Abstract Laboratory tests to evaluate piston ring and cylinder liner materials for their friction and wear behavior in realistic engine oils are describe to support the development of new standard test methods. A ring segment was tested against a flat specimen of gray cast iron typical o cylinder liners. A wide range of lubricants including Jet A aviation fuel, mineral oil, and a new and engine-aged, fully formulated 15W4 heavy duty oil were used to evaluate the sensitivity of the tests to lubricant condition. Test temperatures ranged from 25 to 100 8C. A steppe load procedure was used to evaluate friction behavior using a run-in ring segment. At 100 8C, all lubricants showed boundary lubricatio behavior, however, differences among the lubricants could be detected. Wear tests were carried out at 240 N for 6 h at 100 8C with new rin segments. The extent of wear was measured by weight loss, wear volume and wear depth using a geometric model that takes into accoun compound curvatures before and after testing. Wear volume by weight loss compared well with profilometry. Laboratory test results ar compared to engine wear rates.