 Poster: A snowHead
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Just to put my two pennorth in before this thread disappears up it's own backside, the length of the ski is one of many factors involved in the grip available, but is less relevant than its stiffness, both longitudinal and torsional. It doesn't matter how long the ski is if most of the edge is not in effective contact with the snow; the more it flexes the less this will be; the more it twists the less this will be. And of course the most significant factor is the edge angle that the skier is able to generate.
I skied this weekend on both my 170cm SL (14.5m) and 180cm GS (18.2m) race skis and was really focussing on differences I could feel. On the hardest-packed bits, of which, TBF, there weren't that many, the SLs had a very slight edge (no pun intended) over the GS ones when I was trying to ski in good control with short round grippy turns. Their shorter radius was not insignificant, I feel, and the fact that they're only about 40 ski days old, compared with perhaps 2-300 days for the GS, so they've probably lost a significant amount of their original stiffness.
Conversely the GS skis felt much better, much grippier, on long fast carvy runs, as you might expect. There's no way I could possibly say that either the longer or shorter ones were better for grip overall and I'm confident that the differences I found were much more due to their radius than their length.
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Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
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I know enough physics and more than enough about discussions on the internet to be fairly confident that at least some people here are arguing from physical principles that don’t apply or aren’t adequate to describe the problem. However, I don’t know enough physics to be certain which those people are!
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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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@Chaletbeauroc, that makes sense. In general, but,
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the more it flexes the less this will be; the more it twists the less this will be
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longitudinal stiffness isn't material. It's not stiff enough. It's the torsional stiffness that makes a difference.
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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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| tangowaggon wrote: |
Nope, quite the opposite when trying to get edge grip on ice, shorter edge gives more pressure per cm & more likely to penetrate the surface to get grip & prevent side slide, this is basic physics logic, experience with short vs long edge confirms this, rather like comparing the abilty to grip ice with the head of a nail vs the point, it also confirms that the longer edge is more stable at higher speeds. |
If a GS ski can be skied more quicker than a SL ski, the G Force will be greater when turning at that higher speed.
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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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@Old Fartbag, but centrifugal force doesn't act in to the snow?
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You'll need to Register first of course.
You'll need to Register first of course.
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| Old Fartbag wrote: |
| tangowaggon wrote: |
Nope, quite the opposite when trying to get edge grip on ice, shorter edge gives more force per cm & more likely to penetrate the surface to get grip & prevent side slide, this is basic physics logic, experience with short vs long edge confirms this, rather like comparing the abilty to grip ice with the head of a nail vs the point, it also confirms that the longer edge is more stable at higher speeds. |
If a GS ski can be skied more quicker than a SL ski, the G Force will be greater when turning at that higher speed. |
Nope again, the g or to give it its accurate name, centrifical force is dependant on the forward speed and the radius of the turn so the force will be similar for a large radius, fast turn and a short radius, slow turn.
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| tangowaggon wrote: |
| Old Fartbag wrote: |
| tangowaggon wrote: |
Nope, quite the opposite when trying to get edge grip on ice, shorter edge gives more force per cm & more likely to penetrate the surface to get grip & prevent side slide, this is basic physics logic, experience with short vs long edge confirms this, rather like comparing the abilty to grip ice with the head of a nail vs the point, it also confirms that the longer edge is more stable at higher speeds. |
If a GS ski can be skied more quicker than a SL ski, the G Force will be greater when turning at that higher speed. |
Nope again, the g or to give it its accurate name, centrifical force is dependant on the forward speed and the radius of the turn so the force will be similar for a large radius, fast turn and a short radius, slow turn. |
Hmm - not convinced that a fast GS turn doesn't generate more force than a slow SL turn - but my maths/physics/mechanics are not strong enough to prove it.
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| under a new name wrote: |
| @Old Fartbag, but centrifugal force doesn't act in to the snow? |
Doesn't it act on the ski to bend it? In other words, you are "heavier" as you go round the arc at speed. The extra force generated is counteracted by a good stacked position and then dissipated by allowing the knees to come up in the Invisible bump.
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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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@Old Fartbag, mv^2/r gives the force required to go around a bend of radius r at velocity v.
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| johnE wrote: |
| @Old Fartbag, mv^2/r gives the force required to go around a bend of radius r at velocity v. |
Great - So what is your assessment of the effect of Speed going round an arc? Am I talking bollox? - if so, it wouldn't be the first time. 
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FAQ
