Overview
EN ISO 24266:2020 - Footwear - Test methods for whole shoe - Flexing durability specifies two laboratory test methods for determining the flexing durability of whole shoes. The standard defines how to repeatedly flex a complete shoe about its normal flexing line, how to prepare and condition samples, and how to record and report results. The two methods (Method A and Method B) are intentionally different and might not give comparable results; selection of a method should be agreed between parties or dictated by a product standard.
Keywords: EN ISO 24266:2020, flexing durability, footwear test methods, whole shoe flex testing, flexing cycles.
Key topics and technical requirements
- Scope limits
- Not applicable to whole shoes with heel height > 50 mm.
- Not applicable if thickness of the sole flexing area > 25 mm.
- Not applicable where flexing angle is less than 45° (per ISO 17707:2005, Clause 6).
- Principle
- Repeated flexing about the shoe’s flexing line; subjective inspection for damage after a set time or number of flexes.
- Method A (fixed parameters)
- Flexing speed: (140 ± 10) cycles per minute.
- Typical test run: 50 000 flexing cycles (other totals allowed by agreement).
- Flexing angle set to (30 ± 1)° for simulation of normal walking.
- Requires marking the flexing line (metatarsophalangeal joint position table provided).
- Method B (adjustable machine)
- Flexing angle adjustable from 0° to 55°; flexing frequency adjustable from 100 to 300 cycles/min.
- Uses a flexing last, adjustable sample holder, automatic stop after specified cycles, and an air blast to prevent overheating.
- Flexing last must allow flexing at the joint position; maximum flexible angle ≥ 50°.
- Apparatus and measurement
- Vernier calipers to accuracy better than 0.02 mm.
- Cutting tool and fixtures for Method B.
- Sampling & conditioning
- At least one pair per test; condition samples in standard atmosphere per ISO 18454 for ≥ 4 hours before and during testing.
- Results & reporting
- Record number of cycles or test duration and subjective assessment of damage; follow reporting requirements in the standard.
Applications and who uses it
- Footwear manufacturers for product development, durability verification and quality control.
- Independent test laboratories performing whole-shoe durability testing.
- Procurement teams and specification writers requiring validated durability data.
- R&D teams comparing materials, construction methods or sole units under controlled flexing.
- Regulatory/standards committees and certification bodies referencing whole-shoe flex performance.
Related standards
- ISO 18454 - Standard atmospheres for conditioning and testing of footwear (referenced for sample conditioning).
- ISO 17707:2005 - Referenced for flexing angle constraints (metatarsophalangeal joint position).
EN ISO 24266:2020 is a practical standard for standardized whole-shoe flex testing; choose Method A or B by agreement, and document test parameters clearly to ensure meaningful, comparable results.
