The Park Tool CTP-4K Replacement Chain Tool Pin Kit is a precision service part designed to refresh your Park Tool chain tool and keep it functioning smoothly. Over time, the driving pin in a chain breaker can wear, bend, or dull from repeated use — which can make pushing pins in and out of bike chains more difficult or risk damaging the chain. This replacement pin kit gives your chain tool renewed life by providing a fresh, accurately machined pin that restores dependable performance.

Made to Park Tool’s exacting specifications, the replacement pins are engineered to fit select Park chain tools that use a removable driving pin. Installing a new pin ensures the tool maintains correct alignment and force when driving chain pins — helping you install, remove, or size chains with confidence. Whether you’re a home mechanic, workshop pro, or simply doing routine drivetrain maintenance, keeping spare replacement pins on hand prevents delays and keeps your chain tool ready when you need it most.