ASTM F498-19

Standard Test Method for Center Spring Constant and Spring Constant Balance of Alpine Skis

ABSTRACT
This test method covers the determination of center spring constant, forebody spring constant, and afterbody spring constant of Alpine skis. In addition, it covers a method for determination of the spring constant balance. The apparatuses shall be center spring constant equipment and forebody and afterbody spring constant equipment.
SCOPE
1.1 This test method covers the determination of center spring constant, forebody spring constant, and afterbody spring constant of Alpine skis. In addition, it covers a method for determination of the spring constant balance.  
1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.3 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 31-Oct-2019
• ICS: 97.220.20 - Winter sports equipment
• Technical Committee: F27 - Snow and Water Sports
• Drafting Committee: F27.30 - Skiing and Snowboarding Equipment

Relations

• Replaces: ASTM F498-12 - Standard Test Method for Center Spring Constant and Spring Constant Balance of Alpine Skis
• Effective Date: 01-Nov-2019
• Referred By: ASTM F504-05(2022) - Standard Test Method for Measuring the Quasi-Static Release Moments of Alpine Ski Bindings
• Effective Date: 01-Nov-2019

Overview

ASTM F498-19: Standard Test Method for Center Spring Constant and Spring Constant Balance of Alpine Skis provides a framework for accurately determining the bending stiffness and spring constant balance of Alpine skis. Developed by ASTM International, this standard outlines precise procedures and equipment requirements for measuring center, forebody, and afterbody spring constants. The resulting data are critical for manufacturers, quality control laboratories, and ski designers who need to ensure performance consistency, product safety, and regulatory compliance in the ski industry.

The standard is recognized internationally and was established in accordance with principles set forth by the World Trade Organization (WTO) on standardization. It emphasizes the importance of both reliable measurement techniques and adherence to best practices in safety and environmental responsibility.

Key Topics

• Spring Constant Determination: Methods for measuring the center, forebody, and afterbody spring constants of Alpine skis, quantifying each section's stiffness under a specified load.
• Spring Constant Balance: Calculation of the ratio between afterbody and forebody spring constants to evaluate balance and flex distribution along the ski.
• Precise Apparatus Setup: Requirements for supports, clamps, dynamometer, and measuring instruments to achieve accurate results.
• Reporting Requirements: Guidelines for documentation, including model identification, dimensions, ski size, and test results.
• Terminology: Clear definitions for terms such as spring constant, deflection, load, and the specific reference points (A, B, M) used in testing.

Applications

ASTM F498-19 serves a diverse range of practical purposes within the snow sports equipment industry:

• Ski Manufacturing: Enables manufacturers to standardize product performance and ensure uniform stiffness and flex pattern across ski models.
• Quality Assurance: Supports laboratory testing and verification of product claims regarding ski stiffness and handling characteristics.
• Product Development: Guides engineers and designers in tailoring ski flex profiles to specific performance criteria, improving ride quality and user experience.
• Market Compliance: Provides a referenced methodology for regulatory bodies and industry stakeholders to ensure that ski products meet international standards for safety and performance.
• Comparative Assessments: Facilitates objective comparison of different ski designs, assisting retailers, developers, and consumers in product selection.

By implementing the procedures defined in ASTM F498-19, organizations can improve consistency, enhance competitiveness, and bolster consumer confidence in Alpine skis.

Related Standards

Explore these related ASTM and international standards for snow ski performance and testing:

• ASTM F1069: Standard Specification for Design and Performance of Snow Ski Bindings
• ASTM F2040: Standard Specification for Helmets Used for Recreational Snow Sports
• ISO 5902: Alpine Skis - Determination of Bending Stiffness
• ISO 6289: Ski Terminology

These standards complement ASTM F498-19, providing comprehensive technical guidelines for the design, testing, and safety assessment of snow sports equipment.

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By adhering to ASTM F498-19, ski industry professionals can ensure rigorous testing, consistent quality, and heightened safety of Alpine skis, fostering innovation and reliability within snow sports markets.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: F498 − 19
Standard Test Method for
Center Spring Constant and Spring Constant Balance of
Alpine Skis
ThisstandardisissuedunderthefixeddesignationF498;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginal
adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.Asuperscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2.1.5 load F—theforceappliednormaltothesupportpoints
or the clamping plane, at points A, B, or M. The only
1.1 This test method covers the determination of center
component of load F is shown in Fig. 1.
springconstant,forebodyspringconstant,andafterbodyspring
constant of Alpine skis. In addition, it covers a method for 2.1.6 point A—the support point for the afterbody of the ski
when the center spring constant is measured or the load
determination of the spring constant balance.
application point when the afterbody spring constant is mea-
1.2 This standard does not purport to address all of the
sured.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro- 2.1.7 point B—the support point for the forebody of the ski
priate safety, health, and environmental practices and deter- when the center spring constant is measured or the load
mine the applicability of regulatory limitations prior to use. application point when the forebody spring constant is mea-
1.3 This international standard was developed in accor- sured.
dance with internationally recognized principles on standard-
2.1.8 point M—the load application point when the center
ization established in the Decision on Principles for the
spring constant is measured and the clamping point when the
Development of International Standards, Guides and Recom-
forebody spring constant or the afterbody spring constant is
mendations issued by the World Trade Organization Technical
measured.Itislocatedatthemidpointbetweenpoints Aand B.
Barriers to Trade (TBT) Committee.
2.1.9 ski size, x —the projected length with the ski body
pl
pressed flat against a plane surface, measured between the ski
2. Terminology
tail and the ski tip, commonly referred to as chord length. The
2.1 Definitions:
developed or material length is the length from tip to tail along
2.1.1 afterbody spring constant—the load, in newtons, re-
the bottom contour of the ski.
quired to deflect point A a distance of 1 cm.
2.1.10 spring constant—a measurement of the stiffness of a
F
A
ski in bending, expressed as a ratio of force to deflection.
C 5 (1)
A
f
m
2.1.11 spring constant balance—the ratio of afterbody
2.1.2 center spring constant—the load, in newtons, required
spring constant divided by forebody spring constant.
to deflect point M a distance of 1 cm.
C
A
F
B 5 (4)
M
C
C 5 (2)
M B
f
m
2.1.3 deflection f—the displacement of the ski under load F
3. Preparation of Apparatus
measuredatpoints A, B,or Mnormaltoalinebetweensupport
3.1 Center Spring Constant Equipment—Equip supports A
points or the clamping plane.
and B with low-friction rolls of 2.0 6 0.1 cm diameter.Apply
2.1.4 forebody spring constant—the load, in newtons, re-
the load with a dynamometer or calibrate the measurement of
quired to deflect point B a distance of 1 cm.
load with an accuracy of 60.5 N. Measure the deflection with
F
a suitable instrument with an accuracy of 60.005 cm. Apply
B
C 5 (3)
B
f
the load with a cylindrical contact ram having a radius of 1.0
B
6 0.1 cm and extending over the width of the ski.
3.2 Forebody and Afterbody Spring Constant Equipment—
This test method is under the jurisdiction of ASTM Committee F27 on Snow
andWater Sports and is the direct responsibility of Subcommittee F27.30 on Skiing
Provide a clamping fixture to grip the ski as a vise with a flat
and Snowboarding Equipment.
rigidjawandthre
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: F498 − 12 F498 − 19
Standard Test Method for
Center Spring Constant and Spring Constant Balance of
Alpine Skis
This standard is issued under the fixed designation F498; the number immediately following the designation indicates the year of original
adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This test method covers the determination of center spring constant, forebody spring constant, and afterbody spring constant
of Alpine skis. In addition, it covers a method for determination of the spring constant balance.
1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.3 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Terminology
2.1 Definitions:
2.1.1 afterbody spring constant—the load, in newtons, required to deflect point A a distance of 1 cm.
F
A
C 5 (1)
A
f
m
2.1.2 center spring constant—the load, in newtons, required to deflect point M a distance of 1 cm.
F
M
C 5 (2)
M
f
m
2.1.3 deflection f—the displacement of the ski under load F measured at points A, B, or M normal to a line between support
points or the clamping plane.
2.1.4 forebody spring constant—the load, in newtons, required to deflect point B a distance of 1 cm.
F
B
C 5 (3)
B
f
B
2.1.5 load F—the force applied normal to the support points or the clamping plane, at points A, B, or M. The only component
of load F is shown in Fig. 1.
2.1.6 point A—the support point for the afterbody of the ski when the center spring constant is measured or the load application
point when the afterbody spring constant is measured.
2.1.7 point B—the support point for the forebody of the ski when the center spring constant is measured or the load application
point when the forebody spring constant is measured.
2.1.8 point M—the load application point when the center spring constant is measured and the clamping point when the
forebody spring constant or the afterbody spring constant is measured. It is located at the midpoint between points A and B.
2.1.9 ski size, x —the projected length with the ski body pressed flat against a plane surface, measured between the ski tail and
pl
the ski tip, commonly referred to as chord length. The developed or material length is the length from tip to tail along the bottom
contour of the ski.
2.1.10 spring constant—a measurement of the stiffness of a ski in bending, expressed as a ratio of force to deflection.
This test method is under the jurisdiction of ASTM Committee F27 on Snow Skiingand Water Sports and is the direct responsibility of Subcommittee F27.30 on
SkisSkiing and BootsSnowboarding Equipment.
Current edition approved March 1, 2012Nov. 1, 2019. Published March 2012December 2019. Originally approved in 1977. Last previous edition approved in 20062012
as F498 – 77 (2006).F498 – 12. DOI: 10.1520/F0498-12.10.1520/F0498-19.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F498 − 19
FIG. 1 Physical Dimensions of Alpine Ski
2.1.11 spring constant balance—the ratio of afterbody spring constant divided by forebody spring constant.
C
A
B 5 (4)
C
B
3. Preparation of Apparatus
3.1 Center Spring Constant Equ
...