SAE J2789_201008

This procedure provides methods to determine the appropriate inertia values for all passenger cars and light trucks up to 4540 kg of GVWR. For the same vehicle application and axle (front or rear), different tests sections or brake applications may use different inertia values to reflect the duty-cycle and loading conditions indicated on the specific test. The validity of the results of a single-ended inertia-dynamometer test depends heavily on the inertia values. The objective of this Recommended Practice is to provide a common methodology for determining the inertia values for single-ended brake dynamometer testing. The test loads, energy levels, and rotational speeds during single-ended inertia-dynamometer testing are a function of the vehicle under evaluation. Since the majority of dynamometer tests use a single-ended configuration, a standardized methodology to determine the test inertia is necessary to ensure the consistency and usefulness of the test results. When using this Recommended Practice the value for the test inertia can be determined as a function of vehicle type, braking system configuration, vehicle parameters available, chassis dimensions, vehicle weights, center of gravity location, and deceleration level.