Dual-mass flywheel (DMF)

A two-part flywheel with springs between the halves, used on many manual cars to damp engine pulses.

Also called: DMF · two-mass flywheel

What it means

Definition

Schaeffler, which manufactures them, describes the dual-mass flywheel as an integrated spring/damping system that promotes extra-smooth running and reduces engine noise. Installed between the engine and the transmission, it prevents torsional vibrations from the piston action of the engine from propagating along the drive train to the transmission. A conventional flywheel is a single solid disc with no such damping.

Why a buyer cares

What it changes

It sits behind the clutch, so clutch work on a car with one reaches the flywheel too, rather than being a matter of resurfacing a solid disc.

In practice

Where you meet it

Not visible without removing the transmission — it appears in parts diagrams and clutch-job invoices.

Two things that look alike

Not the same as

A solid flywheel is one rigid disc; a DMF is two masses that can move against each other through springs.

Where this comes from

Sources

Schaeffler's material explains how a DMF works, not how it wears out — the same gap the site's existing clutch-and-flywheel file has. Its diagnosis brochure returns 403 to automated fetching.