( 
Prior to the start of the experiments, preliminary free rolling is done to the 
test tire with a vertical loading of 425 kg on the drum. The inflation pressure 
of the tire is always kept at the designated values of 1. 7 and 2.0kg/cm by 
loading vertically with 425 kg during the experiment. 
(2) Experimental Items for Measurement 
l. Deformation of Tire during Free Rolling 
Continuous photographing of the tire during free rolling is taken from zero 
speed to higher speeds. 
Several pairs of tire photographs taken at speeds of 0 km/h, 80 km/h. 
120 km/h and 160 km/h, are used for the measurement of deformation. 
Results of the measurement are represented as follows. 
a. Contour mapping of deformation of the tire during free rolling 
b. Sectional change toward the radial direction at the perpendicular to the 
drum from the center of tire and at the section having the angle of 22° and 19. 5° 
against the plum line from center of tire. (Three sections are shown in each 
figure of contour mapping). The three sectional changes are drawn. 
2. Deformation of Tire During Braking 
During the free rolling of the tire at a speed of 60 km /h, braking torque 
has increased and the tire finally stops running on the drum. (Circumferential 
Speed is kept at a constant speed of 60 km/h ). Photos are constantly taken 
at each one second intervals with a synchronized strong intensity flash unit 
from the start of applying the braking torque to the time the tire stops. At 
the same time, the oscillograph recorder is used to determine the braking 
torque during photographing. The relationship between braking torque and 
deformation of the tire in tangential direction is analysed. 
Several sectional deformations in the case of applied torque values of 4, 0, 
42.5 and 73 kg-m, are measured and three deformation contour lines were 
drawn. Deformation change at six sections in braking were drawn. The six 
sections are shown in figures of the deformation contour line. They are sections 
of plumb line, having of 15°, 30° and 45° against plumb line, 
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