In 1956, the Suez Crisis caused a shortage of gasoline in Britain and the introducing of rationing. (Don't know about it? Watch The Hour) Engineer Alex Moulton was involved in a number of responses to the high cost of gas: The Austin Mini (he designed the lightweight rubber suspension that helped keep the car small and light) and the Moulton Bike. According to the Guardian,
Moulton’s bike, launched to enormous interest in 1962, was a reinvention of the classical bicycle. He used small wheels, which he argued gave better acceleration and faster overall speeds; springs, again of rubber, and a new feature on bicycles; and a new design of the step-through frame – he considered the top tube of the traditional bike dangerous and an obstacle to dismounting in emergency. The Moulton went through many evolutions from his original “F” frame to later exotic handbuilt stainless steel space-frame machines. However, the success of his design showed their practicality and pointed the way for other small-wheeled and stowable bikes.
Norman Foster called it "the greatest work of 20th-century British design."
The space frame design that I so lust after was not the original; it was developed in the 80s and is still made by his grand-nephew at Moulton Bicycles. It is built by hand and isn't cheap, and isn't mass-produced; Moulton wrote that “Man should make things … Make a profit, of course, but don’t take the money gain as the prime judgment.”
Alex Moulton, dead at 92.