Which of these components is NOT part of a dual mass flywheel?

A dual mass flywheel is designed to absorb vibrations and manage power delivery in a manual transmission system. It consists of two flywheel masses (primary and secondary) connected by springs, which assist in dampening engine vibrations and improving the smoothness of power transfer.

The primary and secondary flywheel are integral components, as they allow for independent motion to help reduce the impact of engine vibrations on the drivetrain. Springs are also essential within this system, as they provide the necessary compliance between these flywheels.

A grease fitting, while commonly used in various mechanical components for lubrication purposes, is not typically part of a dual mass flywheel's structure. Instead, the design relies on the materials and engineering of the flywheel components themselves to minimize wear and maintain effective operation without the need for re-lubrication through a fitting.

This makes ball bearings the correct choice because they are not a standard component found in a dual mass flywheel setup, which instead focuses on the combined functionality of the masses and springs for damping and power transmission.