Document ID: chunk:federal_register_of_legislation:F2018L01518:reg:60:p6
Version: federal_register_of_legislation:F2018L01518
Segment Type: reg
Provision Reference: reg 60 (pt 6/12)
Character Range: 34377–37023

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. 3.1.13.) symbol "A" or "U", 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 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, whereby the limits shall be rounded to the nearest mm:

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. 3.1.13.) symbol "A" or "U", the overall width of the tyre, in the lower area of the tyre, equals the nominal width of the rim on which the tyre is mounted, as shown by the manufacturer in the descriptive note, increased by 20 mm.

6.1.5. Tyre outer diameter specifications

 The outer diameter of a tyre must not be outside the values Dmin and Dmax obtained from the following formulae:
Dmin = d + 2 • Hmin
Dmax = d + 2 • Hmax
where:
Hmin = H • a rounded to the nearest mm
Hmax = H • b rounded to the nearest mm

6.1.5.1. For sizes listed in Annex 5 and for tyres identified by the "tyre to rim fitment configuration" (see paragraph 3.1.13.) symbol "A" or "U", the nominal section height H is equal to:

H = 0.5 (D-d), rounded to the nearest mm – for references see paragraph 6.1.2.1.

6.1.5.2. for other sizes, not listed in Annex 5, "H" and "d" are as defined in paragraph 6.1.2.1,

6.1.5.3. Coefficients "a" and "b" are respectively:

6.1.5.3.1. Coefficient "a" = 0.97

6.1.5.3.2. Coefficient "b" Radial, Run flat tyre  Diagonal and Bias Belted
for normal tyres  1.04    1.08
for special-use tyres  1.06      1.09

6.1.5.4. For snow tyres the outer diameter shall not exceed the following value

  Dmax,snow = 1.01 • Dmax  rounded to the nearest mm

where Dmax is the maximum outer diameter established in conformity with the above.

6.2. Load/speed performance test

6.2.1. The tyre shall undergo a load/speed performance test carried out by the procedure described in Annex 7 to this Regulation.