Bike cassette and freewheel tools are used to remove and install the [cassette] or freewheel from the rear wheel of a bicycle.
A cassette is a cluster of gears that attaches to the rear hub of a bike and is controlled by the derailleur. A cassette typically has between 7 and 13 gears and is usually made up of individual cogs held together on a splined freehub body.
A freewheel is a type of rear gear cluster that attaches to the rear hub of a bike and is controlled by the rear wheel's backpedalling. A freewheel typically has between 5 and 8 gears, and it is usually made up of individual cogs that are held together on a threaded hub body.
Cassette & Freewheel Tools Explained
A cassette tool is a specific tool that is used to remove and install the cassette from the rear wheel. The tool typically has a square-shaped socket that fits onto the cassette lockring and a long handle that provides leverage for turning the tool.
A freewheel tool is a specific tool that is used to remove and install the freewheel from the rear wheel. The tool typically has a pin spanner or a screwdriver head that fits into the holes on the freewheel and a long handle that provides leverage for turning the tool.
These tools are essential for performing maintenance on the bike's drivetrain, such as replacing worn cogs, cleaning or lubricating the cassette or freewheel, or swapping out the cassette or freewheel with a different one. It's important to match the tool to the specific cassette or freewheel you're working with and to use the correct tool for the job, as using the wrong tool can damage the cassette or freewheel.
It's important to note that removing and installing a cassette or freewheel requires some mechanical skills and knowledge, it's not a task for a beginner, and it's recommended to have it done by a professional bike mechanic if you're not comfortable with the process.