Chain ______ is measured by rotating the sprockets so that there is little to no chain sag in the taut side and measuring the sag in the slack side.

• A. Tension
• B. Sag
• C. Elongation
• D. Slackness

Answer: (B)

Chain sag is the amount the chain drops when the drive is properly tensioned. To measure it, you rotate the sprockets so the taut side has almost no sag, then measure how far the chain sags on the slack side. This sag value indicates how loose the chain is and whether the tension needs adjustment. Tension refers to the force carried in the chain rather than how much it sags, elongation is permanent stretch from overuse, and slackness isn’t the standard term used for this specific measurement.