A pneumatic tire having: a tire cavity defined by an inner liner; an air inlet housing affixed to the inner liner; and a first sidewall having an elongate sidewall groove therein containing an elongate air tube having an elongate internal air passageway; wherein the air tube is located to operatively compress segment by segment from an expanded diameter to a substantially reduced diameter responsive to a bending strain introduced into the first sidewall from a rolling tire footprint whereby forcing air segment by segment along the air tube internal air passageway; wherein the air tube has a substantially on-side mushroom-shaped sectional profile extending radially into the first tire sidewall, the air tube having a radially inward cap of relatively larger diametric dimension affixed to a radially outward tube stem of relatively smaller diametric dimension, the inward tube cap residing within an a relatively larger diametric region of the sidewall groove and extending in a lateral outward direction from the tube stem in an orientation substantially parallel with an outward surface of the first sidewall; wherein the tube stem has a tapering sectional profile defined by converging sides extending in a radial direction outward from the tube cap to a radially outward stem end surface; wherein the tire comprises and elongate tubular inlet conduit extending between the air tube and the inlet housing, the inlet conduit having an internal air passageway operative to route inlet air from within the inlet housing to the air tube internal air passageway; and wherein the inlet conduit connects in air flow communication with first and second opposite ends of the tube internal air passageway and is also used to route compressed air from the air tube into the tire cavity. a tire cavity defined by an inner liner; an air inlet housing affixed to the inner liner; and a first sidewall having an elongate sidewall groove therein containing an elongate air tube having an elongate internal air passageway; wherein the air tube is located to operatively compress segment by segment from an expanded diameter to a substantially reduced diameter responsive to a bending strain introduced into the first sidewall from a rolling tire footprint whereby forcing air segment by segment along the air tube internal air passageway; wherein the air tube has a substantially on-side mushroom-shaped sectional profile extending radially into the first tire sidewall, the air tube having a radially inward cap of relatively larger diametric dimension affixed to a radially outward tube stem of relatively smaller diametric dimension, the inward tube cap residing within an a relatively larger diametric region of the sidewall groove and extending in a lateral outward direction from the tube stem in an orientation substantially parallel with an outward surface of the first sidewall; wherein the tube stem has a tapering sectional profile defined by converging sides extending in a radial direction outward from the tube cap to a radially outward stem end surface; wherein the tire comprises and elongate tubular inlet conduit extending between the air tube and the inlet housing, the inlet conduit having an internal air passageway operative to route inlet air from within the inlet housing to the air tube internal air passageway; and wherein the inlet conduit connects in air flow communication with first and second opposite ends of the tube internal air passageway and is also used to route compressed air from the air tube into the tire cavity.