An article of footwear having an upper and a sole structure secured to the upper , the sole structure comprising: a fluid-filled chamber that encloses a pressurized fluid, the fluid-filled chamber having a first surface, a second surface, and a sidewall surface, the first surface being oriented to face toward the upper , the second surface being located opposite the first surface and oriented to face away from the upper , and the sidewall surface extending (i) between the first surface and the second surface and (ii) around at least a portion of the fluid-filled chamber ; and wherein the fluid-filled chamber comprises a reinforcement member being formed from a material having a greater modulus of elasticity than a material forming the fluid-filled chamber , the reinforcement member including a chamfered surface facing outwardly towards a medial side and a lateral side and providing a smooth transition between the sidewall surface of the chamber and the reinforcement member , the sidewall surface of the fluid-filled chamber forming an exposed sidewall of the sole structure extending from the chamfered surface of the reinforcement member to the second surface of the fluid-filled chamber ; wherein the chamfered surface defines an outer surface of the article of footwear and the sidewall surface of the fluid-filled chamber is exposed along an entire periphery of the reinforcement member , wherein the fluid-filled chamber has a shape that substantially extends from a forefoot region to a heel region and also from the lateral side to the medial side , thereby corresponding with a general outline of a foot; wherein the reinforcement member only extends around the heel region of the fluid-filled chamber and along the medial and lateral sides of the fluid-filled chamber up to a midfoot region , whereby the reinforcement member does not extend around the whole periphery of the fluid-filled chamber . a fluid-filled chamber that encloses a pressurized fluid, the fluid-filled chamber having a first surface, a second surface, and a sidewall surface, the first surface being oriented to face toward the upper , the second surface being located opposite the first surface and oriented to face away from the upper , and the sidewall surface extending (i) between the first surface and the second surface and (ii) around at least a portion of the fluid-filled chamber ; and wherein the fluid-filled chamber comprises a reinforcement member being formed from a material having a greater modulus of elasticity than a material forming the fluid-filled chamber , the reinforcement member including a chamfered surface facing outwardly towards a medial side and a lateral side and providing a smooth transition between the sidewall surface of the chamber and the reinforcement member , the sidewall surface of the fluid-filled chamber forming an exposed sidewall of the sole structure extending from the chamfered surface of the reinforcement member to the second surface of the fluid-filled chamber ; wherein the chamfered surface defines an outer surface of the article of footwear and the sidewall surface of the fluid-filled chamber is exposed along an entire periphery of the reinforcement member , wherein the fluid-filled chamber has a shape that substantially extends from a forefoot region to a heel region and also from the lateral side to the medial side , thereby corresponding with a general outline of a foot; wherein the reinforcement member only extends around the heel region of the fluid-filled chamber and along the medial and lateral sides of the fluid-filled chamber up to a midfoot region , whereby the reinforcement member does not extend around the whole periphery of the fluid-filled chamber . <EOS>