Abstract: A load extension axle assembly for extending the load distribution of a tractor-trailer includes a load transfer beam with a front end connected by a horizontal trunnion to the trailer chassis and a rear end carried on a tag axle to trail behind the trailer. The trunnion is fixed to the trailer chassis above and between the tandem axle of the trailer. A first log bunk mounted on the tractor supports the front portion of a load of logs. A second bunk mounted on the load transfer beam between the trunnion and the tag axle supports a rear portion of the load. A vertical pivot in the load transfer beam aft of the second log bunk allows the tag axle to swing relative to the trunnion independently of the load to track behind the tandem axle during turns. A sliding sleeve arrangement between the pivot and the tag axle enables adjusting the length of the load transfer beam. A clamp and actuator coupled to the brake system enables the driver to extend or retract the beam.