Standards Development

Scope

This ISO standard applies to heavy vehicles—that is, to commercial vehicles and buses as defined in ISO 3833—that are covered by the categories M3, N1, N2, N3, O3, and O4 of ECE and EC vehicle regulations. These categories pertain to trucks and trailers with maximum weights above 3,5 tonnes and to buses with maximum weights above 5 tonnes.

Vehicle suspension kinematic and compliance (K&C) properties that impact vehicle stability and dynamic behaviour are described in this standard and common methods of measurement are outlined. These methods are applicable to heavy vehicles. The measurements are performed on a single unit and typically one or two axles at a time.

This standard will define or reference the key suspension kinematic and compliance parameters necessary for characterizing and simulating vehicle suspension performance. These parameters also provide system-level descriptions of quasi-static behaviour that can be cascaded into subsystem and component performance targets. The suspension variables required for determining suspension characterization of one vehicle end, i.e. for a single axle or for multiple axles inter-related through suspension configuration (for example walking-beam), are provided. Metrics pertaining to the chassis connection between the front and rear suspensions are not included. Some typical methods of measurement will be discussed, however detail on how the measurements are executed is not within the scope of this standard

Purpose

This International Standard defines the common suspension kinematic and compliance properties of suspensions that relate to the change in orientation of the road wheel and tyre to the road surface as a result of, and relative to, forces, moments, and displacements input to the tyre contact patches. The forces, moments, and displacements are intended to reflect those encountered in real-world manoeuvres. Characterization of these properties is essential to modelling and analyzing the ride and handling behaviour of road vehicles as the motion of the tyre contact patch relative to the sprung mass is determined by both the sprung mass to tyre orientation and the tyre to road surface orientation.