Abstract: An assembly capable of accommodating casters having a different attaching-bolt pitches to a load carrying wheeler is disclosed, which includes two segmented halves of a pair of sleeves each composed of a mouth to receive therein ends of horizontally spaced tubular crossbeams and segmented halves of a caster-attaching block interposed between each sleeve pair. The blocks have a plurality of elongated bolt holes in the direction perpendicular with the axis of the sleeves, laid out end-to-end, so as to accommodate a range of caster-bolt pitches, and at least a pair of elongated bolt holes in the direction parallel with the sleeves' axis, also provided to accommodate a range of bolt pitches for a caster being attached to the base of the wheeler's rectangular framework. The segmented sleeves are made to slide closer or farther away from each other, so that the spacing of bolt holes across the segments can be adjusted to meet a wide range of caster-bolt pitches.