A high deflection and laterally stable pneumatic tire (10, 28), comprising a trapezoidal structure defined in an unloaded cross section passing through an axis of the tire and delimiting a tire interior, wherein said structure is configured with a) a tread (2, 30, 62) having a substantially linear ground engageable surface; b) a widest tire region at or near said tread portion; c) two opposed substantially straight sidewalls (7, 8); and d) a bead (13, 37) at a corresponding terminal end of each of said sidewalls which is engageable with a rim of the tire, wherein axial bead spacing between two of said beads and defining a width of said rim is less than a width of said tread portion, so as to generate a footprint which engages an underlying ground surface by a substantially uniform pressure during high deflection conditions, wherein the tread (2, 30, 62) has two opposed substantially straight, lateral terminal walls such that the substantially linear ground engageable surface extends between said two lateral walls and the widest tire region is at or near said two lateral walls of the tread, each of said two lateral terminal walls having a radially outward portion coinciding with the ground engageable surface and a radially inward portion, wherein the sidewalls (7, 8) extend obliquely from the radially inward portion of a corresponding one of said two substantially straight, lateral walls of the tread to said corresponding bead (13, 37), wherein the two substantially straight sidewalls are uncompressed, when the tire is mounted on the rim and unloaded, and wherein the trapezoidal structure dimensionally satisfies the following two relations for an unloaded tire: a partial height of the tire from a periphery of the rim to the widest tire region is greater than, or equal to, 0.55 times a maximum tire height from the rim periphery to a ground engaging edge of the tread (2, 30, 62); and a width of the tire from the rim periphery to the widest tire region is greater than, or equal to, 0.4 times said partial height, wherein, when the tire is mounted on the rim, one of said oblique and substantially straight sidewalls which is subjected to a lateral movement resisting force being transmitted from said tread to said rim upon application of a lateral force onto the tire (10, 28) is able to resist a lateral movement causing force applied by compressed air within said tire interior and to resist relative movement between said rim and said tread. a) a tread (2, 30, 62) having a substantially linear ground engageable surface; b) a widest tire region at or near said tread portion; c) two opposed substantially straight sidewalls (7, 8); and d) a bead (13, 37) at a corresponding terminal end of each of said sidewalls which is engageable with a rim of the tire, wherein axial bead spacing between two of said beads and defining a width of said rim is less than a width of said tread portion, so as to generate a footprint which engages an underlying ground surface by a substantially uniform pressure during high deflection conditions, a partial height of the tire from a periphery of the rim to the widest tire region is greater than, or equal to, 0.55 times a maximum tire height from the rim periphery to a ground engaging edge of the tread (2, 30, 62); and a width of the tire from the rim periphery to the widest tire region is greater than, or equal to, 0.4 times said partial height, wherein, when the tire is mounted on the rim, one of said oblique and substantially straight sidewalls which is subjected to a lateral movement resisting force being transmitted from said tread to said rim upon application of a lateral force onto the tire (10, 28) is able to resist a lateral movement causing force applied by compressed air within said tire interior and to resist relative movement between said rim and said tread.