Bundle strength experiments were carried out on different types of cotton, using an HVI-system and an electromechanical tensile tester. The specimen preparations were varied systematically using a specially developed brushing station. By increasing brushing force and brushing time, increased tenacity values were recorded according to the different specimen types. It was established, through parallel investigations, that the measured increase in tenacity was due to intensifying the brushing process in the improved bundle geometry, which led to a homogenization of individual fibre stress in the bundles. As far as the minimalization of the type-specific differences is concerned, we recommend that brushing force in common HVI-systems be controlled exactly, selected as high as possible and brushing time lengthened if necessary. Consideration should be given to alternative clamping techniques.