METHODS are outlined for measuring the characteristics of tires that affect riding-qualities, and typical curves showing rate of deflection and contact area versus tire size are presented. Coordination of service performance with simple laboratory tests is illustrated. Means of securing the inter-effect of tires and springs are outlined and curves of typical axle-body frequency versus tire size are shown. Use of the solenoid accelerometer in conjunction with equipment for interpretation of physical effect of accelerations is suggested for service tests. Secondary riding-quality factors such as tire traction, horsepower and rim diameter are discussed and numerous others mentioned. The influence of tread design and other factors of tire design is indicated.
Discussers raise questions regarding change in inflation pressure with a change to a rim of smaller diameter and a tire of larger section; absence in the low-pressure cord tire of the damping effect of friction in the carcass of the high-pressure woven-fabric tire; effect on tire deflection due to use of wider rims; portion of the load supported by stiffness of the tire walls; distribution of pressure over area of tread contact, increased pressure at the edges of the tread giving better traction; increase of coefficient of friction by non-skid tread; reduction of noise by use of rib-type tread; and effect of present tendency to use thicker tubes and heavier super-tires.
Additional research on how to rate the load capacity of tires of different diameter is said to be needed.
Instrumental research is asserted already to have shown that certain upholstery materials have marked value in reducing noise in the body.
Avoidance of synchronism of periods of the front and rear-end unsprung weight with each other and with the car body is commented upon as important to riding comfort.