Document ID: chunk:federal_register_of_legislation:F2018C00788:reg:60:p5
Version: federal_register_of_legislation:F2018C00788
Segment Type: reg
Provision Reference: reg 60 (pt 5/11)
Character Range: 35169–37987

measuring rim;

              S1 is the "nominal section width" (in mm) as shown on the  side wall of the tyre in the designation of the tyre as prescribed;

              A is the width (expressed in mm) of the measuring rim, as shown by the manufacturer in the descriptive note; 5[/]

         A1 is the width (expressed in mm) of the theoretical rim.

              A1 shall be taken to equal S1 multiplied by the factor x, as specified by the manufacturer, and K shall be taken to equal 0.4.

         6.1.1.2. However, for the types of tyres for which the designation is given in the first column of the tables in Annex 5 to this Regulation, the section width shall be that given opposite the tyre designation in these tables.

         6.1.1.3. However, for tyres identified by the "tyre to rim fitment configuration" (see para. 3.1.10.) symbol "A", K shall be taken equal to 0.6.

6.1.2.  Outer diameter of a tyre

6.1.2.1. The outer diameter of a tyre shall be calculated by the following formula:

         D = d + 2H

    where:

         D is the outer diameter expressed in mm

             d is the conventional number defined in paragraph 2.17.1.3. above, expressed in mm, 5/

         H is the nominal section height in mm, equal to:
         H = 0.01S1.Ra,

         S1 is the nominal section width in mm, and

         Ra is the nominal aspect ratio,

              all as shown on the side wall of the tyre in the tyre-size designation in conformity with the requirements of paragraph 3.4. above.

         6.1.2.2. However, for the types of tyres for which the designation is given in the first column of the tables of Annex 5 to this Regulation the outer diameter shall be that given opposite the "size" designation in these tables.

         6.1.2.3. However, for tyres identified by the "tyre to rim fitment configuration" (see para. 3.1.10.) symbol "A", the outer diameter shall be that specified in the tyre size designation as shown on the sidewall of the tyre.

6.1.3.  Method of measuring pneumatic tyres

         The dimensions of pneumatic tyres shall be measured by the procedure described in Annex 6 to this Regulation.

6.1.4.  Tyre section-width specifications

         6.1.4.1. The overall width of a tyre may be less than the section width determined pursuant to paragraph 6.1.1. above.

6.1.4.2. It may exceed that value by the following percentages:

6.1.4.2.1. in diagonal (bias-ply) tyres:  6 per cent;

6.1.4.2.2. in radial ply, run flat tyres:  4 per cent;

         6.1.4.2.3. in addition, if the tyre has special protective ribs (or bands), the figure as increased by the above tolerance may be exceeded by 8 mm.

         6.1.4.2.4. However, for tyres identified by the "tyre to rim fitment configuration" (see para. 3.1.10.) symbol "A", the overall width of the tyre, in