This article presents the results of measuring yarn tension during winding 100 percent cotton carded yarn, Nm 34/1(29,4 tex), winding speed 10,00 m/s and 13,33 m/s, the force of yarn tension regulator 30 gl, the spinning cop 78g + or - 2g placed at 12cm from the yarn guide. With the support of the Excel 2007 software, yarn tension average and standard deviation of the yarn tension was determined. Hardness conical cross- wound bobbin is measured by the hardness HP5. The effect, of yarn tension to bobbin rigidity in many different positions and the average hardness was determined. Increase the hardness of the bobbin in the direction from small to large head of the bobbin and depends on the yarn tension on the winding. Research results achieved to create a scientific basis to set the yarn tension to achieve the bobbin stiffness depending on the requirements of the following technological processing stage on textile lines.