A chain should be replaced when its length becomes what percentage longer than its original length?

The correct percentage at which a chain should be replaced is 3%. Chains, especially in applications such as bicycles or machinery, are subject to wear and elongation over time due to factors such as tension, load, and environmental conditions.

Once a chain's length exceeds 3% of its original size, it is generally considered to have reached a point where it may no longer perform efficiently. An elongation beyond this threshold can lead to issues like skipped links, poor tension maintaining, or even failure during operation.

It's crucial for maintenance management to recognize this standard, as replacing the chain before it becomes excessively worn can prevent damage to other components and enhance the overall safety and reliability of the equipment.