Replaceable tread tires

Claim 1

A pneumatic tire assembly including: a generally toroidal carcass portion having axially spaced beads, radially outwardly extending sidewalls, a crown section and carcass shoulders intermediate the sidewalls and crown section, said carcass shoulders being built-up and enlarged with respect to said crown section, said carcass having high angle bias ply cords of about 75° with respect to the intended direction of tire rotation and extending from bead to bead and defining an ovate cross-sectional configuration with a relatively flat, continuous, upper surface extending entirely across the crown and carcass shoulders to define a tread receiving area, and a generally cylindrical replaceable tread portion removably mounted upon the upper surface of said carcass portion, said tread portion having a central area and tread shoulders extending from the edges of the tread portion, said tread shoulders being built-up and enlarged with respect to the rest of the tread portion, said tread portion also including a plurality of layers of ply cords extending entirely across said tread portion at 0° from the intended direction of tire rotation, the tread portion defining an axially elongated cross-sectional configuration with a relatively flat, continuous radially inner surface across its entire width to constitute an area for mounting upon the tread receiving area of said carcass portion with the carcass shoulders in overlying contact with said tread shoulders and with the interface of said carcass portion and said tread portion defining in cross-section a radius of curvature of from about 500% to infinity of the inflated carcass section width at its widest dimension whereby said replaceable tread portion is maintained on said carcass portion during use by inflation pressure within said carcass portion.