Overview
ISO 6695:2015 - "Cycles - Pedal axle and crank assembly with square end fitting - Assembly dimensions" specifies the assembly dimensions and tolerances for cranks mounted on bottom‑bracket spindles with square end fittings. The standard defines geometric features, reference planes and dimensional limits (given in millimetres) to ensure correct fit, safe operation and interchangeability of crank and spindle components.
Key topics and requirements
- Scope: Dimensions for assembly of cranks on bottom‑bracket spindles with square end fittings are defined and illustrated.
- Illustrations and tables: Figure 1 (multiple views and cross‑sections) and Table 1 provide the dimensional layouts and tolerances that manufacturers must follow.
- Dimensional details: Includes spindle end geometries (square end, external/internal thread variants, cross‑section), crank fitting details, assembly clearances and reference planes.
- Tolerances and threads: Table 1 lists dimensional tolerances (metric, mm) and common thread specifications shown in the document extract (examples include M10×1.25, M8×1, M22×1).
- Assembly requirements: Notes include assembly practice such as final tightening to the supplier’s recommended torque and specification of wedge/angle parameters (e.g., half wedge angle β1/2).
- Revision history: The 2015 edition replaces ISO 6695:1991 and adds revised illustrations, front view of cranks, updated dimensions/tolerances and new angle specifications.
Applications and who uses it
- Bicycle OEMs and component manufacturers: Ensure cranksets and bottom‑bracket spindles are dimensionally compatible and manufacturable to tolerance.
- Design and engineering teams: Use the standard for CAD modelling, mechanical interface design and tolerance analysis.
- Quality control and test labs: Verify parts meet specified assembly dimensions and thread/tolerance requirements.
- Aftermarket and replacement part suppliers: Provide compatible cranks and spindles that interchange safely with existing square‑taper systems.
- Service technicians and assembly lines: Follow torque and assembly guidance to achieve reliable, safe crank retention.
Practical value
- Ensures interchangeability between crank and spindle components across suppliers.
- Reduces risk of premature wear, failure or unsafe assembly caused by incorrect dimensions or tolerances.
- Simplifies supply chain compatibility and aftermarket replacement strategies.
Related standards
- Developed by ISO/TC 149 (Cycles). This standard complements other cycle‑related ISO documents covering safety, performance and component interfaces; consult ISO/TC 149 publications for broader bicycle standardization context.
Keywords: ISO 6695:2015, pedal axle, crank assembly, square end fitting, bottom bracket spindle, assembly dimensions, bicycle crank, crankset compatibility, ISO cycles standard.
