a process and an apparatus for testing the uniformity of a pneumatic tire such as a vehicle tire provide that fluctuations in tire inflation pressure are measured during a uniformity - testing measuring run in which the tire to be tested is rolled against a test surface under a given loading , with force fluctuations occurring at the contact surface therebetween , and in which a compensation value is formed from the measured fluctuations . the compensation value is combined with the measured force fluctuations thereby to eliminate force fluctuation components attributable to fluctuations in the tire inflation pressure .