A twin-disc tribometer assembly includes a first sample drive shaft arranged to receive a first sample disc and a second sample drive shaft arranged to receive a second sample disc; a first drive motor configured to rotate the first drive shaft and a second motor arranged to rotate the second drive shaft. The first and second drive shafts are configured to be positioned relative to each other such that a sample disc mounted on the first drive shaft will make a point contact with a sample disc on the second drive shaft as the drive shafts rotate. The assembly is configured to allow the shafts to rotate relative to each other in a non-continuous reciprocating motion or a non-collinear motion where one sample disc is tilted with respect to the other.