Document ID: chunk:federal_register_of_legislation:F2018C00788:reg:4:p2
Version: federal_register_of_legislation:F2018C00788
Segment Type: reg
Provision Reference: reg 4 (pt 2/4)
Character Range: 65966–68622

of the smooth wheel having 1.70 m + 1 per cent in diameter or less 30 km/h in the case of the smooth wheel having 2 m + 1 per cent in diameter;

2.5.3.  successive speed increments:  10 km/h;

2.5.4.  duration of test at each speed step except the last:  10 minutes;

2.5.5.  duration of test at last speed step:  20 minutes;

         2.5.6. maximum test speed:  prescribed maximum speed for the type of tyre, less 10 km/h in the case of the smooth wheel having 1.7 m + 1 per cent in diameter or equal to the prescribed maximum speed in the case of the smooth wheel having 2 m + 1 per cent in diameter.

         2.5.7. however, for tyres suitable for maximum speed of 300 km/h (speed symbol "Y"), the duration of the test is 20 minutes at the initial test speed step and 10 minutes at the last speed step.

         2.6. The procedure for the second test (see paragraph 6.2.1.1.), to assess the performance of a tyre suitable for speeds in excess of 300 km/h, shall be as follows:

         2.6.1. Apply to the test axle a load equal to 80 per cent of the maximum load rating associated with the maximum speed specified by the tyre manufacturer (see paragraph 4.1.15. of this Regulation).
         2.6.2. The test shall be run without interruptions in accordance with the following:

         2.6.2.1. Ten minutes to build up from zero to the maximum speed specified by the tyre manufacturer (see paragraph 4.1.15. of this Regulation).

    2.6.2.2. Five minutes at the maximum test speed.

         3. Procedure to asses the "flat tyre running mode" of "run flat system"

         3.1. Mount a new tyre on the test rim specified by the manufacturer pursuant to paragraphs 4.1.12. and 4.1.15. of this Regulation.

         3.2. Carry out the procedure as detailed in paragraphs 1.2. to 1.5. above with a test room temperature at 38 ºC + 3 ºC in relation to conditioning the tyre-and-wheel assembly as detailed in paragraph 1.4.

         3.3. Remove the valve insert and wait until the tyre deflates completely.

         3.4. Mount the tyre-and-wheel assembly to a test axle and press it against the outer surface of a smooth wheel 1.70 m ± 1 per cent or 2.0 m ± 1 per cent in diameter.

         3.5. Apply to the test axle a load equal to 65 per cent of the maximum load rating corresponding to the load capacity index of the tyre.

         3.6.  At the start of the test, measure the deflected section height (Z1).

         3.7.  During the test the temperature of the test room must be maintained at 38°C ± 3°C.

         3.8.  Carry the test through, without interruption in conformity with the following particulars:

         3.8.1. time taken