Over the past several years much discussion has occurred about the differences of fiber bundle tenacity measurement between the two types of HVI systems. Since the methods employed to measure linear density are different, it has been suggested that an absolute standard, such as the Stelometer or an Instron should be used. The present study examines how the shape of fiber bundles in strength tests affects strength. Some preliminary experimental data have been collected on long, medium and short cotton fibers to support the authors' conclusions.