Technical considerations suggest that the two SAE rolling resistance test Recommended Practices, J1269 and J2452, need to be revisited, harmonized, and perhaps replaced with a single document. The examination and comparison of these two documents to support the work of the National Research Council committee on Tire Efficiency made some issues clear. Other issues became apparent in the process of modeling J2452, pseudo-coastdown, results given J1269, steady state, test data. In this paper the two J-Documents are explained, compared, and contrasted. The issues raised are discussed.