A method for estimating an effective radius of a tire of a vehicle, the method may include (i) obtaining sensed information that reflects (a) a distance passed by the vehicle during one or more driving sessions, (b) a rotational speed of at least a wheel that comprises the tire during the one or more driving sessions, (c) values of tire radius affecting parameters during the one or more driving sessions, wherein the tire radius affecting parameters comprise a vehicle speed and at least some other tire radius affecting parameters; (ii) selecting at least one portion of the one or more driving sessions; and (iii) determining the effective radius of the tire of the vehicle based on (a) sensed information gained during the at least one portion, the sensed information comprises values of the tire radius affecting parameters during the at least one portion, and (b) one or more relationships between the effective radius of the tire and tire radius affecting parameters.