Abstract: Method and apparatus for testing tires to measure the rolling resistance generated while a tire rolls under a radial load, the method including the steps of mounting two tires on spindles having substantially parallel axes; wherein the two tires are substantially equivalent and have substantially equal inflation pressures; loading a first one of the tires against a second one of the tires, tread-to-tread, at a predetermined tire-to-tire test load, then measuring a distance between axes of the two tire spindles; rotating one of the tires such that it rotates the other tire; measuring the total torque required to rotate the two tires at a predetermined rotation rate; and calculating the average rolling resistance of the two tires by dividing the value of total torque by the distance between the axes of the two tire spindles. Alternatively measure force at each spindle, equating each force to that tire's rolling resistance.