A combine harvester econometric simulation model was developed with the goal of matching the combine forward speed to the maximum harvested net income per acre. The model considers the machinery management costs of owning a combine and platform header for harvesting wheat. A statistical Design of Experiment (DOE) was used to evaluate the model using tri-level variables; the medium values constituted the model base case. Of the 27 input variables, the optimum speed was significantly influenced by the crop area, G/MOG ratio, grain unit price, field yield, field efficiency, grain moisture content, probability of a working day in the post-optimum period, estimated harvesting day length, and the timeliness importance factor. The developed optimum speed prediction equation estimated the full model well (R2 = 0.94). Five inputs significantly influenced both the optimum speed and the harvested net income: G/MOG, grain price, field yield, estimated harvesting day length, and the timeliness factor. It is expected that the developed econometric model will be useful for determining the real-time economic performance of a combine harvester.