Velocity ratio: The velocity ratio of a belt drive is defined as the ratio of the speed of the driven pulley to the speed of the driving pulley. Effect of slip on transmission: Result of belt slipping is to reduce the velocity ratio of the system and decrease in efficiency of transmission. Effect of creep on transmission: When the belt passes from slack side to tight side, a certain portion of the belt extends and it contracts again when the belt passes from tight sight to slack side. Due to these changes in length, there is a relative motion between the belt and the pulley surfaces. This relative motion is called as creep. The total effect of creep is to reduce slightly the speed of the driven pulley or follower.
