Track frame assemblies wherein one assembly provides a multi-section sub-frame that supports a series of idler wheel suspensions. Each section is mounted to pivot laterally from stub axles longitudinally secured to a drive frame. In another assembly, resilient bushings support idler wheel suspension axles to the track frame. The track frame also supports a detachable track tensioner containing idler wheels that facilitate track removal and replacement. A detachable hub at a track drive sprocket/drum further enhances frame mounting. Elastomer shim and air bag assemblies also torsionally control and limit rotation of the track assemblies.