At first glance, an F-frame moulton, and a spaceframe moulton have very little in common (apart from small wheels, high pressure tyres and suspension, of course)... I mean in the frame of course. One could be forgiven for thinking that Alex Moulton went back to first principles with the spaceframe design.
Well take a look at these photos from Tonly Hadland's gallery. The bicycle shown is a Y-frame, and it is a prototype from the 1970s that nearly made it into production.
One can immediately see that it is a logical progression from the F-frame concept. One can also see how the basic X-shape of the spaceframe is merely a further step away. Of course, the revolutionary step forward in the spaceframe concept is the application of the geodesic structure.
I recall an interview with Alex Moulton where he spoke about the Y-frame. He gave a friend a Y-frame to try out and to see what he thought of it. His friend told him that it was too heavy compared with the lightweight bicycles that were becoming available at the time. This prompted Alex Moulton to search for a lighter structure for his new bicycle. Whoever that man was... we all owe you a huge debt of gratitude.
Tony's pictures of the prototypes in the Moulton museum in Bradford on Avon show the progression in Alex Moulton's design concepts from ideas stage to production.
