Schwungräder

The flywheel is a heavy disc bolted to the engine crankshaft. It stores rotational energy to keep the engine turning smoothly between power strokes, helps balance the engine, and provides the friction surface the clutch clamps against. Its outer edge carries the starter ring gear used to crank the engine.

As the engine fires, the flywheel absorbs and stores rotational energy, then releases it to keep rotation steady during gear changes and at idle. The clutch disc clamps against the flywheel face to transfer power to the gearbox, and at start-up the starter motor turns the ring gear on the flywheel edge to crank the engine. A dual-mass flywheel adds a damping layer for smoother shifting.

The friction face can wear, score, or develop heat spots from a slipping clutch, and the starter ring gear teeth can wear or break. Signs include vibration, a juddering clutch, or starting trouble and grinding from the starter. The flywheel is inspected whenever the clutch is replaced, and a face that is scored or below limits is resurfaced or replaced. Mounting bolts are tightened to the manufacturer specification to preserve balance.

The correct flywheel depends on the engine and gearbox, the clutch it works with, and whether the design is solid or dual-mass. Confirm the part against the vehicle specification before fitting.