How many drive links are specified for a 20-inch chain in the Common Chain configuration?

• A. 60 drive links
• B. 72 drive links
• C. 84 drive links
• D. 90 drive links

Answer: (B)

Drive links are the fixed-length units that make up the loop of a chainsaw chain, and the number you need is set by the bar length and the common configuration used. In the Common Chain setup, the bar length determines how many drive-link units fit around the loop so the chain sits properly in the bar groove and can be tensioned correctly. A 20-inch bar is paired with 72 drive links, which ensures the chain wraps fully and engages the drive sprocket at the right tension.

Think of it this way: each drive link is a standard segment of the chain, and the bar length dictates how many of those segments are required to make a complete loop around the bar. Longer bars need more drive links, shorter bars need fewer, and the numbers you see (like 72 for 20 inches) come from the standard chart used to keep things consistent. Shorter bars (for example) would use fewer drive links, while longer bars would use more, keeping the chain properly matched to the bar and powerhead.