To verify the justification for an amendment of European StandardEN 14770:2023, this study investigates the effect of trimming on measured shear modulus and phase angle of bituminous binders using Dynamic Shear Rheometer (DSR). Six bituminous binders were analysed, including penetration grade neat bitumen and modified bitumen with polymer and wax. More than 400 DSR measurements (with trimming versus without trimming) were conducted at 10 rad/s at different temperatures. The comparisons between test results indicate that the effect of trimming on DSR measurements depends on the plate size used for the measurement. With the plate-plate geometry PP25 (diameter 25 mm and thickness 1 mm), whether trimming the specimen or not does not affect the DSR measurement repeatability or make a difference larger than the repeatability of the standard test method. However, with the plate-plategeometry PP08 (diameter 8 mm and thickness 2 mm), the trimming process has a more significant effect, particularly on shear modulus |G*|. But the effect of trimming as a single factor does not exceed the reproducibility limits of the standard test method.