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How to Check a Bike Chain for Wear

This guide will cover checking for chain stretch to see if your chain is worn out. No special tools are required.


  • 12″ ruler

1. With the chain still on your bicycle, line up the “0” end of the ruler with a chain pin.

2. Then look at where the “12” on the ruler hits the chain. There should be a pin that lines up exactly with the “12” (which is how it lines up on a brand new chain.)

3. If the pin-to-in spread isn’t exactly 12 inches, see how far off it is. The rule of thumb is to replace the chain if the pin is more than 1/8″ from the 12 inch mark. Less than 1/8″ off, it should be fine to keep riding it.

4. Measure again. I usually measure at three different spots on the chain, to be on the safe side.

5. Wait… Eventually the chain will need replaced, so keep checking on it. (If a worn chain is not replaced, it will accelerate wear on the rest of the drivetrain.)