Bicycle Wheel is Duchamp’s first readymade, a class of objects he invented to challenge assumptions about what constitutes a work of art. Duchamp combined two mass-produced parts—a bicycle wheel and fork and a kitchen stool—to create a type of nonfunctional machine. By simply selecting prefabricated items and calling them art, he subverted established notions of the artist’s craft and the viewer’s aesthetic experience. The 1913 Bicycle Wheel was lost, but nearly four decades later Duchamp assembled a replacement from newly found prefabricated parts and affirmed that the later version is as valid as the original.
Bicycle Wheel is Duchamp's first Readymade, a class of artworks that raised fundamental questions about artmaking and, in fact, about art's very definition. This example is actually an "assisted Readymade": a common object (a bicycle wheel) slightly altered, in this case by being mounted upside-down on another common object (a kitchen stool). Duchamp was not the first to kidnap everyday stuff for art; the Cubists had done so in collages, which, however, required aesthetic judgment in the shaping and placing of materials. The Readymade, on the other hand, implied that the production of art need be no more than a matter of selection—of choosing a preexisting object. In radically subverting earlier assumptions about what the artmaking process entailed, this idea had enormous influence on later artists, particularly after the broader dissemination of Duchamp's thought in the 1950s and 1960s.
The components of Bicycle Wheel, being mass-produced, are anonymous, identical or similar to countless others. In addition, the fact that this version of the piece is not the original seems inconsequential, at least in terms of visual experience. (Having lost the original Bicycle Wheel, Duchamp simply remade it almost four decades later.) Duchamp claimed to like the work's appearance, "to feel that the wheel turning was very soothing." Even now, Bicycle Wheel retains an absurdist visual surprise. Its greatest power, however, is as a conceptual proposition.
from The Museum of Modern Art, MoMA Highlights, New York: The Museum of Modern Art, revised 2004, originally published 1999, p. 87