Exedy Flywheels are made from solid one-piece billet chrome moly forged steel. They are specifcally designed to reduce weight and inertia for better engine response.
Most incorporate special design features to enhance the air flow to improve the cooling of the clutch. The ring gear teeth are milled onto the flywheel unlike an aluminum flywheel where the ring gear is pressed onto the flywheel and have the possibilities of seperating from the flywheel. This could cause the flywheel to explode due to two different expansion coefficients (aluminum flywheel pressed on steel ring gear).
Exedy steel billet and forged steel flywheels have passed engineering tests to 15,000 rpm. They are guaranteed to be explosion proof at the said rpm.