Overview
ISO 1102:2001 specifies the characteristics and interchangeability requirements for 50 mm drawbar eyes used on commercial road vehicles and trailers with a maximum total mass above 3.5 t. The standard defines identification, mating requirements with C 50 drawbar couplings, dimensional limits, classification options (D 50-A to D 50-D) and mandatory test references to ensure safe, reliable mechanical connections between towing vehicles and trailers.
Key topics and technical requirements
- Scope and identification
- Applies to mechanical drawbar eye connections for commercial vehicles >3.5 t.
- Marking/identification examples: Drawbar eye ISO 1102 D 50 or Drawbar eye ISO 1102 D 50-C for classified types.
- Interchangeability and mating
- D 50 drawbar eyes are intended to be used with C 50 drawbar couplings and must not rotate axially.
- Dimensions
- Characteristic dimensions for non-classified D 50 eyes (from the standard) include maximum values such as h ≤ 80 mm and b ≤ 62 mm (see Figure 1 / Table 1).
- Classified variants (D 50-A to D 50-D) have specific dimensional drawings and tolerances (e.g., D 50-A characteristic dims shown in Table 2).
- Drawbar eyes fitted with slotted or non-slotted sleeves must follow the sleeve dimensions shown in the standard (Figures 2–3).
- Performance / characteristic values
- Minimum characteristic load and mass values are defined per class. Examples from Table 3:
- D 50-A: 130, 90, 1 000, 30 (units as listed in the standard)
- D 50-C: 190, 120, 1 000, 50
- D 50-D: 190, 130, 1 000, 75
- Testing
- All 50 mm drawbar eyes shall be tested in accordance with ISO 8718 and/or ISO 12357 (strength tests for drawbar couplings and eyes).
Applications and who uses this standard
- Vehicle and trailer OEMs designing drawbar couplings and mounting interfaces
- Component manufacturers producing 50 mm drawbar eyes, sleeves and sockets
- Test laboratories and certification bodies performing strength and interchangeability tests
- Fleet operators, maintenance engineers and procurement teams ensuring compatibility and safe coupling across trailers and towing vehicles
- Regulators and standards committees responsible for vehicle equipment compliance
Benefits include assured interchangeability, improved operational safety, simplified procurement and reduced downtime when coupling trailers to different towing vehicles.
Related standards
- ISO 8718 - Drawbar couplings and eyes (strength tests)
- ISO 12357 - Drawbar couplings and eyes for rigid drawbars (strength tests)
- ISO 3584 - Drawbar couplings - Interchangeability
- ISO 11406 / ISO 11407 - Mechanical coupling and mounting dimensions for towing vehicles and trailers
Keywords: ISO 1102:2001, 50 mm drawbar eye, drawbar coupling, interchangeability, commercial road vehicles, D 50, drawbar eye dimensions, coupling standards.
