Can CPX method evaluate truck tyre noise ? A first approach using standardized light truck test tyre

The CPX method is an efficient tool for assessing and comparing road surface acoustic properties. The ISO 11819-2 standard recommends the use of two reference test tyres, a standardized one for representing the effect of light vehicles (P1), and a second one representative of heavy vehicle noise emission (H1). However, this latter is not anymore available on the market. The purpose of the present experiment is to test the relevance of an alternative candidate, a standardized tyre for light trucks (SRTT-C2). The first step was to check if the test tyre compares the pavement effect in a reliable and consistent way. Compared to the light vehicle tyre, a similar but not entirely identical effect is expected. CPX measurements were performed on 10 different surfaces on a test track, at different speeds ranging from 50 to 110 km/h. Three test tyres were used: P1, H1 and SRTT-C2. The latter was tested in two configurations, one with the pressure required in the ISO standard, and the other in a deflated state to obtain a footprint similar to that of a more realistic load for this type of tyre. The paper presents and discusses the main results.