Lower Pressure Tires on a Sand Dune Field

Abstract

In order to find out whether lower pressure tires would be able to be utilized on a sand dune field, the authors tried to investigate the different effects on the performances between a conventional tire and lower pressure tires if the weight on the wheels and the inflation pressure were changed. Tractor used in this experiment was a walking tractor, which was powered by 4.5ps/1500rpm engine. The following results were obtained.
1) By changing inflation pressure under the condition of the same weight on the driving wheels, the driving force and the drawbar pull become larger with the decrease of inflation pressures.
2) By changing the weight on the driving wheels under the same inflation pressure, the driving force and the drawbar pull increase with the additional weights on the driving wheels, but increasing of the driving force is larger than that of drawbar pull.
3) Comparing the driving characteristics of different tires with the same slipping ratio, rolling resistance decreases while the drawbar pull increases, when the width of the tires of the same diameters increase. Increasing both the diameter and the width of the tires, driving forces increase. However, rolling resistance is not always decreased.
4) Rolling resistance has a tendency to increase depending on the decrease of inflation pressure under the condition of the same weight on the driving wheels. At lower inflation pressure such as 0.4 or 0.6kg/cm², the coefficient of rolling resitance is observed to have a decreasing tendency depending on the increasing weight on the driving wheels, while in the higher inflation pressure i. e. 0.8, 1.0 or 1.2kg/cm², this remains nearly constant.
5) Driving forces at 100% slippage increase proportionate to the additional weights on the driving wheels but these are different between tires or inflation pressures.
6) Lower pressure tires show better tractive performance than a conventional tire on a sand dune field, and would be able to operate to some extents.