A track system for a ground engaging vehicle such as a tractor is provided. Track systems shown include the ability to maintain existing gear ratios and vehicle speed when interchanging wheels with track systems as described above. Embodiments shown also exhibit improved support of the track system in relation to a vehicle axle that reduces stress problems associated with the axle or related components. Another feature includes pivoting the track system in a way that prevents the track system from rotating 360 degrees around the axle when large obstacles are encountered.