Overview
ISO 8705:2005 - “Mopeds - Measurement method for location of centre of gravity” specifies a standardized laboratory procedure to determine the location of the centre of gravity (CoG) for two‑wheeled mopeds and for the moped/rider combination. The standard describes axis systems, required measurement conditions, instruments, and step‑by‑step procedures along the x, y and z axes. It applies to two‑wheeled mopeds; alternative methods are permitted only if equivalence of results is demonstrated.
Key topics and technical requirements
- Scope and purpose: Measurement of CoG of the moped and moped + rider (test dummy or equivalent) as one element of kinetic characteristics relevant to stability. Results alone are not a full stability assessment.
- Axis systems: Defines a moped‑fixed right‑hand orthogonal system (x forward, y to rider’s left, z upward) and an Earth‑fixed system (X, Y horizontal; Z upward).
- Measurement conditions: Specified vehicle condition (clean, no deformation), fuel/oil/cooling levels per manual, tyre pressure, tools in storage positions, suspension fixed, front wheel aligned. For rider tests a 73.4 kg test dummy (49 CFR Part 572, subpart B, or equivalent) or human subject is used; rider posture and seating position are defined and recorded.
- Measuring instruments and tolerances:
- Precision square level: 0.1 mm/m
- Steel tape: specified tolerance formula
- Angle gauge: 0.1° resolution
- Weighing scales: 0.1 kg resolution
- Platform: rigid, lightweight; supports, knife edge (edge roundness
