Using Reduced Tire Pressure for Improved Gradeability – A Proof of Concept Trial

ABSTRACT Pope & Talbot Ltd., Arrow Lakes Timber Division, Nakusp, B.C. having no alternative options constructed a forest road with adverse haul grades up to 16%, to access a harvesting area. The company did not know the exact limitations of the adverse haul grade, but it did plan to use highway sized loads on this off-highway haul, thus sacrificing some productivity. When the road was completed and the right-of-way wood was to be hauled, it was found that the self-loading log trucks were unable to climb the grade without the assistance of a skidder despite the reduced load size. Since the road was intended for long term access and no alternate route was possible, Pope & Talbot sought the advice of the Forest Engineering Research Institute of Canada (FERIC) on safe and economic alternatives to improve log truck gradeability on the adverse road section. Based on a theoretical analysis of tractive ability, a field trial was conducted in October 2000 to demonstrate log truck gradeability improvement resulting from tire pressure reduction.