Abstract: An axle span linkage for adjusting the axle span on a log truck, including front and rear locks pivotally mounted to a bolster pipe receiving the pole of a log truck. The front lock engages a collar mounted on the pole when the rear axle bolster is positioned in a forward orientation on the pole, for orienting the bolster closest to the tractor. The rear lock engages a like collar mounted on the rear end of the pole when the bolster is positioned rearwardly on the pole from the first position. The axle span linkage includes a front adjustable rod attached to the front lock and extending rearwardly for attachment to a pivot arm. A rear adjustable rod extends from the pivot arm to the rear lock. An air cylinder operates the pivot arm to selectively engage the front and rear locks with the respective collars against spring tension. A pole-engaging linkage mounts on the headache rack of the truck rearwardly of the pole-engaging rest.