Rolling resistance, also referred to as rolling friction or rolling drag, is the primary force that opposes the motion of a wheel, or other object, when it rolls on a surface. Because of rolling resistance, any wheeled vehicle coasting on a level surface will gradually slow down and come to a halt.
Major factors determining rolling resistance are the deformation of the wheel while rolling, the deformation of the surface resulting from the rolling, and the diameter of the wheel. That is, smaller deformation and larger diameters result in less rolling resistance.
Thus, a vehicle with steel wheels running on steel rails will roll much further, typically several times further, than a vehicle having the same mass (or weight) but having rubber tires that run on asphalt because of the great rigidity of steel and consequently its much less deformation than those of rubber and asphalt.