Abstract: Use as lubricants, especially for tractive drives, of ester compounds of the general formula I ##STR1## wherein Cb denotes a carboxylic grouping which may be monocarboxylic (MCb) of formula --O--CO--or --CO--O--, dicarboxylic (DiCb) of formula --O--CO--R.sub.4 --CO--O--or --CO--O--R.sub.4 --O--CO--, or tetracarboxylic (TCb) of formula --O--CO--R.sub.5 --CO--O--R.sub.6 --O--CO--R.sub.5 --CO--O--; R.sub.4 represents an optionally substituted alkylene or alkenylene group, a C.sub.5-10 cycloalkylene group, a di-(C.sub.5-10 cycloalkylene) group, or a C.sub.5-10 cycloalkenylene group; R.sub.5 represents an alkylene group and R.sub.6 represents a cycloalkylene group;each group R.sub.3 individually represents a C.sub.1-6 alkyl, C.sub.2-6 alkenyl, C.sub.3-20 mono- or polycycloalkyl group or a hydrogen atom; m and n are each 0 or 1;R.sub.1 represents an optionally substituted C.sub.4-10 tertiary alkyl group or an optionally substituted C.sub.3-8 cycloalkyl or C.sub.6-14 bicyclo or tricycloalkyl group; and R.sub.