Study evaluating the validity of the current recommendation in Annex 3 Appendix 5 for sandpaper surface replacement interval based on running distance by examining test results exceeding 20,000 km. Testing nine consecutive runs on #80 grit sandpaper without replacement over 45,000 km total distance using new tyres for each run. Surface roughness measured by MPD and micro roughness showed no significant change and satisfied requirements in Paragraph 2.4.2.3. SRTT17S abrasion level remained above specification limits. Reproducibility of Abrasion Index was maintained when compared with Market Assessment results. Proposes extending replacement interval from 20,000 km to 30,000 km for 2-position drums and from 40,000 km to 60,000 km for 1-position drums.
Review of UN R186 for opportunities to improve wording.