what is the concept behind side-cut radii as it relates to racing....

[alpinegirl]

i had a ski racer ask what the typical radius of a snowboard is. i offered up that my beast (for me it is a beast at 173cm on our hills terrain) had a radius somewhere around 14, and that it was a GS sorta board (it's a volkl, i enjoy it immensely). he remarked that that was small and comparable to a slalom ski. blah blah blah, GS skiis were usually over 20. i neglected to ask him what length ski that would be on.

what range of radii (and length i suppose) are pro's racing on?

what is the idea behind ski's and their sidecut radii?

do skiis decamber significantly more, hence requiring a longer sidecut radii in order to achieve a similar arc to a snowboard with a shorter sidecut radius? although alpine boarders crank the snot out of their gear so i am dumbfounded....


also, i have no racing what-so-ever in my background so it all beats the snot out of me. so please feel free to inundate me with useful info. i'm procrastinating and prefer this sort of thing over IPM.

[Jack Michaud]

The Volkl 173 has an 11.7m radius. Pro snowboard racers are generally using boards in the vicinity of 185cm and 15m for GS. I don't know about slalom.

In skiing, these days, a 15m radius usually appears on skis around 170cm long. Part of this has to do with the fact that a ski 185cm long with a 15m radius would have ridiculously wide nose and tail. I don't know what ski racers are using.

[Phil]

Dianne Roffe was telling me the other day that on the circuit, they are using low 20's for GS.

[NMU Alpine Boarder]

Slalom skis are getting down to the 160ish range with 11M sidecuts.

[philfell]

The line that a snowboarder takes is different than a skiier. On skies your transition takes you uphill and to the outside. When you transition on a snowboard you move downhill and inside. Also ski G.S. courses are huge when compared to snowboard PGS courses. We usually run around 22 meters from stubby to stubby, and the max you can set acorrding to FIS rules is 25 meters. But it isn't uncommon to see ski G.S. courses up to 34 meters.

Typically for PGS racers have between 14 and 15 meter radius, and for PSL the have 8-10 meter raduis.

[mirror70]

Doesn't FIS also have minimum sidecut radii for downhill and superG? Maybe for GS, too?

[Baka Dasai]

Originally posted by philfell
On skis your transition takes you uphill and to the outside. When you transition on a snowboard you move downhill and inside.

Can you explain this further?

[philfell]

In a ski turn you use the inside edge of your outside ski. When you move from turn to turn, you move from outside ski to outside ski.

When you move from turn to turn on a snowboard you move from inside edge to a new inside edge.

Look at your arcs in the snow, when you have a good clean transition the start of your new arc is downhill and inside of the arc before it.

I hope this helped explain what I was trying to say better.

[Baka Dasai]

OK, I now get what you're saying, but I think it would only be relevant to the extent that the skier is able to change the width of their stance at different stages of the turn - wider in transition, and narrower when going around the gate. Making a step up the hill during transition, for example.

<img src="http://ronlemaster.com/images/2003-2004/slides/paerson-pc-gs-1-wm.jpg">
<img src="http://ronlemaster.com/images/2003-2004/slides/ertl-pc-gs-1-wm.jpg">

[philfell]

It also allows you to take a straight line on skies. And you need a tighter radius turn on a snowboard to match the track of the skiier.

In your pics look at where her edge release is from one turn then the edge set of the next turn. In order for a snowboarder to match these you need to make a tighter turn radius because of the way a snowboard transitions from edge to edge.

[alpinegirl]

so eh?? for the racing inept among us (that'd be me, i know)...

granted, i know that boards take a different path, but does that translate into there being no "straight" transitions (i am not expressing this well, sorry)? any straight lines??

is PGS pretty much the standard that people should have in mind when they train??

what happened to running events as "normal" GS and SL? i've heard that PGS is more exciting and blah blah blah.....

and yeah, skiing turn mechanics. do they necessitate the larger side-cut? or is it simply the course set-up. i know that a course's set-up helps determine the desirable side-cut and length and stuff like that. but yeah, skiis??

oh yeah, you guys have been great thus far. i am still very interested in whatever anyone knows. and yes, i do still hear the call to run away and leave this place...

[philfell]

PGS and PSL are the standard anymore. They don't really have any traditional two run format races anymore. Mainly because the Olympics are PGS and all the World Cups are parrell events. It doesn't do the riders any good to race a format that won't help them move up internationally.

When I said "you to take a straight line on skies" I meant realitive to a snowboard.

As far as skies having a longer radius than snowboards, the reason is a combinatioin of things. The line they can take relative to a snowboard, their courses tend to have more distance between turning pole to turning pole, and FIS has stricter rules for skies.

Since snowboarding has gone to PGS the sidecut radius of boards has gotten smaller, due to different course sets.

[bobdea]

likes to set up all sorts of whack rules for skiers regarding sidecut this became a issue in SL a few years back when some genius figured out that small skis with deep sidecut kicks ass and rip turns suddenly courses started changing and and some got really technical
FIS decided to start making rules concerning minimum length and limits on sidecut depth
there was another thread about this here about a year ago

[bobdea]

about ski sidecut http://www.bomberonline.com/VBulletin/showthread.php?s=&threadid=977