marcel or “cushion” segments. The segments are made from heat-treated, stamped, spring steel and a wave is formed in them during the stamping process. The wave softens engagement and minimizes chatter when the pressure plate forces the disc in contact with the flywheel. Each segment is riveted to the retainer plate, which is exposed on the flywheel side of the disc. The hub flange is located in the center of the disc between the retainer plate and a cover plate that is exposed on the pressure plate side of the disc. Torsional springs nestled around the hub flange absorb shock during engagement. The splines on the hub match the splines on the input shaft.

AMS Content

As we’ve shown, each disc assembly is engineered to fit within a series of size and weight parameters that are based on desired levels of fuel consumption, driver comfort, torque capacity, and vibration suppression. In order to address the specific requirements of each application, AMS relies exclusively on disc assemblies produced by select O.E. manufacturers.

While off-shore “knockoff” discs may appear identical, rotary fatigue tests prove otherwise. By relying primarily on dimensional specifications, suppliers of aftermarket knockoffs fail to ensure that the replacement disc will meet the necessary functional criterion. In almost all instances, these look-alike discs fail to meet even the minimum O.E. standards set at 1,000,000 engagements. Hub flanges, torsional springs, retainer plates, and cover plates have all failed at less than 28% of the minimum criterion during testing.

As is the case with pressure plate assemblies, vehicle manufacturers may rely on more than one O.E. producer to provide disc assemblies for the same make and model year vehicle. Additionally, other O.E. producers will tool up an aftermarket design, leading to non-compatibility issues with mating components.

Sorting through these issues requires extensive testing and impartiality. Each AMS disc is tested for dimensional and functional characteristics including lateral run-out, marcel deflection, torsion durability, spring rate, and material density. This information is then cross-referenced using IDD compatibility analysis (see IDD section for more details). What’s more, our status as an independent supplier guarantees that we aren’t tied to defective designs and/or obsolete tooling. Whereas other suppliers may continue to supply substandard and defective components, simply to recoup fixed PP&E costs and tooling costs, we simply chose the best designs from the best suppliers.

Finally, our cataloging reflects the high standards set forth by vehicle manufacturers. Each application listing is based on the functional requirements used in the vehicle when it was new. Dimensionally similar substitutes simply aren’t allowed as replacements in applications that require innovative designs and materials to address performance characteristics. For example, General Motors uses the same pressure plate assembly in certain gas and diesel truck applications because the clamp load requirements, torque capacity, and release characteristics need not change. However, the diesel application requires a disc design that will damper torsional spikes, reduce drivetrain vibration, and silence transmission gear rattle. While the dimensional characteristics of the gas disc are identical to the dimensional characteristics of the diesel disc (both are compatible with the same pressure plate assembly), use of a gas disc in the diesel application will eventually result in premature clutch system failure or damage to the transmission.

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