Abstract:Diameter is the main parameter of the drums for forestry winches. Based on the established principles the matching relation between diameters of drums and cables has been studied. Accoding to the utilization grade and loading state of forestry winches, and to the structure and diameters of cables, a table of the matching relation between diameters of drums and cables has been given. The theoretical basis of design and the conditions of reasonadle application have been put forward for the drums of forestry winches.