Document ID: chunk:federal_register_of_legislation:F2018L01518:reg:60:p7
Version: federal_register_of_legislation:F2018L01518
Segment Type: reg
Provision Reference: reg 60 (pt 7/12)
Character Range: 36764–39376

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.

6.2.1.1. Where application is made for tyres identified by means of letter code "ZR" within the size designation and suitable for speeds over 300 km/h (see paragraph 4.1.15.), the above load/speed test is carried out on one tyre at conditions appropriate for the load index marked on the tyre and the speed symbol "Y". Another load/speed test must be carried out on a second sample of the same tyre type according to paragraph 2.6. of Annex 7 corresponding to the load and speed conditions specified as maximum by the tyre manufacturer (see paragraph 4.1.15. of this Regulation).

The second test may be carried out on the same tyre sample if the tyre manufacturer agrees.

6.2.1.2. Where application is made for the type approval of a "run flat system" the above load speed test is carried out on one tyre, inflated as per paragraph 1.2. of Annex 7, at the load and speed conditions marked on the tyre (see paragraph 3.1.6.1.).  Another load/speed test must be carried out on a second sample of the same tyre type as specified in paragraph 3. of Annex 7. The second test may be carried out on the same sample if the manufacturer agrees.

6.2.2. A tyre which after undergoing the load/speed test as specified in paragraph 2. of Annex 7 does not exhibit any tread separation, ply separation, cord separation, chunking or broken cords shall be deemed to have passed the test.

6.2.2.1. However, a tyre marked with the speed symbol "Y" which, after undergoing the relevant test, exhibits superficial blistering of the tyre tread caused by the specific test equipment and conditions, is deemed to have passed the test.

6.2.2.2. If a "run flat system" tyre which, after undergoing the test as specified in paragraph 3. of Annex 7, does not exhibit a change in the deflected section height, compared to the deflected section height at the start of the test, higher than 20 per cent and retains the tread connected to the two sidewalls, it is deemed to have passed the test.

6.2.3. The outer diameter of the tyre, measured six hours after the load/speed performance test as specified in paragraph 2. of Annex 7, must not differ by more than ±3.5 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