ISO 8755:2001

Overview

ISO 8755:2001 - Commercial road vehicles - 40 mm drawbar eye - Interchangeability defines the dimensional and performance characteristics required for 40 mm drawbar eyes to ensure safe interchangeability of coupling components between towing vehicles and trailers. The standard applies to mechanical connections for commercial vehicles and trailers with a maximum total mass above 3.5 t. It ensures compatibility between drawbar eyes and corresponding C 40 drawbar couplings, preventing axial rotation and standardizing identification.

Key topics and requirements

• Scope and applicability
  • Covers 40 mm drawbar eyes used on commercial road vehicles and trailers > 3.5 t.
• Designation and marking
  • Drawbar eyes are identified by reference to the standard and code (e.g., Drawbar eye ISO 8755 D 40, or D 40-C for classified types).
• Dimensional requirements
  • Characteristic dimensions are given (figures and tables). Example limits include maximum characteristic dimensions for non-classified D 40 (see ISO text for exact values).
  • Drawbar eyes with sleeves must meet specific sleeve dimensions (slotted or non‑slotted).
• Classes and characteristic values
  • Classified types D 40-A, D 40-B, D 40-C have defined dimensional variants and minimum characteristic performance values (Table 3 in the standard), with D 40‑C having higher vertical load capability.
• Mechanical performance and testing
  • All 40 mm drawbar eyes must be tested according to ISO 8718 or ISO 12357 (strength tests for hinged and rigid drawbars respectively).
• Interchangeability requirements
  • Specifies that D 40 eyes must mate with C 40 couplings and restrict axial rotation to ensure safe, interchangeable coupling.

Applications and users

• Manufacturers of drawbar eyes, drawbar couplings and trailer components use ISO 8755:2001 to design parts that are dimensionally compatible and certifiable for international markets.
• OEMs and trailer builders adopt the standard to ensure replacement and aftermarket parts fit consistently and safely.
• Testing laboratories and certification bodies apply the specified strength tests and verification criteria.
• Fleet operators and maintenance shops rely on the standard for correct part selection, safe replacements and compliance with interoperability requirements.
• Regulators and homologation authorities reference the standard when setting vehicle coupling safety requirements.

Related standards

• ISO 8718 - Drawbar couplings and eyes (strength tests, hinged drawbars)
• ISO 12357 - Drawbar couplings and eyes (strength tests, rigid drawbars)
• ISO 3584 - Drawbar couplings - Interchangeability
• ISO 11406 / ISO 11407 - Operating clearance and mechanical coupling interchangeability for specific trailer/towing arrangements

ISO 8755:2001 is essential for ensuring safety, interchangeability and international compatibility of 40 mm drawbar eye couplings used on commercial road vehicles.