Super Bell introduced its first dropped tube axle in 1975 and has since gone on to develop both tube and I-beam axles, including aluminum I-beams. The I-beams are available drilled or un-drilled with the ends filled or standard. Cast from high-strength ductile iron, Super Bell's I-beams are designed to accept '37-48 Ford or Econoline spindles. The company's 2-inch-diameter tube axles accept the early Ford spindles and are available in standard widths of 46 1/2 and 49 inches kingpin-to-kingpin center with perch centers of 36 1/2 or 34 inches, as well as perch boss thicknesses of 2 or 2 1/4 inches, though custom axles can be ordered with widths between 42 and 49 inches, a choice of drop distances, and spindle applications, including Chevy. For those wanting something a little different, Super Bell's aluminum I-beam comes in a 4-inch drop, with 34-inch perch centers, 2-1/4-inch perch bosses for Ford spindles, and a 29-inch spring. It's available fully polished or just highlighted, and comes with a drilled option, including the neat oval drilled version.