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Why Are Some Skis Faster?

post #1 of 22
Thread Starter 

 I have one pair of skis that slide slower than my other two.  I wax them all identically. 

 

Fast skis: Elan 666, Elan 888

 

Slow skis: Fischer Atua  

 

When I point them downhill, different things happen.  The Elans go like a scalded ape from the outset.  The Atuas take the scenic route.  This doesn't seem to have anything to do with the way I ski them because it happens when I point them straight downhill on the same run on the same day.  Today I was skiing the Fischers and running a straight line on a groomed cat track. I passed a boarder who was just getting underway yet he passed me later and neither of us was turning, just running straight down the road.  The boader looked smaller than me, so it wasn't because of weight. This would not have happened with the Elans.

 

I like the Fischers best for most of the conditions I encounter but I wish that they moved out like the Elans.  Is there anything I can do to give them a little more zip down the fall line?

post #2 of 22

Are the base structures the same? How about overall wax cycles?

 

Some skis just do seem faster no matter what you do,

 

Terry

 

(FWIW, I'll be in Everson/Bellingham 3/27 to 3/31.)

post #3 of 22

I think to complete the comparison, you need to do another test with the same skis on the same hill but this time put them on edge and carve.

 

Skis go faster carving.  Maybe the Atua will beat the 666, 888 on an edge test though they'll loose a flat test.

 

 

post #4 of 22

.....and a different ski on each foot.  

post #5 of 22
Thread Starter 

 

Quote:
Originally Posted by L&AirC View Post

 

I think to complete the comparison, you need to do another test with the same skis on the same hill but this time put them on edge and carve.

 

Skis go faster carving.  Maybe the Atua will beat the 666, 888 on an edge test though they'll loose a flat test.

 

 

 

That was why I was careful to mention only straight line skiing.  Both sets of Elans go even faster when carving on groomers, but thery're a better carving ski anyway so you would expect that.  The Fischers are fine, but just don't have the zip there.  It's amazingly different.  It almost feels like there is no wax on the Atuas even though I religiously wax them every three ski days.

post #6 of 22

Do a gazillion wax and brush cycles to make it faster.  That does work.

Note that there are different grades of ptex.  Some has more graphite in it - I think tha't the main difference. They're supposed to be faster, they are more expensive.

Sometimes some ptex absorbs more wax than others.  Speed skis - like downhill skis, are often kept for years if they are fast and they just change the graphics.  I remember when Picabo crashed and screwed up her knee and broke one of her skis.  She was very upset about her skis because they were fast.

post #7 of 22

 

 

Try 1-2-3 cycles of a cold LF wax like Dibloc Blue.

 

 

 

 

 

 

 

 

Edit: I'm convinced Fischer rec skis like lubed (moly, graphite, PFPE like Zardoz, or the 3M 739 that Hertel use) wax mixes or fluoro mixes more than other skis do. 

post #8 of 22
Thread Starter 

 

Quote:
Originally Posted by Alpinord View Post

 

Are the base structures the same?

 

(FWIW, I'll be in Everson/Bellingham 3/27 to 3/31.)

 

How do I determine base structure?

 

(If you're heading up to Baker, drop me a line.  Maybe we can make some turns.)

post #9 of 22

 

Just look at the bases; one might have a visibly coarser pattern and the other not.

post #10 of 22

 

Quote:
Originally Posted by comprex View Post

 

 

 

Try 1-2-3 cycles of a cold LF wax like Dibloc Blue.

 

 

 

 

 

 

 

 

Edit: I'm convinced Fischer rec skis like lubed (moly, graphite, PFPE like Zardoz, or the 3M 739 that Hertel use) wax mixes or fluoro mixes more than other skis do. 

 

Or LF Moly (which we just happen to now carry ):

 

post #11 of 22

 

Quote:
Originally Posted by Posaune View Post

 

 

 

How do I determine base structure?

 

(If you're heading up to Baker, drop me a line.  Maybe we can make some turns.)

 

I've been on the fence about schlepping ski gear......we'll see and I'll let you know. Have conditions improved enough to merit the effort?

 

Can you visually or by feel tell any difference in the structure?


Edited by Alpinord - 3/18/2009 at 12:58 am
post #12 of 22

From Tognar Toolworks:

 

What is P-Tex?
P-tex is a tradename for the polyethylene base material used on skis and snowboards. It was originally produced and supplied to ski manufacturers by Inter Montana Sport (IMS) of Switzerland, and, although other companies now produce polyethylene base material under different trade names, just about everyone in the ski and snowboard industry still refers to it as p-tex out of habit.

sintered ptexThere are two types of p-tex used on skis and snowboards today...extruded and sintered.
Extruded p-tex is a low molecular weight polyethylene that is manufactured by heating it to 350 degrees F. and pressure feeding it through a die (or slot) to the desired shape and thickness. It is used as a base material for many recreational skis and snowboards.
Sintered p-tex is made by packing ultra high molecular weight polyethylene powder into a cake that is heated and compressed (sintered) to form a log or billet (see diagram below). A lathe or mill is then used to shave (scive) off a thin layer to the desired thickness.

The advantages of sintered over extruded p-tex are 20-25% higher abrasion and impact resistance, a very low coefficient of friction, and the ability to absorb over 3 times more wax. Accordingly, sintered p-tex is found on the bases of most racing and high performance skis and snowboards.

Electra base is a sintered p-tex to which 15% carbon black and graphite (or a similar metallic substance) have been added to increase electrical and thermal conductivity. The frictional heat that develops (especially at higher speeds) is dissipated better along the entire ski or snowboard base due to this thermal conductivity...it helps reduce the water film that can otherwise build up and create suction and drag. The improved electrical conductivity helps reduce static electricity build-up that attracts and holds dirt and pollutants on the base, also creating more drag.

 

The addition of graphite has been shown in tests to reduce friction and increase glide on snow by 20% or more over clear (non-graphite) p-tex bases in cold dry snow (under -13°F or -25°C), and by 15 to 20% more in warmer snow (over 23°F or -5°C) when humidity is 40% or above.

The drawback of Electra bases, however, is less water repellancy and both impact and abrasion resistance than that offered by clear sintered p-tex.

Electra-spec, double-sint, and triple-sint bases are a blend of clear sintered, colored sintered, and/or electra p-tex mixed together and reheated. While the cosmetic impact of these exotic recipes may be impressive, there is no performance advantage over standard sintered p-tex bases.

 

 

post #13 of 22

Here's some good info from a very interesting site on alpine snowboards:

Note the different wax absorption rates!

 

http://www.alpinecarving.com/boards.html


 

Base Material

 

Snowboards come with Ultra High Molecular Weight Polyethylene (UHMWPE) bases that are either sintered or extruded. Sintered bases are more porous, and as a result are better at absorbing and retaining wax. They also have longer polymer chains, which makes them more durable, but more expensive to repair. There are three major suppliers of snowboard base material:

IMS Plastics makes the P-Tex brand.

Isosport makes the Isospeed brand.

Crown Plastics makes the DuraSurf brand.

IMS Plastics was the first to patent a process to create a plastic material that can be easily bonded using epoxy, resulting in P-Tex, their brand of base material. However, base materially of any type is generically referred to as "P-Tex". Each company offers several different grades of base material with different durabilities and additives. Indium absorbs heat generated by friction between the base and snow, allowing the board to be "self cooling." The heat is carried away from the base and prevents the snow from melting into a layer of water that slows down the ride. Graphite conducts static electricity away from the base to lower friction, providing a small gain in speed on a race course. The P-Tex Electra base consists of about 11-12% graphite. However, graphite makes the base less durable and less able to absorb wax. Here are the specs for several grades of P-Tex.

 

Base Material Type Wax absorption mg/cm²

Abrasive volume loss relative to carbon steel

Comments
P-Tex 1000
extruded
1.3
70%
Transparent or colored polyethylene
P-Tex 2000
sintered
1.9
20%
Transparent or colored UHMWPE
P-Tex 2000 Ga/In
sintered
1.9
20%
P-Tex 2000 + thermo-active additives
P-Tex 2000 Electra
sintered
1.6
30%
P-Tex 2000 + carbon additives
P-Tex 4000
sintered
2.2
15%
Transparent or colored UHMWPE
P-Tex 4000 Ga/In
sintered
2.2
15%
P-Tex 4000 + thermo-active additives
P-Tex 4000 Electra
sintered
1.9
20%
P-Tex 4000 + carbon additives


So I followed some links:

 

links: www.durasurf.com -

www.ims-plastics.com  - this comes up as Gerit

 

Some might also be interested in this article I stumbled across:

find at: : http://www.crrel.usace.army.mil/sid/perovich/DKPpdf/CRSTskis.pdf


Temperature effects of black versus white polyethylene
bases for snow skis 

 

S.C. Colbecka,b,*, D.K. Perovichb
a 311 Goose Pond Road, Lyme, NH 03768, USA
bCRREL-ERDC, 72 Lyme Road, Hanover, NH 03755, USA


Received 22 March 2003; accepted 14 December 2003


 

 

post #14 of 22
Thread Starter 

OK, I think I've got it.  The Elan bases are sintered and the Fischer bases seem to be extruded.  It makes sense.  I'll just have to get used to it I guess.  I still like the Fischers best.

 

On a side note for Alpinord: We're  being dumped on right now.  I skied in at least a foot of new today and more is coming down.  It's supposed to last into the foreseeable future.  The skiing is finally good!

post #15 of 22

 

Quote:
Originally Posted by Posaune View Post

the Fischer bases seem to be extruded. 


They are *not* extruded.    

 

Extruded bases are *far* softer and less absorptive of wax; no mainstream manufacturer would use extruded bases on a top tier (i.e. full retail priced) adult ski.

post #16 of 22
Thread Starter 

 

Quote:
Originally Posted by comprex View Post

 

 


They are *not* extruded.    

 

Extruded bases are *far* softer and less absorptive of wax; no mainstream manufacturer would use extruded bases on a top tier (i.e. full retail priced) adult ski.

OK, I'll believe you.  Whatever they are, they're seemingly less porous, at least they look like it.  You can see the difference and feel it when you look at and touch the bases.  So whatever the difference is, it's apparent to the naked eye and to the touch.

post #17 of 22

 

Quote:
Originally Posted by Posaune View Post

 

 

OK, I'll believe you.  Whatever they are, they're seemingly less porous, at least they look like it.  You can see the difference and feel it when you look at and touch the bases.  So whatever the difference is, it's apparent to the naked eye and to the touch.

 

Sorry     was I being emphatic?    

 

I think I know what you mean though.   And I've been on mysteriously slow Fischers before,  including Atuas (and RX8s and WC4s).  

 

post #18 of 22

Some skis are just faster. Even when they are not perfectly tuned or waxed, I have skis that are noticeably faster than my fresh race-tuned skis. 

I truly believe that P-tex is not as uniform and consistent as we think.

post #19 of 22

P-tex is definitely not uniform, and there's way more then just few sorts of it. When I was still skiing, we were getting skis (xc skis) from Fischer racing service, and there was about 30 different P-tex which you could get on skis. Next to that there was endless count of different structures. Combination of both defined how well specific skis would perform on specific snow.

So in this particular case, it can be snow related, it can be structure, p-tex and few 100 other reasons, why Fischer's were slower then Elan's.

post #20 of 22

Science Shmience. 

 

It is really a combination of Karma and Mojo. 

 

Some (identical) skis have it; some don't.  Don't ask me why.  Just obey the golden rule. You don't want to come back as Elans.

post #21 of 22

Ski construction is probably the difference. Most skis with metal layers run faster.

post #22 of 22


 

Quote:
Originally Posted by Racer256 View Post

 

It is really a combination of Karma and Mojo. 

 

Some (identical) skis have it; some don't.  Don't ask me why. 


 

This is why all of the bIg names in racing spend countless hours choosing their skis for the upcoming season. And why they cherish the skis that run fast, turn well, and feel right.

 

Ask anyone of them if they have a favorite, and I bet that they all do.

 

Mike

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