A new method is described for measuring tire cornering stiffness and relaxation length under transient conditions. The hub of the test tire, which is riding atop a rotating drum, is attached to a horizontal beam that is hinged at its other end to permit free lateral motion of the tire. When the tire is given a lateral pulse it oscillates at its natural frequency about the position of zero steer angle. Both cornering stiffness and relaxation length of the tire can be calculated from the frequency and logarithmic decay of the resulting oscillations. Results of this “pendulum” test are compared with those from steady‐state tests and from the sinusoidal steer angle test, which has been the conventional one for measuring transient tire characteristics. Advantages of the pendulum test are pointed out.