Cord Load Characteristics in Bias and Belted-Bias Tires

Two improved versions of a recently developed miniature force transducer were used to measure cord loads at the crown, shoulder, and sidewall of bias and belted-bias automobile tires under different testing conditions. As a transducer at a given location passes through the footprint, a “basic shape” for the cord force pattern is generated for straight ahead rolling and cornering. Factors such as wheel load, inflation pressure, obstacle impact, tire speed, rim width, and frictional properties of the tire-drum interface can affect the total force excursion and/or the base line value but do not affect the basic shape of the patterns. For both bias and belted-bias constructions significant ply-to-ply cord force variations were detected, and the cord force pattern observed in the first ply as the transducer passes through the footprint is nearly a mirror image of that in the second ply at the same location.