The excess signal loss in precision-wound optical fiber is measured as a function of the winding tension and the environmental temperature. Since the heat treatment of the wound fiber reduces the signal loss, the residual loss is attributed to the bending loss mechanism caused by the crossovers. A theoretical model is constructed to relate the distortion of the fiber to that of the buffer and is expressed in terms of the winding tension. Various mechanisms for the enhanced distortion at low temperature in current literature are examined along with the experimental data. The calculation is compared with the data with quantitative agreement.