A drop-in style gauge that measures bicycle chain wear.

Keep chain wear in check

The Park Tool CC-4.2 Chain Checker accurately measures a long section of chain and comes in contact with the chain in three places, taking the guesswork out of judging chain wear.

The tool works on any 5 to 13-speed chain or single-speed chain and is designed to indicate when a chain reaches 0.5%, 0.75%, and 1.0% wear.

Product details

1. Replacement guidelines – Two-sprocket (single-speed) chains: replace chain at or just before 1.0%
2. Replacement guidelines – 5-to-10-speed chains: replace chain at or just before 0.75%
3. Replacement guidelines – 11-to-13-speed chains: replace at or just before 0.5%