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Home > Bike Repair > Drivetrain

2 star rating

How to Check a Chain for Wear

by Levi Bloom

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


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.)


The tools for this repair can be purchased at:

Performance Bike, REI, or eBay.

Home > Bike Repair > Drivetrain