Optimum performance in an earth moving machine, such as a track-type tractor, is a function of many complex factors such as power delivered to the tracks, load, soil type, soil conditions, speed, terrain, etc. To determine an operating point associated with optimum performance, operational data may be collected, processed, and applied to known performance curves for well characterized conditions to develop recommended operating conditions. A coefficient of traction and a shear modulus adjustment, reflecting surface conditions, are calculated at the tractor during operation and used to offset a table of ideal condition operating points for use in soil characterizations. Using this and other inputs, a cycle power equation gives a curve that peaks at a theoretical optimum performance. However, the number of variables make an analytic solution impossible. An iterative approach determines a range of operating conditions associated with optimum performance.