Noise ranking of passenger car tyres. Results from road measurements, SPERoN modelling and drum measurements.

The rolling noise of a selection of passenger car tyres has been investigated using 3 different approaches:- CPX-measurements (17 tyres)- The use of the SPERoN model (34 tyres) - Laboratory drum measurements (15 tyres)The main object was to rank tyre/road noise levels of the tyres on typical Norwegian road surfaces and compare the ranking with levels on an ISO-surface.The main results show that the operational conditions for the three approaches are too different to make it possible to find any good correlations, based on linear regression of overall dB(A)-levels only. In addition, the spread in levels are rather small, which also could influence the correlation analysis. CPX-measurements are used for the ranking of 17 tyres, and the results show a variation of 2-4 dB(A) at 50 and 80 km/h, on a selection of dense and porous surfaces. The majority of the tyres (12 out of 17) has an average noise level, ± 0.5 dB(A), on the road surfaces included in the measurement program.Shore hardness and rolling resistance have been measured on 15 of the tyres and correlated to noise levels.It is recommended to include measurements on an ISO-track in future investigations, in order to be able to evaluate the effect of the new noise limits in the revised EU tyre noise directive for Norwegian conditions and the effect of noise labelling of tyres.

Oppdragsgivere: Statens vegvesen; Vegdirektoratet; Statens forurensningstilsyn;Norges forskningsråd