Over the last decade, the log transportation sector of forest industry in Canada has improved productivity by adding more axles to the trailing system of additional 5-axle configurations, to the detriment of vehicle mobility. If payload capacity is increased by adding a drive axle to a tandem drive group, the resulting tridem drive system will provide both productivity and traction benefits. However, this changes the handling performance of the vehicle, specifically the steering response during low-speed, tight turns. To determine the tridem tractor's steering response, a testing program was undertaken to validate computer simulation models, and following validation these models were used to determine the appropriate vehicle parameters to ensure acceptable handling on both high- and low-friction surfaces. Recommendations for vehicle parameters are presented in terms of the respective weights and dimensions regulations for the provinces of British Columbia and Alberta