The interest in improving vehicle fuel economy has prompted the development of a computer model to predict the power loss of a rolling tire. This model will allow rapid evaluation of the effects of various tire geometric and material properties on the tire power loss. This work describes methods of measuring the thermal conductivity of tire materials, which is just one of the data base inputs required by the model.At the outset, two criteria were established for selecting the thermal conductivity measuring instrument. It should 1) allow the testing of small samples removed from a tire and 2) allow the measurement of thermal conductivity at different temperatures. The latter would allow evaluation of the temperature effect on thermal conductivity, something which is not well reported in the literature.A survey of the available equipment was made, an instrument was acquired, and an evaluation/development program was initiated. Several instrument deficiencies were noted and are reported, along with the modifications made to reduce or eliminate the effects of operating environment and operator technique on the results measured. Some auxiliary equipment needed to help reduce variability of the results is also described. Values of the thermal conductivity of some typical rubbers are given.