RIGIC DISC   The use of a rigid disc in automotive and light truck applications is limited to vehicles with less than 50 horsepower and/or vehicles where the torsional damping capacity has been transferred to a dual-mass flywheel (DMF).

Single Stage Disc - This disc is used in the vast majority of pre-1990 automotive and light truck applications, both domestic and import. A single stage disc uses three to ten torsional springs around the hub flange, in order to control the heavier torsional loads generated by engines with more than 50 horsepower. This disc typically has six to ten degrees of torsional spring damper capacity. The single stage terminology is derived from the fact that the damper springs all work simultaneously with hub flange movement.

Idle Stage Damper Disc - Certain applications require a disc that includes an “idle stage damper”. Each damper is comprised of a series of friction washers located inside the disc, or a series of small secondary springs located between the hub and the torsional springs. The idle-stage damper is engineered to prevent damaging torsional spikes caused by engine vibration (primarily during start-up and shut-down) from destroying transmission gears. It also reduces drivetrain vibration and silences transmission gear noise at engine idle. An idle stage damper disc typically has up to three degrees of idle stage damper movement, along with the six to ten degrees of torsional spring damper capacity.

Series Damper Disc - Still other applications require a disc with an even greater ability to eliminate noise and damper torsional vibrations. In these instances, a “series damper” disc is used, which contains two rows of coil springs that compress in a sequential series. When the disc first engages, the outer row of springs compress, and then the inner row of springs compress as needed. A series damper disc can have up to 20 degrees of torsional spring damper capacity.