Belt span is defined as the distance between the points on the sheaves where the belt touches each sheave.

• A. Distance between the centers of the shafts
• B. Distance around the belt path
• C. Distance along the belt between pulleys
• D. Distance between the points on the sheaves where the belt touches each sheave

Answer: (D)

In a belt drive, belt span is the straight distance between the two points where the belt makes contact with the pulleys—the tangency points. This is the length of the straight belt segment running directly from one pulley to the other, not the distance between the shaft centers, not the total belt path around the pulleys, and not the entire belt length. Knowing the span helps with tensioning and alignment because it defines the portion of belt that remains straight and under load between pulleys. To measure it, locate the tangency points on each pulley and measure the straight-line distance between them.