This design for a lightweight flywheel was intended for use on my car. It was more a concept than anything as I had little experience machining parts at the time. Basic shear and bearing stress equations were used, along with a safety factor of 2.0, to ensure that this flywheel would indeed be usable if ever created. It was to weigh approximately 10lbs, a nice reduction from the 29lb unit found on the engine from the factory. In hindsight, a flywheel that light would have allowed for unbearable vibrations on a four cylinder daily-driver.