ISO 13326 pdf download.Test methods for measuring tyre uniformity
1 Scope
This International Standard specifies test methods carried out under controlled conditions for verifying the uniformity of tyres for passenger cars, commercial vehicles and motorcycles. NOTE — Lack of uniformity around a tyre produces variations in forces applied by the tyre to the vehicle and this influence is repeated with each revolution of the tyre. At the present state of the art, however, it is impossible to manufacture perfectly uniform tyres. A rigid control of the complete manufacturing process can only minimise the unavoidable imperfections of materials, components and processes affecting uniformity. Methods for measuring the geometrical run-out of the tyre in both radial and lateral directions are covered, as well as methods for measuring the following parameters: – radial force variation; – lateral force variation; – ply steer; – conicity. Not all of these measurements will necessarily be relevant in every situation. This International Standard does not include methods for measuring the static and the dynamic unbalance nor methods related to tyre-wheel assemblies. The test methods specified in this International Standard are not intended for the gradation of tyres or the definition of quality levels.
2 Normative references
The following standards contain provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the editions indicated were valid. All standards are subject to revisions and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent edition of the standards indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO 4000-1 :1 995, Passenger car tyres and rims — Part 1 : Tyres (metric series). ISO 4000-2:1 994, Passenger car tyres and rims — Part 2: Rims . ISO 4209-1 :1 993, Truck and bus tyres and rims (metric series) — Part 1 : Tyres .
3 Definitions
For the purposes of this International Standard, the definitions given in ISO 4223-1 , ISO 8855, VIM and the following apply. NOTES 1 See figure 1 for the axis reference system. 2 Also refer ISO 4000-1 , ISO 4000-2, ISO 4209-1 , ISO 4209-2, ISO 4249-1 , ISO 4249-2, ISO 4249-3, ISO 5751 -1 , ISO 5751 -2, ISO 6054-1 and ISO 6054-2. 3.1 uniformity state in which any characteristic of the tyre is constant in phase and magnitude in both static and dynamic conditions around the circumference NOTE — Uniformity is concerned with axis symmetry of mass distribution, geometry and forces generated when the solid is in motion. Lack of uniformity in a tyre, when it is rotating around its axis, causes variations of forces, which may vary with the angular speed and are applied to the said axis. 3.2 peak to peak (total) difference between the maximum and the minimum values of measurement signal, within a specified bandwidth, during one revolution 3.3 first harmonic peak to peak amplitude of the fundamental frequency component of the Fourier transform representing the variation NOTE — Its frequency is equal to the frequency of rotation. 3.4 second (and higher order) harmonic peak to peak amplitude of the second (or higher order) frequency component of the Fourier transform representing the variation 3.6 Geometry 3.6.1 tyre radial run-out variation of the tyre radius measured perpendicularly to the spin axis on a circumference along the tread surface, excluding the influence of the various grooves and vents located on the tread, in millimetres 3.6.2 tyre lateral run-out variation of the distance from a fixed reference plane, normal to the spin axis, of a given tyre sidewall at a given distance from said axis, excluding the influence of the lettering and other markings on the sidewall, in millimetres 3.6.3 test rim radial run-out variation of the wheel radius measured perpendicularly to the spin axis on a circumference along the bead seat, in millimetres NOTE — It is measured separately for each bead seat. 3.6.4 test rim lateral run-out variation of the distance from a fixed reference plane, perpendicular to the spin axis, of the inside vertical portion of the rim flange at a given distance from said axis, in millimetres NOTE — It is measured separately for each rim flange.