Asseiro, A. and Kaye, S., "Spring Steel Grade Development for Automotive Suspensions," SAE Technical Paper 930968, 1993, doi:10.4271/930968.
Current suspension system designs require coil springs that are both lightweight and compact. A new microalloyed coil spring grade, SAE 9259 Modified, has been developed that can successfully withstand the higher stresses experienced by these springs. Spring performance at elevated stress and hardness levels was measured and compared to those available from four commercial spring grades used in North America and Japan. At 10 percent higher operating stress (1080 MPa), SAE 9259, SAE 9259 Modified, SAE 9254, and SAE 9254 Modified springs have sag and fatigue properties that are equivalent to, or better than, conventional SAE 5160 springs, yet are 15 percent lighter.