Overview - ISO 6266:2013 (Alpine skis - Fatigue indexes, cyclic loading test)
ISO 6266:2013 specifies a standardized laboratory method to determine the fatigue indexes of alpine skis - i.e., the permanent change in shape and stiffness after a bending cyclic loading test. The method quantifies two key parameters: bottom camber height and centre spring constant, after subjecting skis to repeated flexing and a defined recovery period. This standard is used to assess ski durability, compare designs, and support R&D and quality control.
Key topics and technical requirements
- Measured properties
- Bottom camber height (h): measured with a flat surface plate and dial indicator (accuracy ±0.03 mm).
- Centre spring constant (cM): measured per ISO 5902 (accuracy ±0.2 N/mm).
- Apparatus
- Bending machine with two adjustable supports (support spacing = nominal ski length − 280 mm) and support rolls ≈ 50 mm diameter.
- Clamping fixture with elastic rubber jaws (4 mm ±1 mm thickness; 40 mm width; hardness (95 ± 5) Shore A).
- Cycle counter on the push rod; measuring devices per ISO 5902 and a dial indicator for camber.
- Test parameters
- Sample size: 10 skis of the same type.
- Specified nominal ski lengths: 1 300 mm, 1 600 mm, 1 800 mm or 2 000 mm.
- Test loads by length: 1 300 mm → 250 N; 1 600 mm → 350 N; 1 800 mm/2 000 mm → 450 N.
- Stroke length s determined by s = F / cM (per original centre spring constant).
- Cyclic loading: 20 000 cycles at 2–3 Hz.
- Recovery time: 24 hours in a vertical, stress‑free position before final measurements.
- Temperatures
- Laboratory (A): 23 °C ± 2 °C.
- Cold chamber (B): −5 °C ± 2 °C.
- Results
- Fatigue indices Kh and Kc are percentage changes in camber height and centre spring constant; report mean of 10 tests.
- Visual inspection for damage (cracks, delamination, stress marks).
- Test report must reference ISO 6266 and include ski ID, test temperature, fatigue indices, observed damage, and deviations.
Applications and intended users
- Product development and R&D teams evaluating ski durability, stiffness retention, and design trade-offs.
- Quality assurance labs performing ski testing and batch comparisons.
- Manufacturers wanting standardized metrics for marketing claims or to comply with procurement/testing specifications.
- Research organizations studying material fatigue and performance under cyclic bending.
Related standards
- ISO 5902 - Alpine skis: determination of elastic properties (used for centre spring constant measurement).
- ISO 6289 - Skis: vocabulary (definitions such as camber height and nominal length).
Keywords: ISO 6266, alpine skis, fatigue indexes, cyclic loading test, camber height, centre spring constant, ski testing, bending machine, ski durability, material fatigue.
