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Comparison of Ski Dimensions for Manufactured Skis

by Jed Simpson
(forum login: hose-man)

November 11, 2005

Disclaimer: Contributed articles express the views of the author, not necessarily the views of SkiBuilders.com.  SkiBuilders.com accepts no liability for the content of this document, or for the consequences of any actions taken on the basis of the information provided.

Overview

This article studies trends in ski dimensions for manufactured skis.  Data was compiled from many manufacturers.  The results presented here can be used as a guide for designing skis.

So, What's the Problem?

Let's face it, ski design as most of us SkiBuilders have experienced is a complicated process.  A builder has to consider what materials to use, the profile of the core, the appropriate amount of camber (if there is such a thing), and, of course, the shape of the ski.  All these design issues can be complicated, and even worse, they can be coupled -- changing one aspect of a design can drastically affect something else. 

To help clear some of the smoke, I decided to compare and study ski dimensions for manufactured skis.  The motivation to do this came when I was trying to decide how much narrower the tail of a ski I was designing should be compared to the tip.   I conjectured there was probably some rule of thumb for this so I started studying existing skis.  I looked at websites and read gear guides, but at some point I was so overwhelmed by the volume of information, and I felt the need to compile it into a more manageable format and present it in hopes that it will be useful.

I started by collecting tons of data and archiving it in MS Excel.  The first resource was from the SKIING Magazine’s Gear Guide because it seemed very complete.  The review even listed side-cut geometry for skis.  Many of the manufacturer’s websites don’t even list side-cut info, so this was valuable information.  Afterwards, I consulted Couloir Magazine’s Gear Guide.  To complete my list, I filled in the missing models from the manufacturer’s websites and added some smaller companies listed on SkiBuilders.com (see the links page).  Additionally, I included some skis build by the Kams and Kelvin.

To help simplify this endeavor I limited my data collection to mid-fats and fats.  These were the shapes of skis I wanted to design and build.  Specifically, I targeted greater-than 80mm waist skis, but the ski mags had some all terrain type skis which were down in the 70mm range which I included for reference.

After some work, I ended up with a list of 104 skis.  The numbers listed in the Excel spreadsheet didn't really tell me much at first so I started sorting the data.  However, the volume of information was still too vast and further analysis was required.  Here's the list (you can download the Excel file by clicking here; the data set available here has a few of my formulas applied.   These display the tip/tail taper, and the side-cut depth.   Once you’ve downloaded it you can apply any formulas you’d like to view even more potentially useless data.):

BRAND

MODEL

CATEGORY

TIP

WAIST

TAIL

RADIUS (M)

AK

Pro Mountain

Not in SKIING mag reviews

110

71

100

 

AK

No Ka Oi

Not in SKIING mag reviews

117

78

107

 

AK

King Salmon

Not in SKIING mag reviews

125

94

115

 

Atomic

Kontega

Telemark

108

78

102

 

Atomic

Tacora

Telemark

117

80

104

 

Atomic

Kongur

Telemark

116

84

108

 

Atomic

Janak

Telemark

123

99

115

 

Atomic

Pimp

Big Mountain Pro/Custom

127

99

118

30

Black Diamond

Ethic

Telemark

108

79

98

 

Black Diamond

Crossbow

Telemark

114

83

104

 

Black Diamond

Havoc

Telemark

122

88

114

22.5

Black Diamond

Verdict

Telemark

124

98

114

 

Blizzard

Sigma Titan Eight

Big Mountain Expert

116

80

106

16

Donek

Donek

Telemark

116

78

108

 

DP (Drake Powderworks)

Cassair

Not in SKIING mag reviews

116

80

104

 

DP (Drake Powderworks)

Wailer

Not in SKIING mag reviews

126

95

113

 

DP (Drake Powderworks)

Lotus

Not in SKIING mag reviews

142

120

127

 

Dynafit

FR 10.0

Not in SKIING mag reviews

118

88

110

 

Dynastar

Legend 8000

All Terrain Expert

116

79

102

21

Dynastar

Legend 8800

Big Mountain Expert

117

89

110

27

Dynastar

Legend Pro Rider

Big Mountain Pro/Custom

124

97

116

32

Elan

M 666

All Terrain Expert

116

76

102

17.9

Elan

Magfire 12

"One Ski Quiver"

116

76

102

17.9

Elan

M 777

Big Mountain Expert

117

87

107

26.1

Elan

M 999

Big Mountain Pro/Custom

129

99

119

31.3

Faction

Dillinger

Not in SKIING mag reviews

120

86

108

 

Faction

Wednesday

Not in SKIING mag reviews

122

88

110

 

Faction

3.Zero

Not in SKIING mag reviews

125

95

115

 

Fischer

AMC 76

"One Ski Quiver"

120

76

106

16

Fischer

AMC 79

All Terrain Expert

116

79

109

18

Fischer

T-Stix 88

Telemark

124

88

112

18

Fischer

Kehua

Not in SKIING mag reviews

127

92

115

20

Fischer

T-Stix 92

Telemark

127

92

115

20

Fischer

Atua

Big Mountain Expert

129

96

119

22

Fischer

T-Stix 96

Telemark

131

96

119

22

Fischer

Watea

Big Mountain Pro/Custom

134

101

124

25

Fischer

Prohete

Not in SKIING mag reviews

135

106

123

28

G3

Ticket

Telemark

120

81

109

 

G3

Baron

Telemark

116

81

104

 

G3

Siren

Telemark

121

88

109

 

G3

Reverend

Telemark

126

93

114

 

Goode

Carbon 82

Not in SKIING mag reviews

119

82

109

 

Goode

Carbon 95

Not in SKIING mag reviews

125

95

113

 

Goode

Carbon 116

Not in SKIING mag reviews

138

116

124

 

Head

Monster I.M 77

All Terrain Expert

119

77

104

17.9

Head

monster I.M 88

Big Mountain Expert

126

88

112

21.7

K2

Shuksan

Not in SKIING mag reviews

117

78

105

 

K2

Apache Recon

All Terrain Expert

119

78

105

15.8

K2

Piste Pipe

Telemark

118

85

109

 

K2

Apache Outlaw

Big Mountain Expert

124

88

111

19

K2

Work Stinx

Telemark

124

88

111

 

K2

Hippy Stinx

Telemark

125

95

118

 

K2

Seth Viscious

Big Mountain Pro/Custom

130

98

118

21

K2

Apache Chief

Big Mountain Expert

131

98

116

24

K2

Anti Piste

Telemark

131

98

116

 

K2

Made'n AK

Not in SKIING mag reviews

137

108

127

 

Karhu

Grizzly

Telemark

112

75

101

 

Karhu

Agent

Telemark

110

80

103

 

Karhu

Kodiak

Telemark

117

80

105

 

Karhu

Jak

Telemark

124

90

113

 

Karhu

Jak Team Edition

Telemark

134

100

125

 

Karhu

PFD

Telemark

139

110

137

 

Masurao

Shin Shin

Not in SKIING mag reviews

116

82

105

 

Masurao

Shinsetsu

Not in SKIING mag reviews

122

82

109

 

Movement

Thunder

Not in SKIING mag reviews

120

87

109

 

Movement

Gladiator

Not in SKIING mag reviews

125

92

113

 

Nordica

Hot Rod Modified

All Terrain Expert

119

74

104

15.8

PM

Bromodel

Not in SKIING mag reviews

125

99

114

 

Prior

Custom

Not in SKIING mag reviews

127

98

115

 

Prior

Doughboy

Not in SKIING mag reviews

147

107

122

 

Pure

Number 1

Telemark

120

90

109

 

Rossignol

Zenith 29

"One Ski Quiver"

126

74

105

14.8

Rossignol

Bandit B2

All Terrain Expert

116

78

105

16.6

Rossignol

DirtyBird

Not in SKIING mag reviews

116

78

105

 

Rossignol

Bandit B3

All Terrain Expert

120

83

110

17.3

Rossignol

PowderBird

Not in SKIING mag reviews

120

83

110

 

Rossignol

Bandit B4

Big Mountain Expert

122

94

112

23.6

Rossignol

SickBird

Not in SKIING mag reviews

128

98

121

 

Salomon

Scrambler Hot

All Terrain Expert

118

78

107

19.5

Salomon

Scrambler Custom

"One Ski Quiver"

124

85

114

17.6

Salomon

Teneighty Foil

Big Mountain Expert

124

87

115

20.4

Salomon

Gun (old Pocket Rocket)

Not in SKIING mag reviews

122

90

115

18

Salomon

Gun Lab

Big Mountain Pro/Custom

135

101

126

24.2

Ski Builders

Buttcracker

Telemark

123

90

110

 

Ski Builders

Klown Whacker

Telemark

130

97

124

 

Ski Builders

Ahmo

Telemark

130

97

120

 

Ski Builders

Kung Paoders

Telemark

124

98

114

 

Ski Builders

Tao

Telemark

118

104

114

 

Ski Builders

Ahma

Telemark

135

108

124

 

Ski Builders

Stiff Upper Lips

Telemark

126

109

116

 

Ski Builders

The Shit

Telemark

128

111

118

 

Ski Builders

White

Telemark

140

115

130

 

Stockli

Stormrider XL

All Terrain Expert

116

75

102

20.8

Stockli

Stormrider Scott Schmidt

Big Mountain Expert

122

89

112

25.5

Voile

Carbon Surf

Telemark

126

89

116

 

Voile

Insane

Telemark

140

109

132

 

Volkl

Unlimited AC3

All Terrain Expert

116

74

102

18.1

Volkl

Unlimited AC4

"One Ski Quiver"

125

82

110

17.8

Volkl

Karma

Not in SKIING mag reviews

115

87

111

22.3

Volkl

T-Rock

Not in SKIING mag reviews

119

87

111

24.5

Volkl

Mantra

Big Mountain Expert

130

94

113

21

Volkl

Gotama

Big Mountain Pro/Custom

130

105

122

29.4

Additional columns of data were added.  For example, I divided the tail width by the tip width, then subtracted the result from one.  This gave me a usable measure for percentage of taper from tip-to-tail measurement.  Was this the data I was after?   Naturally this is where things started getting even more interesting.   I learned to set up a chart in Excel. I expected to see that as skis got wider they increased in taper.   This would help keep the tip up in the powder.  Here is what I saw:

There is really no rhyme or reason to the application of taper it seems.   Based on the figure, the only conclusion I can draw is that, with a few exceptions, the taper is between 5% and 13% from tip to tail.  But what about the exceptions?  The Karhu PFD and the Volkl Sumo are at opposite ends of the taper spectrum from the Prior Doughboy which all are in the Top 10 widest skis!.   Two of the skis from the gallery of this site are among those with the least taper as well.  (the Tao and the Klown Whacker)

What other conclusions can we draw?

The graph above shows how the tip and tail widths react to the trend of increasing widths underfoot.   Notice that the ratio of tip-to-waist width generally shrinks as the skis get wider.  The more important trend might just be in the lack of a clear trend.  The way that the tip and tail line jump up and down tells me that in any given waist width there is a ski with a lot of side-cut and one with less side-cut.   Maybe not from the same manufacturer, but they’re out there.    The industry has definitely not homogenized.   The ski that creates the pinch in the graph at about the 104mm mark on the x-axis is the SB TaoThe Shit and the Goode Carbon 116 are similarly straight and wide.   They are the next two pinches at 111mm and 116mm along the horizontal axis.  Naturally there are going to be some really straight wide skis and of course there are some inverse side-cut skis.

Here is the same data as above but with side-cut depth on the horizontal axis: 

The overall trend above shows what we all already know, side-cut usually decreases as width increases.

Most of the skis in the data set have side-cut depths from 10-15mm and the side-cut is generally deeper for narrower skis.

What have I figured out?

I learned that there aren’t many rules-of-thumb to go by in the ski industry.  I think that there are different strokes for different folk as far as ski technology goes, and each combination of geometry is probably just right for someone out there, but not everybody.  Some points:

  • The range for tip to tail taper is 5%-13%

  • The typical sidecut is 10mm-17mm

I was surprised to learn that even within the same ski category for the same brand there are significantly different geometries.  For instance, consider the side-cut radius.   Most manufacturers use the same tip/waist/tail dimensions for all lengths of one model of ski.   This results in a different turning radius for each length.   How can these ski’s perform similarly enough to be considered the same model?   Shouldn’t the radius, waist width and flex be maintained while varying the tip and tail dimensions?   Wouldn’t that make more sense?   Do you like how my conclusion paragraph is full of questions?   That sort of speaks for this entire research project.

While I don’t feel like I wasted my time on this project, I really didn’t get the resolution I was hoping for.   There are no hard and fast relationships between dimensions of skis.   I will likely return to this resource with each new ski design I create to compare it to what the industry is producing.

 

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