How to select air pressures in the tires of MFWD (mechanical front-wheel drive) tractor to minimize fuel consumption for the case of reasonable wheel slip

• Fuel savings when MFWD tractor slip is normalized.
• Relation between the tire pressures, kinematic mismatch and fuel consumption.
• Tire pressures that ensure a minimum kinematic mismatch between front/rear wheels.
• Tire pressures combinations were validated in accuracy by theoretical and experimental results.

In agriculture, tractor is the most fuel-consuming machine. The research indicates that 20–55% of available tractor power is lost in the process of interaction between tires and soil surface. Tire pressure and vertical wheel load are both easily managed parameters, which play a significant role in controlling the slip, the traction force and the fuel consumption of a tractor. The purpose of the research was to base theoretically and experimentally the tire pressures that ensure a minimum kinematic mismatch between the drive wheels for MFWD (mechanical front-wheel drive) tractor, and thereby reduce the fuel consumption at a reasonable tire slip. Close to one coefficient of kinematic mismatch between the front and the rear wheels was observed when combinations of pressures in the rear/front tires were made, respectively: 150/70, 190/110, and 230/115 kPa. When tractor (MFWD) was driving on a hard road surface without thrust load and with above mentioned tire pressure combinations, the lowest fuel consumption was reached, namely, in the range from 3.75 to 3.8 L h−1.