ISO 23365:2022

Overview

ISO 23365:2022 defines the properties and common measurement methods used to determine suspension kinematic and compliance (K&C) characteristics for heavy commercial vehicles and buses. It applies to vehicles covered by ECE/EC categories M3, N2, N3, O3, and O4 (trucks, trailers and buses above specified gross weights per ISO 3833). The standard specifies the key suspension variables needed to characterize and simulate suspension performance, typically measured on a single unit or on one or two axles at a time. It does not cover chassis connection metrics between front and rear suspensions, and it outlines methods rather than step‑by‑step measurement execution.

Key topics

• Reference systems and variables - vehicle geometry, motion variables, forces and moments.
• Steering geometry - steering ratio, Ackermann, camber, castor, steering‑axis offsets and scrub radius.
• Kinematics - ride track change, ride steer, camber and castor changes, roll‑induced effects and gradients.
• Compliances - longitudinal and lateral force compliances, camber/steer compliances, aligning‑moment compliances and windup effects.
• Ride and roll stiffness - ride rate, suspension ride rate, roll stiffness, auxiliary roll stiffness, tandem axle stiffnesses and tyre normal stiffness.
• Force reactions - anti‑squat/anti‑dive, jacking forces, and tandem axle load redistribution gradients.
• Measurement guidance and equipment - recommended measurement variables, instrumentation accuracy considerations and data presentation formats.
• Data presentation - standardized ways to report steering ratio, kinematic and compliance properties, stiffness and force reaction properties.

Practical applications

ISO 23365:2022 is practical for:

• Vehicle OEMs and suspension suppliers designing and validating heavy‑vehicle suspension systems.
• Vehicle dynamics engineers and simulation teams using standardized K&C parameters for handling, stability and ride simulations.
• Test laboratories and certification bodies conducting axle‑level characterization and comparative testing.
• Controls and ADAS developers needing consistent suspension models for stability control tuning.
• Consultants and researchers analyzing heavy‑vehicle ride, roll and steering behavior.

Using ISO 23365 ensures consistent parameter definitions for model inputs, system‑level requirements and cascading subsystem/component targets, improving comparability across tests and suppliers.

Related standards

• ISO 3833 (vehicle categories and definitions) - referenced for vehicle class definitions.
• ECE/EC vehicle regulations - for applicability to M3, N2, N3, O3, O4 vehicle categories.

Keywords: ISO 23365, suspension kinematic and compliance, heavy commercial vehicles, bus suspension, vehicle dynamics, steering geometry, ride stiffness, roll stiffness, suspension parameters.