a three lower samples 8 mounted symmetrically to each other in the form of leaves are in tribological contact with the ball 7 the leaves 8 are supported by a holder 9 which is supported subsequently by a spring 10 the holder 9 and the spring 10 define the spring unit designated as 3 which extends over a length of arrow 3 u2032 the spring constant of the spring unit 3 can advantageously if need be automatically be changed via the control and evaluation unit 40 by an adjustment mechanism or adjustment unit 13 the spring unit 3 is located on a carrier 11 which is insertable and if necessary drivable into a bearing 12 of the rheometer 1 which is near the base in the present case the sample 7 is rotated with the measurement shaft 6 the spring properties of the spring unit 3 are representative of the spring properties of the entire rheometer 1 or of an oscillatory circuit 30 which as indicated by the arrow comprise all of the movable particularly spring elastic movable parts of the rheometer 1 in the path or circle of force or power circuit which are deformable when force is applied to the samples 7 8 and thus have the possibility of appearing spring effectively or of exerting forces on the samples 7 8 which can generate resonances or oscillations in the oscillatory circuit 30 together with the carrier 11 the spring unit 3 constitutes a module or a tribological measurement module cell insertable into a rheometer 1 according to the present invention the spring unit 3 with the carrier 11 can be exchangeably.