Modeling the performance of an agricultural tractor with radial and diagonal tires on a firm soil

The tractive capacity and, consequently, the operational performance of the agricultural tractor depends on the characteristics of the tires. This study aimed to model the drawbar performance of an agricultural tractor equipped with radial and diagonal tires on a firm soil track with different force demands on the drawbar. An experiment was set up using a completely randomized statistical design in a split-plot scheme. The plots were made up of two types of tires (radial and diagonal), and the subplots were made up of six different forces, to which the tractor was subjected on the drawbar (1.4, 4.5, 10.5, 15.6, 19.9, and 23.3 kN), with three replications per treatment. A load cell was used to measure traction force, a flow meter for fuel consumption, and magnetic sensors for slippage. The results showed that the type of tire did not influence the hourly fuel consumption. Higher average values for specific fuel consumption, travel speed, and power available at the tractor drawbar were obtained with radial tires, while higher slippage values were obtained with diagonal tires. The modeling of the agricultural tractor performance allowed us to infer that the evaluated tractor behaved more efficiently, in terms of energy expenditure, on firm soil when equipped with radial tires than with diagonal tires.