The null hypothesis and a heretical suggestion about brushes?
russl...@hotmail.com
What I haven't seen is any evidence for those claims. If readers know
of any such tests, please let me know - while I find race stories
interesting, they aren't evidence in the sense I'm using the word.
The null hypothesis, as most of you know, simply states that there is
no demonstrable, statistically significant, difference between A and B.
In this case I'll call A the copper brush and B a similar but
non-copper brush (bronze, soft steel, etc.). To REJECT the null
hypothesis and show that A and B have different effects on ski speed
you would have to test them against each other, e.g., with matched
skis/waxes, etc., through a speed trap and carry out the appropriate
statistics on the test results.
The companies that sell these brushes such as Toko and Swix, just to
name two, have been testing waxes for years - at least 60 years in
Swix's case. And I have no bone to pick with either company - I use
and like their products.
But I think it would be simple for them to test brushes the same way
they test waxes: brush several pairs with A, several pairs with B and
test them with the protocols they use when testing waxes. The skis
could be re-waxed and re-brushed multiple times, they could be skied-in
by skiers, they could be tested over a period of months or even years.
I assume they haven't done that (to my knowledge - if the data are out
there, please let me know) and appear instead to rely on advertising to
persuade us to buy one brush or the other. Or they did the tests,
couldn't find a difference, and could see no point in telling us that -
an entirely understandable decision.
Indirect "tests" may exist - these threads often refer to one brush or
another creating microscopic hairs that slow the ski and then seal the
base when heated. Again, has anyone ever tested those claims?
Many of you probably recall the debates that fueled the audio magazines
(and may still for all I know) about whether a separate amp and pre-amp
would improve sound quality over that of a decent integrated tuner.
Stereo Review did some tests with the ABX procedure and was not able to
reject the null hypothesis: tuners produced sound indistinguishable
from separates.
I don't know of a comparable test-oriented magazine for skiers and the
brush manufacturers provide us with advertising but not test data.
Until there is some evidence, for or against one brush, isn't it
justifiable to assume that there isn't any difference?
BTW, I'm not putting anyone down and I'm just as susceptible to ads as
the next guy, as my brush collection shows.
rjjkk...@sbcglobal.net
variables to control for, you ought to be finished about the same time
that global warming kills the sport.
Randy
Zeke
rjjkk...@sbcglobal.net wrote:
> Well, show us the data when you finish your research. With so many
> variables to control for, you ought to be finished about the same time
> that global warming kills the sport.
>
> Randy
What's your point?
ro...@invalid.net
control the variables involved, anymore than he investigated Stereo
Review's claim of not being able to hear differences between audio
components (the latter goes back decades and presumably has to do with
the relatively poor sonic quality of mass market components made by
their big buck advertisers).
As for brushes, my sense of it is that top level wax techs do all
sorts of things that marketing departments wouldn't want to advertise.
It would seem that the main thing is to know what you want to
accomplish with each brush or tool, and see it that's occurring. Ask
for advice from other experts who don't have a stake in the sales of
one or another brand.
russl...@hotmail.com
In the ski world as I know it we prep skis largely by conventional
wisdom: reps, fast skiers, our pals in the ski shop and our buddies
all have ideas about the best way to do it. I'm certain a lot of it is
good advice, just as I'm certain that some of it will be found to be
wrong - same thing in medicine, psychology, any field.
The copper brush is VERY popular (I use one and have nothing against
it) and might even be reaching the status of the white nylon, that is,
you can/should use it just about every time you wax - cold wax, medium
temp wax, warm wax.
If that's true it makes the variables easier, not harder, to control:
test it when you wax cold, when you wax medium, and when you wax warm,
in comparison to the glide speed of the skis brushed with the
non-copper.
If it's truly a superior tool (while the other is, as one person called
the bronze brush, the "brush of death,") it shouldn't take years of
waxing, ironing and brushing to find out. It's the near-universality
of its recommended use (according to the manufacturers and the much
more experienced skiers I know) that should make the test relatively
easy.
(I didn't intend to offend anyone by bringing up Stereo Review and ABX
sound testing - it's not that germane to this.)
ro...@invalid.net
same conditions, the rest of the wax job identical, the previous speed
of the skis identical, clean brushes with equal wear, brushing
calibrated to be equal relative to the nature of the brushes
(pressure and number of strokes) ... what am i leaving out?
DMK
difference would come in the time it takes to brush your skis out. I
may be off base but I think you could get top notch brushing results
with a quiver of toothbrushes it you had lots of time and patience.
Personally I like the copper because it takes quite a bit of wax out
quickly and like others have said, it doesn't appear to add any
structure to the ski. Follow with white nylon or horse hair then a
polishing brush and call it good. I think most of what is said about
brushes is marketing speak.
DMK
Zach Caldwell
Brushes are used to remove wax and to polish or work-harden the base.
We're not talking about the type of base modifications that wax and
structure make. All things being equal you'd have a very hard time
finding ski-speed performance differences between brushes unless you
simply didn't manage to do the required job with one of them. That
should be plainly evident to the eye. No need to use a speed trap to
determine that you haven't got the wax off the ski base!
That's not to say there aren't differences between brushes. Generally I
do 90% of my brush work with one brush. My current favorite is the new
fine steel brush from Swix. The Toko copper brush works well also. I'm
not a big fan of the various bronze brushes. The criteria for a good
brush is that it should not physically move base material, it should
quickly remove wax, and it shouldn't clog up. All of these metal
brushes need to be broken-in carefully before you use them on good skis
to meet the first requirement.
Once you've removed the wax a hard nylon brush works well to polish the
base. You can "scrub" in both directions at this point in the process,
and use quite a lot of pressure.
On the whole the process should be quite fast, and somewhat tiring.
I've seen many people ritualize their brushing practices - count
strokes, go through specific orders of brushes and change them for
different waxes. On the whole it's safe to say that this won't make a
difference. Find a good metal brush that won't destroy your base and
use it for 90% of your work. Then find a good polishing brush. And
you're all set!
Zach
Bjorn A. Payne Diaz
good scientific conclusions about ski speed, your final result will not
be believed by a significant proportion of people. People have their
beliefs, and it's hard to sway them from those beliefs.
As for testing skis, almost no one has closely matches pairs of skis. I
did my testing by using two pair (call them pair A, and pair B), and
then intermixing those skis. So one ski from pair A and one ski from
pair B would get Swix HF6, and the other ski from pair A and the other
ski from pair B would get Toko HF Red. This then assumes the left and
right ski in each pair is equal both in flex and grind. (A pretty
decent assumption.) You can only compare two waxes in this way.
In order to glide test the skis with a timer, you have to glide in
tracks. Each run down the tracks makes the tracks glaze. So usually you
alternate the skis and record each time, then graph the results with a
line, and look for a gap between the two lines. The glide also depends
on the hill incline, and the timing marks (magnets in the snow) should
be placed after you're up and gliding and before you slow significantly
at the bottom.
It's fun when people yank your magnets out the snow, look at them, and
then toss them into the deep stuff. (Yes it happens.)
One problem is gusty winds. Another difficulty is trying to start
exactly the same, tuck exactly the same each run, and have good balance
since all those are hidden factors in speed. Another factor is how far
the skis have been skied. Skis should probably be tested for initial
speed, be skied a good 2-5 km, and then tested again. Significant
differences are usually in tenths of a second, and I think it's
important to graph each of the points and simple to SD analysis on the
numbers (since that can hide trends).
With all of that said, I agree with Zach that I don't believe it would
be easy to detect a difference in brushes, and hard to establish a
defined end point for brushing. There would likely be a large
difference for slightly underbrushing a ski as compared to using two
different brushes.
I think the metal brushes have become popular because they really speed
up brushing (and, for the most par, blow away rotobrushes). I again
agree with Zach that it's probably a good idea to break in the Swix
fine metals before using them for race wax jobs. (They're really sharp
when they're new.) If you use the brush exclusively in one direction,
they're very sharp in the opposite direction, even when they're well
used. The Toko copper has less of this effect, but it's still there.
As for rotobrushes, they're great for polishing...
Jay
Norski
Is it worth while to build and setup a glide down timer? With all the
changing variables during the testing, maybe different
temperature/conditions come race day, conditions changing during the race
(temperature usually warming as the day goes on) and the fairly wide range
waxes will work in.
Zach did glide down tests the day before the Birkie and recorded the
times. Mike Wynn picked the same wax/grind that was the fastest recorded by
the timer, just by using feel. He put one wax/grind ski combination on one
foot and another combination on another foot. I've seen elite skiers pick
their race wax the same way, by just using feel.
--
Paul Haltvick
Bay Design and Build - LLC
Engineering, Construction and Information Technology Services
FSx - Fischer / Swix Racing
"Bjorn A. Payne Diaz" <wenner...@gmail.com> wrote in message
news:1162215535.2...@i42g2000cwa.googlegroups.com...
Camilo
> My two cents:
As usual, worth much, much more than that!
......
> All of these metal
> brushes need to be broken-in carefully before you use them on good skis
> to meet the first requirement.
I read a lot on line and in publications about ski prep, but I have to
say this is the first I've heard about breaking a brush in. Maybe I
missed something. Could you elaborate on this?
I'm using a Toko copper brush for almost all of my brushing. It's a
couple of years old and has done many dozens of skis. I tend to not
bear down very hard, thinking the more "vertical" the bristles are
vis-a-vis the ski surface, the better they'll reach into the structure
and brush out the wax. I tend to swap the brush end for end regularly,
because I've seen copper brushes whose bristles are totally bent back
in one direction and I'm trying to keep mine nice and straight. No one
has told me to do this, but it seemed to make sense to me. Maybe
that's an error?
> Once you've removed the wax a hard nylon brush works well to polish the
> base. You can "scrub" in both directions at this point in the process,
> and use quite a lot of pressure.
Could you elaborate on this as well? This is a step I've often been a
little unclear about. I have three brushes that I use: fine copper,
white (stiff) nylon, and stiff short horsehair. Like you, I use the
metal for most of the brushing. The horsehair, I've heard various
recommendations for - one being as a final step, the other being a wax
removal brush for fine structure. But it doesn't "polish" as far as I
can tell - the surface actually can look duller if I use it last. What
IS the purpose of a horsehair brush?
I generally have used the Swix white nylon brush after the copper,
because it does shine up the surface. But I'm wondering why I bought
the horsehair?
> On the whole the process should be quite fast, and somewhat tiring.
> I've seen many people ritualize their brushing practices - count
> strokes, go through specific orders of brushes and change them for
> different waxes. On the whole it's safe to say that this won't make a
> difference. Find a good metal brush that won't destroy your base and
> use it for 90% of your work. Then find a good polishing brush. And
> you're all set!
(AA Mode ON) Hello, I am a ritualistic brusher....
I'I definitely tend to ritualize my routine, just because it just helps
me move from one ski to the other and get the job done at a decent
level and roughly equal "quality" for all the skis. This is a family's
worth of skis, some racing, none super competative. With my ritual, I
can assume there will be no really poorly brushed skis and I'll have
enough energy left to do the 4th (or 8th or 12th!)ski as well as the
1st! My goal is always to do a "pretty good" job, but I understand it
is not as good as it can possibly get. If I'm doing a pair for an
actual race I might actually examine the skis to see how they're
looking and brush more if necessary. But, the deciding factor is always
just getting the job done decently given the time and ENERGY I have,
not the last tiny bit of speed. But I so pretty much only include two
brushes in my ritual, so the ritual is not too obsessive. It is indeed
pretty quick (per ski) and tiring.
I really appreciate your philosophy though - KISS, and it's great to
hear a pro espouse it. It certainly applies to what I do.
Thanks for your comments!
Bjorn A. Payne Diaz
Toko has a great timer for this purpose...about $65 as I remember. I
got it cheaper since it sat on the shelf a few years (shows how much
people want to test skis).
Feel can be a great way to compare skis, and that's how I think most
people pick their skis on race day. Of course usually you're checking
out the skis an hour before the start, and by the middle of the race,
it may be 20 degrees warmer, but it's still good to know what's gliding
so you can make a good guess for the race.
Jay
rjjkk...@sbcglobal.net
Talk to Bert Kleerup of Eagle River Nordic. He's chased data like this
for a lifetime, and he's trained as a statistician. Like I said, get
back to us with the data. . .
Randy
ro...@invalid.net
>. . . same stone grind, same binding position. . . .etc., etc.
>
>Talk to Bert Kleerup of Eagle River Nordic. He's chased data like this
>for a lifetime, and he's trained as a statistician. Like I said, get
>back to us with the data. . .
>
>Randy
Good idea. Do check if his numbers are from on snow tests, the shop
bench or the manufacturer?
russl...@hotmail.com
rjjkk...@sbcglobal.net wrote:
> . . . same stone grind, same binding position. . . .etc., etc.
>
> Talk to Bert Kleerup of Eagle River Nordic. He's chased data like this
> for a lifetime, and he's trained as a statistician. Like I said, get
> back to us with the data. . .
>
> Randy
Randy,
Thanks for taking the time to reply.
I don't think it is within reach for any individual, even one who loves
the sport and makes his living in the ski retail business, to do the
necessary tests.
Swix published a photo of their wax-testing device from 1946: weighted
skis, multiple tracks, what looks like an automated start device and, I
would guess, matched skis that could be moved from one track to another
to control for track differences.
Most companies test their products, ski wax/brush companies included.
I'd like to see them offer some data, not just advertising. Even
"indirect" tests would be helpful, e.g. " Our brush removes more wax,
more quickly, creates fewer hairs, and with less change in structure
than the brush from the other guys, by actual observation."
I say "indirect" because we wouldn't know if differences like those
translated into signficant speed differences, although we would expect
them to. If brush makers don't test brushes before releasing them I
wonder why.
We've all seen ski products come in to favor then disappear as we
learned the hard way (with our purchases and trial and error
experience) that they didn't live up to the hype.
Russ
ro...@invalid.net
>Most companies test their products, ski wax/brush companies included.
>I'd like to see them offer some data, not just advertising. Even
>"indirect" tests would be helpful, e.g. " Our brush removes more wax,
>more quickly, creates fewer hairs, and with less change in structure
>than the brush from the other guys, by actual observation."
Let's say it were possible to measure what you're looking for. You'd
believe the manufacturers' data? What's the practical difference
between advertising and the data companies release (for ex., drug
companies)? How would you sort out contradictory claims, as would most
obviously occur between brands, and even within? In effect, wax
companies and their reps and skiers do provide data - anecdotal. An
independent expert did here too - Zach. I'm afraid that's about the
best you're going to get.
rm
russl...@hotmail.com
ro...@invalid.net wrote:
> Let's say it were possible to measure what you're looking for. You'd
> believe the manufacturers' data? What's the practical difference
> between advertising and the data companies release (for ex., drug
> companies)? How would you sort out contradictory claims, as would most
> obviously occur between brands, and even within? In effect, wax
> companies and their reps and skiers do provide data - anecdotal. An
> independent expert did here too - Zach. I'm afraid that's about the
> best you're going to get.
>
> rm
rm
Good point. I've very glad for the information I get from reps, Zach,
Jay, etc., information that influences my purchases.
Would I automatically accept the manufacturer's data? Of course not.
But do I want them to provide data? You bet.
Let's turn your argument about drug companies around - do we want them
to give us no data? It was just because they gave us data that didn't
hold up that we were able to go back to them (and to the researchers
and the journals) and say "you have to do a better job." Some people
will suffer severe consequences for publishing bogus drug data.
My point, which I haven't expressed very well, is that in the ABSENCE
of data, we can't say A is better than B. And I agree w/Randy (who may
be surprised to hear this) that an individual skier can't test these
products himself. See Jay's earlier post on this thread for the
difficulties he ecncountered comparing two waxes.
I assume Swix, Toko, etc., are good companies trying to make products
that we'll continue to purchase for years, and that they usually have
data on the effectiveness of the various materials they use like
bronze, copper, soft steel, etc., but they don't feel they have to
share it. I'd just like them to pass it along to us.
You mentioned the reps giving us anecdotal data - sometimes it's useful
but sometimes it isn't. When Swix introduced the CH7, LF7, HF7 waxes
(for temps between the waxes numbered 6 and 8) it was accompanied by a
relabeling of the temperature ranges for the 6s and 8s. I asked the
rep what changed, the formulations of the 6s and 8s or just the temp
ranges printed on the package. He said he didn't know but guessed the
only change was what was printed on the packages.
I didn't start this post to tick anyone off, just to point out that
we're still in the "snake-oil" stage of product comparison, to go back
to the drug analogy. Salesmen tell us their product is great, we try
it, and make up our own minds. Our wax boxes are full of things (mine
is, anyway) that didn't pan out.
You're right, rm: as it is now, Zach and the reps and other skiers are
the best we have.
I'd just like the companies to give us any data they have. What we do
with it is an individual choice. That's it in a nutshell.
thanks,
russ
ro...@invalid.net
either/or, but any. That's why next of kin and people who grow third
arms from some drug with "good data" hire lawyers. I get the strong
sense that you are looking for any information at all from wax
companies that will make you feel more comfortable brushing your skis,
no matter how much of that information is good coin or adulterated crap
or some combination of the two. Understandable, but I'm afraid it's a
set up for disappointment. Good luck.
rm
russl...@hotmail.com wrote:
>rm
russl...@hotmail.com
r...@invalid.net wrote:
> Haloween is over now, so you can take down the straw man. It's not
> either/or, but any. That's why next of kin and people who grow third
> arms from some drug with "good data" hire lawyers. I get the strong
> sense that you are looking for any information at all from wax
> companies that will make you feel more comfortable brushing your skis,
> no matter how much of that information is good coin or adulterated crap
> or some combination of the two. Understandable, but I'm afraid it's a
> set up for disappointment. Good luck.
rm:
Halloween? Straw man? I missed that.
I want to be polite, but I never used the words "good data" re drug
companies; in fact, I said they're in trouble for giving "bogus drug
data."
This thread is getting way, way off track - if you're happy with the
data, or lack of it, from the ski companies, then I'm happy for you.
Good luck to you as well,
Russ
Bjorn A. Payne Diaz
russl...@hotmail.com wrote:
> You mentioned the reps giving us anecdotal data - sometimes it's useful
> but sometimes it isn't. When Swix introduced the CH7, LF7, HF7 waxes
> (for temps between the waxes numbered 6 and 8) it was accompanied by a
> relabeling of the temperature ranges for the 6s and 8s. I asked the
> rep what changed, the formulations of the 6s and 8s or just the temp
> ranges printed on the package. He said he didn't know but guessed the
> only change was what was printed on the packages.
I also mix LF4 and LF6 to get "LF5" and CH4 and CH6 to get CH5.
If Swix were to market a 5 series of waxes, I wouldn't expect the 4 and
6 series to change except for recommended temp ranges on the box. I
think the same thing happened with the 7 series of waxes. You could get
a very similar wax by mixing 6 and 8.
Jay
ro...@invalid.net
<Let's turn your argument about drug companies around - do we
want them to give us no data? It was just because they gave us data
that didn't hold up that we were able to go back to them (and to the
researchers and the journals) and say "you have to do a better job."
Some people will suffer severe consequences for publishing bogus drug
data.>
Your paragraph starts with a straw man question and then devolves into
confusion. Do you want data to help with your skis or to expose and sue
the wax companies, to tell them they have to do a better job? Geesh,
go mix waxes and brush your skis already with copper or thin steel or a
toothbrush. You really believe all that stuff about Vioxx or whatever
was about telling drug companies they have to do a better job? I got
some land out west...
russl...@hotmail.com
Bjorn A. Payne Diaz wrote:
>
> If Swix were to market a 5 series of waxes, I wouldn't expect the 4 and
> 6 series to change except for recommended temp ranges on the box. I
> think the same thing happened with the 7 series of waxes. You could get
> a very similar wax by mixing 6 and 8.
>
> Jay
Jay,
Thanks for the comments.
I wouldn't know what to conclude had happened in the factory, but I
think your suggestion is as good as any and it's what the rep guessed
had happened w/6 and 8.
It seems possible (to me) that 7 is simply 6 and 8 blended at the
factory. If so, I have no bone to pick w/Swix - 7 is a very useful
wax. I use Swix 4 through 10 and, like you, have mixed two adjacent
waxes at times.
When Swix changed it's glide line to "CH" I wondered if one of them
was meant to be a successor to the very popular Violet. Maybe Swix or
the reps passed along some info that I missed out on; or maybe they
just assumed, correctly, that we'd buy the waxes and work it out on our
own.
Russ
russl...@hotmail.com
Norski wrote:
> Jay,
> Is it worth while to build and setup a glide down timer? With all the
> changing variables during the testing, maybe different
> temperature/conditions come race day, conditions changing during the race
> (temperature usually warming as the day goes on) and the fairly wide range
> waxes will work in.
> Zach did glide down tests the day before the Birkie and recorded the
> times. Mike Wynn picked the same wax/grind that was the fastest recorded by
> the timer, just by using feel. He put one wax/grind ski combination on one
> foot and another combination on another foot. I've seen elite skiers pick
> their race wax the same way, by just using feel.
>
> --
>
> Paul Haltvick
> Bay Design and Build - LLC
> Engineering, Construction and Information Technology Services
> FSx - Fischer / Swix Racing
Paul,
re your reply to Jay: I think this is a great suggestion, especially
on race morning if you have two or 3 pairs you want to compare - skiing
one ski of each pair for a few Ks combines your evaluation of the ski
with your warmup and can be a low stress (both physical and
psychological stress) way to make a decent choice.
Russ
rjjkk...@sbcglobal.net
testing and snow testing, over many years. He was probably the first
to design and build a usable machine to measure the flex pressure
profile of skis, which he still uses to test skis before selling them.
He's measured the drag of weighted skis pulled over various tracks and
conditions. I've seen skis in his shop wired up with may sensors of
some type. I always learn something new when I talk to him, and his
stories of a life in the sport are wonderful.
In spite of pursuing passionately the arcane science of what makes skis
glide and grip and handle over many years, Bert would be the first to
tell you the limitations of his work. He knows this because of his
training as a statistition. Because there are so many variables in
play, many of which cannot be controlled for, and probably some we
don't even know exist, it takes an enormous amount of data to sift
through to get any meaningful results. Does that mean all of the work
done in this area is useless? No, but like everything else, the more
you know, the more you realize how little you know for sure. (Oh man,
that sounds way too much like Donald Rumsfeld. . . )
Randy
Norski
I took the suggestion from you and Jay. This morning I ordered one of
the Toko timing units. It should be a good way to actually record the time
of skis through a 'speed trap' rather than trying to pick skis based on how
far a ski glides before coming to a stop.
The units do not seem to be very popular. New Moon ski shop was closing
the units out. Usually $69 but now on sale for $45. They are also having a
sale this weekend, so I got another 15% off that, which makes the deal even
sweeter.
Thanks again for the advice.
--
Paul Haltvick
Bay Design and Build - LLC
Engineering, Construction and Information Technology Services
FSx - Fischer / Swix Racing
<russl...@hotmail.com> wrote in message
news:1162743314.6...@h54g2000cwb.googlegroups.com...