Abstract: An adjustable steering axle includes an outer axle having an exterior surface and an inner cylindrical surface. The inner axle has an outer cylindrical surface, a first kingpin receiving tube provided at a first end of the inner axle and a second kingpin receiving tube at a second end of the inner axle. The inner axle is rotatably received within the cylindrical surface of the outer axle. A first kingpin extends through the first kingpin receiving tube, and a second kingpin extends through a second kingpin receiving tube. A first spindle is rotatably mounted about the first kingpin, and a second spindle is rotatably mounted about the second kingpin. A caster charge pin is attached to the inner axle and provides rotation of the inner axle relative to the outer axle. The adjustable steering axle is desirably used on semi trailers.