Dual Mass Flywheel

A dual-mass flywheel is essentially two flywheels in one that provides spring cushioning to dampen torsional crankshaft vibrations and shock loading when the clutch is engaged. The two-piece assembly has a front "primary" mass and a rear "secondary" mass. The primary mass bolts to the crankshaft like an ordinary solid flywheel, and includes the ring gear for the starter. The clutch is bolted to the secondary mass, which is separate from the primary mass, but attached to it with a series of coil springs mounted sideways between the two. The springs allow just enough movement between the masses to transmit less engine vibration to the driveline, reduce some of the jarring and stress on the transmission and the remainder of the drivetrain when the clutch is engaged. The cushioning effect also reduces shock loading on the transmission for longer gear life and less noise.