ISO 16231-2:2015

Overview

ISO 16231-2:2015 - "Self‑propelled agricultural machinery - Assessment of stability - Part 2" specifies accepted methods and test procedures to determine the static stability of ride‑on self‑propelled agricultural machines. The standard covers procedures to find the centre of gravity (COG) for un‑laden machines, methods to establish the COG for laden machines and machines with attachments, and procedures to determine the static overturning angle (SOA). It complements ISO 16231‑1 (Principles) and references ISO 789‑6 for COG test technique.

Key topics and technical requirements

• COG determination (un‑laden): Uses scales and support stands to measure axle loads while lifting one axle. Procedures reference wheel radii, wheel base and stand height. Practical requirements include locking suspensions (or inflating tyres to max pressure), allowing wheels on scales to rotate, and preferring steel wheels to reduce radius change.
• Measurement accuracy: Repeated weighing values must lie within 1.0% of the maximum measured load; calculated COG height deviation shall not exceed ±4% (raise wheel‑stand height if exceeded).
• COG for laden machines / attachments: Graphical and mathematical methods are provided to combine known masses and individual COGs (e.g., full grain tank plus header) to determine the combined COG without unsafe angled weighing.
• Static overturning angle (SOA): Methods to calculate SOA (lateral rollover, tip forward/rearward) are given for multiple configurations - machines with fixed and swivelling axles (with and without swivel limits), tracked machines, machines with locking devices or individual suspension, and those with body levelling systems.
• Supplementary material: Annexes include worked examples for COG and SOA calculations, a normative method for calculating RSSA, and an informative discussion of dynamic effects on rollover/tip‑over.

Applications and who uses it

ISO 16231‑2:2015 is intended for:

• OEMs and designers of tractors, harvesters and self‑propelled implements to assess and optimize static stability during design and pre‑production testing.
• Test laboratories and certification bodies performing stability assessments and type‑approval testing.
• Safety engineers and fleet managers assessing rollover/tip‑over risk for specific machine configurations and payloads.
• Researchers evaluating stability impacts of attachments, body levelling systems and load distributions.

Practical applications include COG determination for final‑assembly verification, evaluating worst‑case loaded conditions (e.g., full grain tank), and defining safe operating slopes or design changes to reduce rollover risk.

Related standards

• ISO 16231‑1 - Assessment of stability: Principles
• ISO 789‑6 - Agricultural tractors - Test procedures - Part 6: Centre of gravity
• Separate ROPS/self‑protective structure standards address protective structure requirements (not covered in this part).