Tire rolling resistance during the warm-up period plays a significant role in vehicle fuel consumption, a major concern in todays world. In order to better understand tire rolling resistance during warm-up, several passenger tires were evaluated on a 67″ indoor test wheel. A variety of current production tires was tested under various conditions of speed, load and inflation pressure, and the rolling resistance during warm-up was recorded. The warm-up behavior of each tire, being exponential in nature, was characterized by a representative amplitude ratio and time constant. The results presented show the effects of speed, load and inflation pressure on these characterizing parameters.