5 Reasons Your Chainsaw Chain Keeps Derailing

Loose chain tension Loose tension is the most common cause of derailing. Chains stretch with use, so tension before each session until the chain just touches the bottom of the bar rail with about a 1/16-inch gap.

Worn or damaged bar rails Burred, uneven, or cupped rails let the chain wander. File down raised edges, and replace the bar if the rails are too wide or cupped.

Worn sprocket tip A worn sprocket tip or bad bearings will throw the chain. Inspect and replace if necessary.

Wrong chain pitch or gauge Using the wrong chain pitch or gauge for your bar guarantees derailing. Always match sizes.

Over-tightening the chain Running the chain too tight kills the bar and chain. Stick to the recommended gap.