Ascertainment of driving lead of tractor front wheels as loaded by draft force

•Driving lead of tractor front wheels was ascertained as loaded by draft force.•The driving lead nonlinearly augmented when draft force augmented.•To manage driving lead, inflation pressure adjustment of tires is emphatically suggested.•Ballast weight application can be considered as another managing suggestion. Preceding researches proved that improper driving lead of tractor front wheels results in power circulation in transmission system, excessive wear of tires, premature rough ride, lower braking performance, and higher fuel consumption for mechanical front wheel drive (MFWD) tractor in rectilinear motion. For the first time, this study attempts to ascertain the driving lead dependency on draft force for the MFWD tractor which has not been yet addressed in the state of the art. To eliminate the effect of inflation pressure of high-lug radial tires on the driving lead, it was kept constant at 204 and 136 kPa for the front and rear wheels, respectively. The tractor was loaded by draft force required for fully mounted plow implement. It was found that the driving lead nonlinearly augmented from 1.86 to 8.08% as draft force augmented from 7.88 to 37.81 kN. Possible explanations and interpretations for this result have been completely documented in the paper. Overall, in order to manage the driving lead in admissible range in the loading operations, inflation pressure adjustment of the tires by means of commercial central tire inflation system is emphatically suggested as the first priority rather than ballast weight application.