An adjustable airless tire system includes supporting rods connecting with walls of a tire and a metallic hawser loop, which transfer a load of a vehicle from a ground contact surface of the tire to whole walls of the tire. A sensor detects a tension of the tire and a variation of the tension during driving. A control component adjusts the tension of the tire according the load of the vehicle and the road conditions to improve its oil saving, comfortability, controllability and safety. A rim of a wheel keeps an appropriate distance from the tire to limit the maximal level of downward movement of the supporting rods, and support the load of the vehicle if the tire is overload or the supporting rods lose their function. A curved tire forms closed space between the tire and the rim of the wheel to prevent sticking of foreign objects between them.