Effect of Wide-Based Single Tires on Fuel Efficiency of Class 8 Combination Trucks

In 2007 and 2008, the Oak Ridge National Laboratory, in collaboration with several industry partners, collected real-world performance and situational data for long-haul operations of Class 8 trucks from a fleet engaged in normal freight operations. Such data and information are useful to support Class 8 modeling of combination truck performance and technology evaluation efforts for energy efficiency and to provide a means of accounting for real-world driving performance within combination truck research and analyses. Some general statistics, including distribution of idling times during long-haul trucking operations, are presented. However, the main focus is on the analysis of some of the extensive real-world information collected in this project, specifically on the assessment of the effect that different types of tires [i.e., dual tires versus new generation wide-based single tires (NGWBSTs)] have on the fuel efficiency of Class 8 trucks. The tire effect is also evaluated as a function of the vehicle load level. In all cases analyzed, the statistical tests strongly suggest that fuel efficiencies achieved when all NGWBSTs or combinations of duals and NGWBSTs are used are higher than in the case of a truck equipped with all dual tires. The results show that the fuel efficiency improvement increases as the number of NGWBSTs on the truck increases, with observed improvements of around 6% when either the tractor or the trailer was equipped with NGWBSTs and more than 9% when both were mounted with these types of tires.