a skate) (FIS Limits apply)
2. Use risers, lifters and plates to reduce L (and therefore T) (FIS limits apply)
3. Move, or roll the ankle to the inside of the turn, so that the centre of the ankle is closer to S
The following diagrams shows the effect of rolling the ankle into the turn, plus knee angulation, making the torque T smaller
The following diagram shows the effect of adding lifters/risers/plates to achive moving the centre of the ankle closer to S
As they say, the proof of the pudding etc. Find a nice icy pitch, and actively try and hold an edge on your skis, with and without activating your ankle(s). In short, anything we can do to reduce T the torque on the ankle (which is constantly trying to flatten our ski) will lead to increased edge hold.
Happy Skiing!
Last edited by You'll get to see more forums and be part of the best ski club on the net. on Thu 7-06-07 21:44; edited 1 time in total
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veeeight, while I appreciate your "physics" (sounds more like engineering to me, but then I'm only an ex-physicist) ....
Whether or not I can do anything to my ankle, when I'm happiest in a boot my shin move with the boot. Very little give and take. It works fine for me. I don't think (although I may be unknowingly) I'm actively using my ankle at all. I don't think I can see how to.
And I can edge quite fine thanks.
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snowHeads are a friendly bunch.
snowHeads are a friendly bunch.
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And love to help out and answer questions and of course, read each other's snow reports.
And love to help out and answer questions and of course, read each other's snow reports.
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comprex, Have you noticed that a similar debate is raging over the pond at the "other place"? A tale of 3 turns, post #326.
The following are not my words, I haven't contributed in that thread, there are more armchair quarterbacks there than there are here at snowHeads 
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I would be very worried if I was coached into using my ankles to attempt to tip my skis that are locked into a stiff pair of boots, when I have a very powerful pair of thighs that can do the bulk of the work, the bulk of the time. with incredible accuracy. |
Grasshoppa, you have much to learn.
Your thighs are incredibly accurate? WRONG. Your hands and feet are. Your legs are powerful, not accurate.
Your feet are "locked" into your boot? Fix that, its not a good thing.
You can evert your ankle inside the boot in fact, and that will result in your ankle pushing against the sidewall of the boot. This shift of balance will create a kinetic chain, chain reaction which results in body parts up your leg and eventually to your hip all moving in that direction.. |
All this ties in with Euan's EoSB homework, "Hips for power, knees for strengh, ankles for accuracy", which not many seem to have bothered with
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I've thought about it, and thanks to your input in this thread I've got a much better idea of what is being said. But I'm still trying to get my head around it because it seems so alien to all my skiing instincts! I'm hoping to catch up with Euan over the summer so will pick his brains a bit more on this.
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You know it makes sense.
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| David Murdoch wrote: |
| I don't think I can see how to. |
Imagine a dash butter churn, bottom to cover height H. The plunger is a tight fit in the churn, the cover is tightly fitted to the plunger handle. Now imagine the plunger handle is hinged about H/3 from the plunger itself.
Can you tilt the plunger handle without tilting the churn?
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Otherwise you'll just go on seeing the one name:
Otherwise you'll just go on seeing the one name:
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veeeight, This is my first foray onto this thread and I find your diagrams fascinating.
I have a couple of queries though.
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Have you thought about how an ice skate holds? Skates are not nearly as stiff and powerful as ski boots. The ice in any rink is as hard as the worst boiler-plate a skier is ever likely to see, yet a casual skater can describe clean arcs on a rink, while good skiers often struggle to make good turns on snow that is not nearly as hard.
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I used to skate, although spent most of the time on my butt. I would have thought the main reason for a skate gripping on ice, is to do with the loading on the edge. A skate is only say 40cm long and a ski say 170cm long, therefore 4 times more load to make the skate cut into the ice. 
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The closer the centre of the skier's ankle is to the line S, the smaller the torque on the ankle, the better the hold/grip of the ski on the snow. As well as explaining why a narrower ski under foot holds better, this also explains why skis hold better in soft snow. As the ski is driven further into the snow, the snow's reaction force moves closer to the centre line of the ski, making T smaller.
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I always thought that the main reason a wider ski had less edge grip than a narrow one of similar construction, was more to do with it's torsional rigidity diminishing as width increased, therefore allowing the ski to twist under load, reducing edge angle and pressure.
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Poster: A snowHead
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| Spyderman wrote: |
veeeight, This is my first foray onto this thread and I find your diagrams fascinating.
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Have you not read Ron LeMaster's book The Skier's Edge. It's brilliant; essential reading.
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Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
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Spyderman, yes, the higher force on a smaller area exerts a larger pressure, so length of blade is a factor, not necessarily *the* factor.
Anytime there is a torque on the ankle (ie: on skis) - that torque will always try to flatten the ski - away from the critical edge angle that is making the ski grip. Racers will always try to decrease this torque by the methods outlined above (narrower skis, higher lifters, rolling ankles) - which is why FIS have placed limits on these.
As to the torsional stiffness, yes you are correct, but this is only 1 factor that is commonly seen in the marketplace, in the sense that in general, wider skis are torsionally less stiff that narrower skis. However if you were to obtain a fat ski with identical torsional flex as a narrow ski, you'd still be fighting T, the torque placed on the ankle, that will constantly be trying to flatten the ski. So, although my iM88's are reasonably torsionally stiff - I still have to work harder in getting then up on edge, and holding them there gripping, than when compared with my iSL RD slaloms on an icy pitch.
Bear in mind that the words and diagrams above are not mine, but those of the *guru* Ron LeMaster. (I've edited my post above, and put the book references in bold - essential bookshelf material for any ski geek. But the colour slides are from a presentation Ron gave us a couple of years ago).
Last edited by Obviously A snowHead isn't a real person on Thu 7-06-07 22:12; edited 2 times in total
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Well, the person's real but it's just a made up name, see?
Well, the person's real but it's just a made up name, see?
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rob@rar, veeeight, Thanks guys, looks like I need to get hold of some bedtime reading.
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You need to Login to know who's really who.
You need to Login to know who's really who.
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Spyderman, if you can wait 2 weeks, I'll lend you my copy.
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Anyway, snowHeads is much more fun if you do.
Anyway, snowHeads is much more fun if you do.
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Careful now, Foxy. You'll have SZK moaning that we are propogating Disney stuff!
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You'll need to Register first of course.
You'll need to Register first of course.
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veeeight, it Disney matter what he thinks!
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Wear The Fox Hat, Thanks, I'll wait then. Ski test MK to BBQ should be enough time to read it. Unless it's War & Peace.
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Spyderman, I found it easy to read, but it appealed to my way of thinking. Except some of it was above my head.
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You'll get to see more forums and be part of the best ski club on the net.
You'll get to see more forums and be part of the best ski club on the net.
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I've had it 3 years now. And I still read it from time to time. And still glean additional information everytime I re-read it.
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| veeeight wrote: |
| I've had it 3 years now. And I still read it from time to time. And still glean additional information everytime I re-read it. |
Ditto. I have to confess that it mostly lives on my bedside table and I often read a section or two. I think I understand most of it now, even if I can't put that much into practice 
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FAQ
