SAE J2315_199802

The purpose of this test is to evaluate the axial strength of the nut seat of wheels intended for use on passenger cars, light trucks, and multipurpose vehicles. In addition, a minimum contact area is recommended to ensure enough strength for the rotational force in tightening a nut against the nut seat. While this test ensures the minimum strength of the nut seat, the wheel must also have a degree of flexibility. This flexibility, as well as bolt tension, are important to maintain wheel retention. The nut seat task group of the SAE Wheel Committee developed this procedure. The test values and procedure were developed by testing actual wheels by various manufacturers and of various materials to ensure that the procedure provided a method to evaluate the nut seat axial strength. The tests used for the standard’s development were the torque tension tests and field experience with higher cornering applications that could cause nut seat collapse or cracking. The procedure is for the evaluation of the nut seat for wheels made of aluminum or steel. The yield characteristics that are described in 3.4 do apply differently to cast wheels since the test is intended to deform the fabricated nut seat. A cast structure may crack instead of deform and this is covered in the performance requirements. The Deformation test (3.3) will measure nut seat deformation and emboss collapse or cracking (elastic and plastic deformation). This test procedure evaluates the axial strength of the nut seat. The loading due to turning of the nut against the nut seat is not accounted for except in the referenced tables on nut seat bearing area. The stress differential method of evaluation accounted for this loading to obtain the listed values. The nut seat should have the axial strength as defined in this procedure. The nut seat should have sufficient flexibility to maintain torque in service and meet fatigue requirements. The fatigue tests in SAE J328 can be used for this evaluation. The clamp force evaluation is defined under the systems test in SAE J2316.