In preceding report of this series, it was recognized that the value of side-force calculated with he theoretical equation, obtained by developing the theory of E. Fiala, agreed well with the experimental results on rolling wheel.
In this paper, the applicability of this theoretical equation was discussed based on the results obtained by the experiment on driving wheel, using both smooth and agricultural tire
Main results were as follows:
1. The hydothesis that the value of side force calculated with the equation was equal to the experimental value, was acceptable at a level of 0.01 by the chisquare criterion. The mean percentage error of experimental values was within 5 percent at each side slip angle. From these results, it was clearly recognized that the side force of driving wheel was calculated rightly with the equation.
2. The value of C that was a factor of cornering coefficient, obtained by the method of least squars, became very small with the increase of tractive force for smooth tire, but there was no very much change for agricultural tire. From these results, agricultural tire was more useful than smooth tire, though the running stability for side slipping was worse in comparison with smooth tire at small traction force.
3. The coefficient of lateral dynamic friction became slightly small with the increase of traction force for smooth tire, but conversely large for agricultural tire owing to the increase of lug deflection.
4. The dynamic frictional resistance of both smooth and agricultural tire was indicated by the half of the diamenter of elliptical shape.