This study deals with a tire model for camber thrust and camber torque on an irregular road surface such as road with ruts. At first, tire characteristics with camber angle are measured, for example dimensions of contact area, width, radius of tire and so on. In this research, it is shown to be necessary to those for tire model. The design parameters of brush model are decided. In this tire model, it is considered that the dimensions of contact area is related to the tire camber angle and load, and also the contact pressure is changed according to the contact length, and also the rigidity is changed according to the contact pressure. Finally, it is shown that the calculation result of the tire model has a good expression for the characteristics of camber thrust and camber torque. (C) 2002 Society of Automotive Engineers of Japan, Inc. and Elsevier Science B.V. All rights reserved.