How does the Park Tool CC-2 measure chain wear?

The Park Tool CC-2 Chain Wear Indicator takes the guesswork out of chain replacement by giving you a definitive go/no-go reading in seconds. The precision-machined gauge drops into chain links at a calibrated depth: if the tool seats fully, your chain has stretched past the wear threshold and needs to be replaced before it accelerates cassette and chainring wear.

Built from hardened steel for lasting accuracy, the CC-2 provides a simple, repeatable measurement that takes the subjective judgment out of chain service decisions. Catching a worn chain early is one of the most cost-effective things you can do for drivetrain longevity, and the CC-2 makes that check fast enough that there's no reason to skip it.