Why is there no sound (also known as rattle noise) when I disengage the clutch with the EXEDY HYPER SINGLE?
This is because it has adopted the strap drive structure.
Rattle noise is generated in the boss drive type clutch.
With the boss drive structure, the pressure plate and the center plate becomes free when the clutch is disengaged.
The sound is generated when these plates rattle against the boss that is connected due to the fluctuation of the engine revolution. On the other hand, rattle noise is not generated with the strap drive structure because it is fixed with a strap plate (diaphragm spring) instead of the boss, so there is no rattling in the connection.
When the clutch is disengaged, a gap is created actively by the reaction force of the diaphragm spring, and it serves as enhancing the responsiveness of the disengagement.
This structure is currently adopted in many of the cars as genuine structure.