Cassette Removal Tools

What tools do you need to remove a cassette?

Cassette removal requires two tools working together:

Cassette lockring tool - Engages the splined interface on the cassette lockring, the threaded ring that holds the sprocket stack onto the freehub body. Most road and gravel cassettes use a Shimano-compatible spline pattern (also used by SRAM and most third-party cassettes). Campagnolo uses a different interface and requires a Campagnolo-specific tool. 

Chain whip - A length of chain attached to a handle, used to hold the cassette body stationary while you apply torque to the lockring tool. Without a chain whip, the cassette spins freely and the lockring won't loosen. These two tools are often sold individually or as a paired set, if you're buying for the first time, a matched set from Park Tool is the most reliable starting point.