performance spreadsheet for radial tires.

Abstract

Lotus-compatible templates were revised from the Zoz (1987) spreadsheets. Performance of two-wheel-drive (2WD) and four-wheel-drive/mechanical-front¬wheel-drive (4WD/MFWD ) tractors were predicted on agricultural soils for radial tractor tires. Comparisons between the predicted and experimental results of 41 tractors using radial tractor tires showed fair agreement. The performance parameters used in the comparisons were wheel slip, drawbar pull and tractive efficiency. The percentage differences were calculated and the acceptable range was set at 20% difference. For wheel slip, 22 out of 41 tractors had percentage differences that fell within the acceptable range. The drawbar pull comparison showed that 35 out of the 41 tractors had percent differences within the acceptable range. The tractive efficiency comparison showed that 27 out of 33 tractors had percentage differences that fell within the 20% range. The predicted drawbar pull and tractive efficiency were higher than the experimental values in most cases of MFWD tractors. Because some input values for the spreadsheet such as available power, cone index and travel speed were not given in the source of data, the predicted results of tractor performance were not in close agreement to experimental results.