From the 1930s to the 1970s, this was the way high-quality bikes were made: Lugs, which are cast steel sockets, were fitted to the corners of the frame. Next, metal tubes were fitted to the lugs and held in place by brazing or silver soldering.
Schwinn made tandems on their Paramount production line from 1969-1979. The Paramount name was reserved for top-of-the-line Schwinns. Today, this factory continues to make bicycles under the name Waterford Precision Cycles.
In the late 1980s, Alaskan frame builders began experimenting with custom components and design to create a bicycle with a large tire contact patch for greater control on snow; as a result, the fatbike was born.