Biological Systems Engineering


Date of this Version



Published in Applied Engineering in Agriculture Vol. 27:5 (2011), pp. 711‐715. Copyright (c) 2011 American Society of Agricultural and Biological Engineers. Used by permission.


Nebraska law requires the Nebraska Tractor Test Board of Engineers to compare results of the tests of an agricultural tractor model with the manufacturer's claims regarding power, fuel use, and other performance ratings in order to recommend a permit to sell that tractor model in the state. PTO tests are conducted to verify the manufacturer's PTO power and fuel claims for tractor models. In recent years, several tractor manufacturers have been producing models of large tractors either without a PTO or with a PTO not capable of transmitting the full engine power and, therefore, have chosen to advertise engine power. The objective of this project was to determine a reasonable alternative to removing engines from these tractors for tests to determine whether these tractors met their power claims. Linear regression analyses of advertised engine power claims and OECD Code 2 drawbar power test results from 48 tracked (R2 = 0.98) and 43 4WD tractors (R2 = 0.99) were used to establish two linear relationships to verify the engine power claims for these tractors. These relationships provide a reasonable means of verifying engine power claims for large agricultural tractors without a PTO, or without a PTO capable of transmitting full engine power.