Laboratory Alignment Procedure for Improving Reproducibility of Tyre Wet Grip Measurement

Abstract

Korea and EU governments are running the tyre labelling system from 2012. All tyres sold in Korea have to carry a label displaying information about two performance criteria such as rolling resistance and wet grip. The rolling resistance of tyres determines their fuel efficiency grading and the wet grip of tyres determines their braking safety grading. Measurement of rolling resistance and wet grip must be reproducible; tests on the same tyres in different laboratories must produce the same results in order to ensure a fair comparison between tyres from different suppliers. In addition, a good reproducibility of testing results prevents market surveillance authorities from obtaining different results from those of the suppliers when testing the same tyres. The laboratory alignment procedure of rolling resistance was developed and published as an EU Commission Regulation No. 1235 in 2011. But the laboratory alignment procedure of wet grip has not developed yet. So there are a lot of differences of wet grip test results among the test laboratories in the world. The proposed new procedure for the alignment of test laboratories with regard to the measurement of tyre wet grip can improve the reproducibility of the wet grip testing results. The proposed wet grip laboratory alignment procedure was verified through five laboratory alignment tests between KATECH and five test laboratories in the world.