Document ID: chunk:federal_register_of_legislation:F2018L01518:reg:60:p8
Version: federal_register_of_legislation:F2018L01518
Segment Type: reg
Provision Reference: reg 60 (pt 8/12)
Character Range: 39166–41953

per cent from the outer diameter as measured before the test.

6.3. Tread pattern of a tyre

6.3.1.  In order to be classified as a "special use tyre" a tyre shall have a block tread pattern in which the blocks are larger and more widely spaced than for normal tyres and have the following characteristics:

                  (a) A tread depth ≥ 11 mm

                  (b) A void-to-fill ratio ≥ 35 per cent

6.3.2. In order to be classified as a "professional off-road tyre", a tyre shall have all of the following characteristics:

                  (a) A tread depth ≥ 11 mm;

(b) A void-to-fill ratio ≥ 35 per cent

(c) A maximum speed rating of ≤ Q."

6.3.3. Tread-wear indicators

6.3.3.1. The tyre shall include not less than six transverse rows of wear indicators, approximately equally spaced and situated in the principal grooves of the tread.  The tread-wear indicators shall be such that they cannot be confused with the rubber ridges between the ribs or blocks of the tread.

6.3.3.2. However, in the case of tyres of dimensions appropriate for mounting on rims of a nominal diameter of 12 or less, four rows of tread-wear indicators shall be accepted.

6.3.3.3. The tread-wear indicators  must  provide  a means of  indicating,  with  a  tolerance of +0.60/-0.00 mm, when the tread grooves are no longer more than 1.6 mm deep.

6.3.3.4. The height of tread-wear indicators is determined by measuring the difference between the depth, from the tread's surface, to the top of the tread-wear indicator and to the bottom of the tread groove close to the slope at the base of the tread-wear indicator.

7. Modifications of the type of tyre and extension of approval

7.1. Every modification of the type of tyre shall be notified to the Administrative Department which approved the type of pneumatic tyre.  The department may then either:

7.1.1. Consider that the modifications made are unlikely to have an appreciable adverse effect and that in any case, the tyre still complies with the requirements; or

7.1.2. Require a further test report from the Technical Service responsible for conducting the tests.

7.2. A modification of the tread pattern of the tyre shall not be considered to necessitate a repetition of the tests prescribed in paragraph 6. of this Regulation.

7.3. Confirmation or refusal of approval, specifying the alterations, shall be communicated by the procedure specified in paragraph 5.3. above to the Parties to the Agreement which apply this Regulation.7.4.              The Competent Authority issuing the extension of approval shall assign a series number  for  such  an extension  and   inform  thereof  the  other  Parties   to   the 1958 Agreement applying this Regulation by means of a communication form conforming to the model in Annex 1 to