1. Scope

1.1 This SAE Recommended Practice establishes an inertia dynamometer test procedure, using exemplar caliper disc or drum brakes, to characterize the effectiveness of brake friction products for passenger cars and light trucks, up to and including 3500 kg GVW.

SAE J2430 provides a method of characterizing friction material effectiveness, using vehicle specific brake hardware and test conditions that approximate those for U.S. mandated new vehicle brake tests.

1.2 Rationale--SAE J2430 is an improvement over SAE J661/J866 as a friction material effectiveness characterization test of replacement brake linings. SAE J661 uses a one-inch square sample running against a large drum and is known to have shortcomings for characterizing the vehicle performance of different types of automotive brake linings.

1.2.1 SAE J2430 simulates certain sections of FMVSS 135. SAE J2430 is based on the controlled testing of unused friction materials against a new drum or rotor, using a prescribed set of test conditions that approximate those on a vehicle using the exemplar brakes. The FMVSS 135 vehicle test procedure emphasizes rapid braking from different speeds and includes a brake fade section.

1.2.2 Interactive conditioning between brakes occurs during vehicle braking. These interactions can affect work history for both front and rear brakes with a higher relative magnitude for rears. Variations in work history are known to cause variations in effectiveness. Also, it is recognized that brake effectiveness values can be influenced by brake and vehicle design, as well as by friction material characteristics.

For the previous reasons, material effectiveness comparisons using SAE J2430, should be based on testing with the same vehicle relevant brake and test conditions.

1.2.3 SAE J2430 is not intended to characterize all aspects of friction material effectiveness, such as light duty performance, environmental sensitivity, or effectiveness drift after extended service. Also, SAE J2430 is not intended to provide a reliable characterization of lining wear, noise, or drum/rotor compatibility in typical customer service vehicle usage.

1.2.4 SAE J2430 uses new, original equipment drums or rotors of prescribed chemistry, microstructure, and dimensions. Friction materials which require or use a unique mating surface may not be properly characterized by this test procedure.

1.3 Test Features--Brake effectiveness is reported as REGRESSED SPECIFIC TORQUE for ramp applications and as AVERAGE SPECIFIC TORQUE for torque and pressure controlled applications.

1.4 Test Application--Brake effectiveness values calculated from SAE J2430 may be used to aid in the selection of replacement friction materials for automotive disc and drum brakes that are similar in design and usage to that of the exemplar brake.

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