Usual wax pocket theory seems wrong...

The usual way of approximately locating the wax pocket of a classical
ski is to stand on both skis, equally, and slide a paper under them.
Where the paper binds is the outer limits of the pocket. Official
doctrine says the wax pocket keeps the kick wax off the snow when
gliding or doublepoling.

No, it doesn't!

It only works for 2-footed gliding and part of doublepoling.

It seems to me that the best wax pocket would be one where the kick
wax is off the snow when ALL your weight is on one ski --- that's the
condition in which MOST gliding occurs.

It then seems that the camber should be designed to collapse only when
one kicks or steps off of the ski, putting MORE than 100% of body
weight onto the ski.

With the way my skis are now when I glide while diagonal striding I'm
contacting the snow and causing friction with about 50% of my kickwax
zone.

Only when we use the klister zone is all the kickwax off the snow
during the diagonal stride glide.

I'm thinking that all classic skis should have wax pockets that
function like a klister zone. Klister skis should just have higher
pockets because klister is thicker.

So, what am I missing?

I suppose I'm missing the possibility that lightly weighted kickwax
works like a glide wax. ? Seems unlikely.

Another angle is that a ski track isn't like a floor. ...Then again
many ski tracks are firm like a floor. Given the irregularites of a
track it almost seems like a kickzone should be higher off the ground,
yet still collapse easily with the amount of pressure a kick
generates.

Maybe a kick doesn't generate more than bodyweight?

Maybe kickwax doesn't cause friction when it's moving/gliding and only
works when it STOPS. Unlikely. Kickwax causes lots of friction. But
maybe if kicking isn't more than bodyweight then we just have to put
up with this friction?

Anyway, if there's a difference between the weighting of a ski when we
glide on it while diagonal striding and when we kick on it then the
ski-makers should isolate that difference and build their kickzone
around that. ...So it offhand seems to me.

--JP

On Mar 26, 11:38*am, jeff potter wrote:
The usual way of approximately locating the wax pocket of a classical
ski is to stand on both skis, equally, and slide a paper under them.
Where the paper binds is the outer limits of the pocket. Official
doctrine says the wax pocket keeps the kick wax off the snow when
gliding or doublepoling.

No, it doesn't!

It only works for 2-footed gliding and part of doublepoling.

It seems to me that the best wax pocket would be one where the kick
wax is off the snow when ALL your weight is on one ski --- that's the
condition in which MOST gliding occurs.

It then seems that the camber should be designed to collapse only when
one kicks or steps off of the ski, putting MORE than 100% of body
weight onto the ski.

With the way my skis are now when I glide while diagonal striding I'm
contacting the snow and causing friction with about 50% of my kickwax
zone.

Only when we use the klister zone is all the kickwax off the snow
during the diagonal stride glide.

I'm thinking that all classic skis should have wax pockets that
function like a klister zone. Klister skis should just have higher
pockets because klister is thicker.

So, what am I missing?

I suppose I'm missing the possibility that lightly weighted kickwax
works like a glide wax. ? *Seems unlikely.

Another angle is that a ski track isn't like a floor. ...Then again
many ski tracks are firm like a floor. Given the irregularites of a
track it almost seems like a kickzone should be higher off the ground,
yet still collapse easily with the amount of pressure a kick
generates.

Maybe a kick doesn't generate more than bodyweight?

Maybe kickwax doesn't cause friction when it's moving/gliding and only
works when it STOPS. Unlikely. Kickwax causes lots of friction. But
maybe if kicking isn't more than bodyweight then we just have to put
up with this friction?

Anyway, if there's a difference between the weighting of a ski when we
glide on it while diagonal striding and when we kick on it then the
ski-makers should isolate that difference and build their kickzone
around that. ...So it offhand seems to me.

--JP

Dear Jeff:

First of all, remember back to when we skied on wooden skis. Okay,
I'm that old. Anyway, one waxed the entire pine-tarred ski bottom
with kick wax. So, yes, well chosen kick wax will glide. If you've
taken beginning physics, it's the difference between the static and
dynamic coefficients of friction that allow both kick and glide, if
you've chosen well.

That being said, of course there is a difference between our modern
glide wax and kick wax, and the less kick wax one can get away with,
the faster the glide can be. Several of our Michigan Cup races this
year had folks "classic" skiing on skate skis, to good effect. ( I
hate you, Chip!) I watched the World Cup Classic sprint from Canmore
last year, and all of the podium finishers went with skate skis. How
they're able to double pole up those steep climbs (I've been there!)
is beyond me, but they blew away the field on the flats and descents.

The last pair of classic skis I had ground by Mark Wachter also have
three zones marked as to height of the ski surface off of the snow, I
think in tenths of millimeters. You could probably use the shortest
zone in all hard tracks, whether hard wax or klister, because the snow
won't shear. In soft track with fresh snow, a longer kick zone kicks
on a longer area of snow, and therefore won't shear away and slip.

Gotta go. . .

Randy Bladel

Jeff,

How many pairs of skis do you have? It seems you're constantly having
problems with your skis.

I think that you should contact a very high end dealer in skis -- say
something like Boulder Nordic Sport -- and just buy a small number of
pairs of skis that fit you exactly right and be done with your
troubles. At least you can get some racing style classic skis that
are near perfect like that.

I've found that the best shops or ski fitters consider the
stand-on-the-ski test to be useless at best. Rather, in addition to
visually and by feel evaluating how a pair closes by hand - you can
learn a lot that way - they employ a well-engineered flex tester. The
idea is to measure how much weight (relative to the skier's) and force
it takes (relative to their kick) to get the ski's camber closed or in
the glide position. For instance, starting at the beginning, if a
Fischer classical ski measures 44.5, +4, .40, if I've got it right that
means the ski takes 44.5 kg to close to .20mm (two thin layers), 4 more
kg to close it to .10 (the "finish," standard measure of ski closed),
and the half-weight camber height (open gliding) is .40mm. From there,
they can work up and down the center of the ski to get exact
measurements for degree of opening in the glide position (higher in the
middle, less toward front and back). That gives you a theoretical wax
pocket and how much wax to put there. Then you have to take those
measurements out on the snow, preferably having waxed a bit longer, and
see how it wears (variations per conditions, of course). For a good
explanation, see
http://www.caldwellsport.com/ski-ser...ex-evaluation/, and the pdf.

Gene

jeff potter wrote:

The usual way of approximately locating the wax pocket of a classical
ski is to stand on both skis, equally, and slide a paper under them.
Where the paper binds is the outer limits of the pocket. Official
doctrine says the wax pocket keeps the kick wax off the snow when
gliding or doublepoling.

No, it doesn't!

It only works for 2-footed gliding and part of doublepoling.

It seems to me that the best wax pocket would be one where the kick
wax is off the snow when ALL your weight is on one ski --- that's the
condition in which MOST gliding occurs.

It then seems that the camber should be designed to collapse only when
one kicks or steps off of the ski, putting MORE than 100% of body
weight onto the ski.

With the way my skis are now when I glide while diagonal striding I'm
contacting the snow and causing friction with about 50% of my kickwax
zone.

Only when we use the klister zone is all the kickwax off the snow
during the diagonal stride glide.

I'm thinking that all classic skis should have wax pockets that
function like a klister zone. Klister skis should just have higher
pockets because klister is thicker.

So, what am I missing?

I suppose I'm missing the possibility that lightly weighted kickwax
works like a glide wax. ? Seems unlikely.

Another angle is that a ski track isn't like a floor. ...Then again
many ski tracks are firm like a floor. Given the irregularites of a
track it almost seems like a kickzone should be higher off the ground,
yet still collapse easily with the amount of pressure a kick
generates.

Maybe a kick doesn't generate more than bodyweight?

Maybe kickwax doesn't cause friction when it's moving/gliding and only
works when it STOPS. Unlikely. Kickwax causes lots of friction. But
maybe if kicking isn't more than bodyweight then we just have to put
up with this friction?

Anyway, if there's a difference between the weighting of a ski when we
glide on it while diagonal striding and when we kick on it then the
ski-makers should isolate that difference and build their kickzone
around that. ...So it offhand seems to me.

--JP

On Mar 26, 1:47*pm, John Forrest Tomlinson
wrote:
Jeff,

How many pairs of skis do you have? *It seems you're constantly having
problems with your skis.

This is a camber theory question---mostly questioning the value of
half-weight camber.

I also recently had a nowax theory question.

I've only had a complaint about my touring waxable skis --- my fave
local pro shop only got that ONE pair in all year so I wasn't in a
great position to be picky --- also I didn't know as much then about
touring skis as I do now. Before my great old tour skis broke I had no
complaints there. (I would've been be VERY impressed if the shop that
carried the Fischer tour skis that I recently got had said, "Whoa,
don't get these, they have soft tails that'll crash ya and they're
heavy-feeling so get "X" instead or search eBay for some great old
ones." Do shops even do flex testing for same-size tour skis or know
what the optimal flexes are for touring? Maybe a good shop would've
recognized and thrown out the ones I got...)

I do have a pair of extremely light and quite soft 1992 Rossi's top
race skis in skate and classic that serve me well in races. I don't
think I've complained lately about race ski theory.

Yeah, I wish I had a ski budget and a shop that had a wide range of
flexes in a wide range of skis that I use so that I could get a good
fit on every pair, but...

I still would likely end up with ski theory questions!

--JP

On Thu, 26 Mar 2009 13:41:01 -0700 (PDT), jeff potter
wrote:

Yeah, I wish I had a ski budget and a shop that had a wide range of
flexes in a wide range of skis that I use so that I could get a good
fit on every pair, but...

I was only suggesting that because I have the impression you keep
getting skis that don't work right, which is a false economy even if
they're cheap. If you get skis that work just right, perhaps that'll
make it worth spending a lot on those one or two pairs.

On Mar 26, 8:38*am, jeff potter wrote:

It seems to me that the best wax pocket would be one where the kick
wax is off the snow when ALL your weight is on one ski --- that's the
condition in which MOST gliding occurs.


Another angle is that a ski track isn't like a floor. ...Then again
many ski tracks are firm like a floor. Given the irregularites of a
track it almost seems like a kickzone should be higher off the ground,
yet still collapse easily with the amount of pressure a kick
generates.


--JP

Both Zack Caldwell and Mark Waecher load both the 8 cm and 15 cm back
points with the 15 cm back point simulating full weight loading. Zack
notes that at full weight 15 cm back, he checks to see if the grip wax
pocket forward is still open.

My Atomic's pretty much work the way Zack says. My cold Atomics are
easy closing skis (55% of body weight to 0.2mm and an additional 2 kg
to close). I found that I pretty much lost all of my grip wax back of
the balance point after a classic marathon even using green klister as
a base binder. Even with the easy closing, the glide well. The down
side is wax loss after 30+ km.

Edgar

On Mar 26, 11:38*am, jeff potter wrote:
The usual way of approximately locating the wax pocket of a classical
ski is to stand on both skis, equally, and slide a paper under them.
Where the paper binds is the outer limits of the pocket. Official
doctrine says the wax pocket keeps the kick wax off the snow when
gliding or doublepoling.

No, it doesn't!

It only works for 2-footed gliding and part of doublepoling.

It seems to me that the best wax pocket would be one where the kick
wax is off the snow when ALL your weight is on one ski --- that's the
condition in which MOST gliding occurs.

It then seems that the camber should be designed to collapse only when
one kicks or steps off of the ski, putting MORE than 100% of body
weight onto the ski.

With the way my skis are now when I glide while diagonal striding I'm
contacting the snow and causing friction with about 50% of my kickwax
zone.

Only when we use the klister zone is all the kickwax off the snow
during the diagonal stride glide.

I'm thinking that all classic skis should have wax pockets that
function like a klister zone. Klister skis should just have higher
pockets because klister is thicker.

So, what am I missing?

I suppose I'm missing the possibility that lightly weighted kickwax
works like a glide wax. ? *Seems unlikely.

Another angle is that a ski track isn't like a floor. ...Then again
many ski tracks are firm like a floor. Given the irregularites of a
track it almost seems like a kickzone should be higher off the ground,
yet still collapse easily with the amount of pressure a kick
generates.

Maybe a kick doesn't generate more than bodyweight?

Maybe kickwax doesn't cause friction when it's moving/gliding and only
works when it STOPS. Unlikely. Kickwax causes lots of friction. But
maybe if kicking isn't more than bodyweight then we just have to put
up with this friction?

Anyway, if there's a difference between the weighting of a ski when we
glide on it while diagonal striding and when we kick on it then the
ski-makers should isolate that difference and build their kickzone
around that. ...So it offhand seems to me.

--JP

Jeff:

Another way to determine your kick wax pocket is to wax a little
longer than you think the pocket is with a soft wax, and then go ski,
especially in abrasive conditions. If you ski long enough, you will
be able to see and feel with your hand where the wax has worn away
to. What's left is your wax pocket, at least for those conditions.

I think the Fischer race ski "912" construction (or something like
that) is supposed to not contact the snow until you really kick it
down, addressing your concern.

In the early days of composite race skis, it was harder to kick down
and "set" the wax. The american team used to boast that Bill Koch
could kick down with some multiple of his body weight, which I can't
recall. Kniessel or Peltonon had a ski with a knob just in front of
the binding that you could turn to adjust the stiffness of the wax
pocket, using a Kevlar strap inside the ski. Bert Kleerup had a pair
in his shop, and said some Russian used that model in competition.
You would soften them up for the climbs and harden them up for the
descents and flats, I guess.

Randy Bladel

On Mar 26, 11:38*am, jeff potter wrote:
The usual way of approximately locating the wax pocket of a classical
ski is to stand on both skis, equally, and slide a paper under them.
Where the paper binds is the outer limits of the pocket. Official
doctrine says the wax pocket keeps the kick wax off the snow when
gliding or doublepoling.

No, it doesn't!

It only works for 2-footed gliding and part of doublepoling.

It seems to me that the best wax pocket would be one where the kick
wax is off the snow when ALL your weight is on one ski --- that's the
condition in which MOST gliding occurs.

It then seems that the camber should be designed to collapse only when
one kicks or steps off of the ski, putting MORE than 100% of body
weight onto the ski.

With the way my skis are now when I glide while diagonal striding I'm
contacting the snow and causing friction with about 50% of my kickwax
zone.

Only when we use the klister zone is all the kickwax off the snow
during the diagonal stride glide.

I'm thinking that all classic skis should have wax pockets that
function like a klister zone. Klister skis should just have higher
pockets because klister is thicker.

So, what am I missing?

I suppose I'm missing the possibility that lightly weighted kickwax
works like a glide wax. ? *Seems unlikely.

Another angle is that a ski track isn't like a floor. ...Then again
many ski tracks are firm like a floor. Given the irregularites of a
track it almost seems like a kickzone should be higher off the ground,
yet still collapse easily with the amount of pressure a kick
generates.

Maybe a kick doesn't generate more than bodyweight?

Maybe kickwax doesn't cause friction when it's moving/gliding and only
works when it STOPS. Unlikely. Kickwax causes lots of friction. But
maybe if kicking isn't more than bodyweight then we just have to put
up with this friction?

Anyway, if there's a difference between the weighting of a ski when we
glide on it while diagonal striding and when we kick on it then the
ski-makers should isolate that difference and build their kickzone
around that. ...So it offhand seems to me.

--JP

Hi again, Jeff:

Remember also, that in diagonal stride or kick-double pole, that a
good portion of your weight is taken off of your single gliding ski by
your arm and pole (for diagonal) or both arms and poles (kick-double
pole).

Also, the weighting of the ski is a dynamic thing, not just an
unchanging force in the middle of the ski. A good skier is
"unweighting", maybe subtley, while gliding on that single ski as a
preparation for "weighting" when they kick, and therefore keeping the
wax off of the snow while gliding.

Thirdly, many racers rarely put kick wax as far back as the heel, and
then glide with their weight on the heel as much as possible.

Randy

On Mar 26, 4:50*pm, wrote:
On Mar 26, 8:38*am, jeff potter wrote:


Another angle is that a ski track isn't like a floor. ...Then again
many ski tracks are firm like a floor. Given the irregularites of a
track it almost seems like a kickzone should be higher off the ground,
yet still collapse easily with the amount of pressure a kick
generates.

--JP

I should add that the flex/camber testing that Zack and Mark do are
only as good as their skill at interpreting the results., As Jeff
notes, a ski track isn't a floor. The good ski pickers need to base
thier picks on their experience as to how skis measured as they
measure them would be expected to act on the different snow
conditions. That is, any flex/camber bench test is only a proxy as to
how the skis behave on hard snow, soft snow, etc. So, that said, all
the theory and testing is only as good as to how the data is
interpreted.

Edgar