ISO 19447:2021 pdf download – Passenger car tyres — Method for measuring ice grip performance — Loaded new tyres.
4.4 Tyre preparation 4.4.1 General Fit each test tyre on an approved rim in accordance with ISO 4000-1 using conventional mounting methods. The rim width code shall not differ more than 0,5 from the measuring rim. If a commercialized rim is not available for the test vehicle, it will be acceptable to use a rim whose rim width code differs by 1,0 from the measuring rim width code. Ensure proper bead seating with the use of a suitable lubricant. Excessive use of lubricant should be avoided to prevent slipping of the tyre on the wheel rim. The studless tyres should be broken in prior to testing (at least 100 km on dry roads or with an equivalent method) to ensure stable performance and to remove spew, compound nodules or flash resulting from the moulding process. Studded tyres should be broken in prior to testing (at least 100 km on roads or with an equivalent method) to ensure correct fit of the studs and stable performance. In all cases, tyre designed tread depth and designed tread block or rib integrity shall not change significantly with breaking in, which means the pace and severity of the breaking in run needs to be carefully controlled to avoid such changes. When testing studded tyres, the stud protrusion shall be measured before each braking test according to the procedure described in 4.4.2. It is acceptable to recondition a test tyre before the braking test. The reconditioning may be performed to reach the stabilized performance level. It can be done, for example, by driving 5 km to 10 km on rough road surfaces or equivalent.
The tyre surface in contact with ice shall be cleaned before performing the test, removing snow and dirt. Tyre and wheel assemblies shall be conditioned at the ambient temperature (outdoor or indoor, depending on the test facility) at least two hours before they are fitted on the vehicle for tests. Tyre pressures shall then be adjusted to the values specified for the test. If a vehicle cannot accommodate both the reference and candidate tyres, a third (control) tyre may be used as an intermediate. First, test the control tyre versus the reference on a suitable vehicle, then test the candidate tyre versus the control tyre on the selected vehicle. 4.4.2 Stud protrusion measurement procedure The stud protrusion measurement shall be done under the test inflation pressure conditions. Figure 1 illustrates the stud protrusion device. It shall be equipped with a support plate (2) of 20 mm diameter and 12 mm diameter hole for the measurement head (1). The measurement head shall be pressed perpendicular to the tread surface with a force of 15 N to 20 N to trigger the measurement. The stud protrusion shall be measured from every test tyre, from 20 consecutive studs over the whole width of the tread and in circumferential direction, and at the same stud positions each time. Define in the test report whether tested with or without studs, and accordingly the stud type, name or main dimensions.