The structures and the wear data of 47 different organic compounds as lubricant base oils were included in a comparative molecular field analysis (CoMFA) and comparative molecular similarity index analysis (CoMSIA)quantitative structure tribo-ability relationship (QSTR) model. CoMFA- and CoMSIA-QSTR models illustrate good accuracy, robustness, and predictability, with the latter more accurate than the former. CoMFAQSTR with both steric and electrostatic fields: R2=0. 958, R2 (LOO)=0.958, and q2=0.625; with only a steric field: R2=0.987, R2 (LOO...