This study presents a comprehensive analysis of the coupled influence of acceleration and speed on displacement errors in ball screw feed systems. A micromechanical model based on ball elastic deformation is developed to investigate the respective contributions of centrifugal forces (from speed) and inertial forces (from acceleration) to displacement errors. Numerical simulations reveal that the displacement error increases approximately linearly with acceleration. Furthermore, the concept of an error jump value is introduced to illustrate the significant influence of preload on system stability during startup. Sensitivity analysis confirms that appropriately increasing the preload can reduce the error jump value, thereby improving dynamic stability. Based on these findings, a novel preload optimization strategy is proposed to achieve a balance between precision and stability. Compared with conventional empirical methods, the proposed strategy significantly reduces additional friction losses while maintaining high precision and operational stability.