Abstract: A clutch disc spring for a land vehicle, such as an over-the-road truck or an automobile, which has an increased life. The spring, formed of ferrous material, is cooled by vaporizing low temperature nitrogen to slowly, cryogenically cool the spring to a temperature of about −300 degrees Fahrenheit and maintain the spring at that temperature for several hours. The cryogenic treatment converts retained austenite within the spring to martensite, thereby improving the mechanical properties of the spring. The spring is then tempered to temper the newly formed martensite, further improving the mechanical properties of the spring. These improved mechanical properties include better wear resistance, strength and resistance to fatigue.