A test method is described for measuring energy losses in rolling, using the damped oscillations of a pendulum that makes a rigid cylinder roll backwards and forwards across a rubber block (Gent et al. U.S. Patent No. 6,494,076 131, The Goodyear Tire and Rubber Company, December 17 (2002)). The mechanics of small swings, in which the displacement of the contact patch is smaller than its length, are shown to be different from those governing swings of larger amplitude. Thus, starting with relatively large swings of the pendulum, the amplitude of oscillation decays initially at a constant rate and then changes to a decreasing rate as the swings become small. In principle, the two processes provide separate measures of the energy losses in rolling. The proposed test method may be useful for studying the effects of the surface features of tire treads and road surfaces on tire rolling resistance, in addition to characterizing the dissipative properties of rubber compounds.