C42-44836 in. Wide, 6 in. Drop, 6 in. Flat, Stiletto Bosses1-1/2 in. Outside Diameter, 0.120 in. wall 4130 Chromoly Tubing C42-44739 in. Wide, 6 in. Drop, 6 in. Flat, Stiletto Bosses1-1/2 in. Outside Diameter, 0.120 in. wall 4130 Chromoly Tubing C42-44940 in. Wide, 40 in. Flat, Stiletto Bosses1-5/8 in. Outside Diameter, 0.120 in. wall 4130 Chromoly Tubing C42-43836 in. Wide, 6 in. Drop, 6 in. Flat, SPE Bosses1-1/2 in. Outside Diameter, 0.120 in. wall 4130 Chromoly Tubing C42-43739 in. Wide, 6 in. Drop, 6 in. Flat, SPE Bosses1-1/2 in. Outside Diameter, 0.120 in. wall 4130 Chromoly Tubing C42-43940 in. Wide, 40 in. Flat, SPE Bosses1-5/8 in. Outside Diameter, 0.120 in. wall 4130 Chromoly Tubing Precision-machined chromoly axle is TIG welded and spindle bosses are mounted at an 8 degree angle to accommodate spindles. Width dimension is measured from center of tire to center of tire. Drop dimension is measured from bottom of axle to centerline of spindle. Stiletto bosses measure 2" tall and SPE bosses are 1.875" tall.