Experimental investigations have been made using an apparatus specially built to study lubrication combined squeezing and sliding. In this investigation nine different lubricating greases and two base oils have been tested. The results are presented as a critical sliding velocity above which asperity contact occurs. The squeeze (normal) velocity was 0.2 m/s and the critical sliding velocity was between 1 and 6 m/s depending on the lubrican Although the greases have the same NLGI grade (2), they show quite different lubricating ability. The experiment showed that the lithium and lithium complex thickeners increased the lubrication ability of the base oil.