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Paradoxically, the next step in wheel evolution was the disc one, which bears more resemblance to the initial solid designs. As with many other things in our history, the change was prompted by lower costs as the steel disc wheels were cheaper to make. The rim could be rolled out of a straight strip of metal, and the disc itself could be stamped from sheet metal in one easy motion. The two components were welded or riveted together, and the resulting wheel was one that was relatively light, stiff, resistant to damage, easily produced in mass quantities, and most important, cheaply produced.