Bicycle wheel In 2006, Shimano and Hutchinson introduced a tubeless system for road bikes. The rim is connected to the hub by several spokes under tension. Original bicycle wheels used wooden spokes that could be loaded only in compression, modern bicycle wheels almost exclusively use spokes that can only be loaded in tension. There are a few companies making wheels with spokes that are used in both compression and tension. One end of each spoke is threaded for a specialized nut, called a nipple, which is used to connect the spoke to the rim and adjust the tension in the spoke. This
Are Years What? (for Marianne Moore) mobile with wire, shaped like a "V". "Are Years What? (for Marianne Moore)" is signature of di Suvero's monumental early 1960s "open-work constructions." These works utilize cast-off construction materials like chains, metal bars, and ladders. This sculpture is the first that di Suvero built, from beginning to end, with I-beams and using a crane, solely by himself. "Are Years What?" was originally in the collection of the artist, then the collection of Enrico Martignoni of Winnemucca, Nevada. Hirshhorn director James Demetrion first saw the sculpture when it was on display in Brooklyn's Prospect Park. The sculpture was acquired by the