Schwinn Bicycle Company a separate deal with the China Bicycle Co. (CBC) to produce bicycles to be sold under the Schwinn brand. In retaliation, Giant introduced its own line of Giant-branded bikes for sale to retailers carrying Schwinn bikes. Both Giant and CBC used the dies, plans, and technological expertise from Schwinn to greatly expand the market share of bicycles made under their own proprietary brands, first in Europe, and later in the United States. By 1990, other United States bicycle companies with reputations for excellence in design such as Trek, Specialized, and Cannondale had cut further into Schwinn's market. Unable to produce
Racing bicycle using a "main triangle" with three straight tubular shapes—the top tube, down tube, and seat tube. These three tubes, and other parts of the frame, need not be cylindrical, however, and many racing bicycles feature frames that use alternative shapes. Traditionally, the top tube of a racing bicycle is close to parallel with the ground when the bicycle is in its normal upright position. Some racing bicycles, however, have a top tube that slopes down towards the rear of the bicycle; the "compact" frame geometry was popularized by Giant. Frame manufacturers are free to use any material they choose in