Classic Project: ‘F-Frame’ or Moulton bicycle

Hard as it is to imagine, the general design principle of the bicycle has changed little since the introduction of the diamond frame in 1896. While there have been many challengers to this orthodoxy, the real game-changer was the unveiling of the innovation-laden Moulton bicycle at the 1962 Earls Court Cycle Show.

With its ‘F-frame’, small wheels, front and rear suspension, plus luggage-carrying capability, the Moulton bicycle (sometimes called ‘the Classic’) caused a sensation with both press and public, soon becoming a design icon of the 1960s.

Architect Norman Foster admired its ‘sparse beauty’, while a decade ago it knocked the iPod into second place in a poll of industrial designers asked to nominate ‘an icon of our time’.

Brainchild of British aeronautical and automotive engineer Alex Moulton, it grew out of the desire to produce a bicycle that was ‘more pleasing to have and to use’. Already established in the world of car production – he had designed suspension systems for the Mini – Moulton originally set out to improve on the diamond frame concept, offering the resulting design to the established bicycle manufacturer Raleigh.

When negotiations reached a standstill, Moulton decided to start up his own manufacturing business in Bradford-on-Avon. The initial market reaction to his eye-catching design was so positive that he immediately doubled the size of his factory, which still struggled to keep up with demand. Such was the success of the model that, within a year, Moulton became the second largest manufacturer of bicycle frames in the UK, after Raleigh.

Moulton thought that diamond-frame bicycles, with their big wheels, were slow, cumbersome and difficult to mount. Added to that, they failed to take into account the way modern commuters travelled to work, routinely employing more than one mode of transport. He saw an emerging need for something more compact and convenient.

One of the Moulton bike’s most important innovations is its small wheels, brought in specifically to increase speed. During acceleration, wheel mass is more important than frame mass, rolling resistance is lower for smaller wheels, while aerodynamic drag is reduced significantly by having shorter and fewer spokes. Moulton then went on to develop a range of compatible high-pressure tyres with Dunlop, having reached the conclusion that the performance of small-diameter tyres at high pressure was at least similar to, if not better than, larger variants. The downside of the decreased wheel size was loss of comfort, with the result that Moulton added independent suspension. Meanwhile, the frame, constructed out of large-section tube, and with no horizontal ‘top tube’, created a step-through style that made mounting easier.  

Despite the F-frame giving way to the improved Series 2 and other models, the company came under pressure from aggressive competition in the form of Raleigh’s inferior clone, the RSW16. In 1967, Moulton was taken over by Raleigh in a ‘distress sale’. The firm retained Alex Moulton as a consultant, going on to produce the improved Mark III, which was manufactured alongside the RSW16. By 1974, the game was up and production of Moulton bicycles stopped.

However, the story didn’t end there. Moulton bought back the rights to his design from Raleigh in the early 1980s. According to the Moulton Bicycle Club, this was when he shifted his design focus from the quality mass-market sector to the high-end market with the AM model that is still in production today.

General arrangement of the production version of the Moulton bicycle

Front carrying space

16” x 1 3/8” tyres at 60 psi

Single telescopic suspension with rubber spring

Carrying handle at centre of gravity

Quick-acting saddle adjustment

Rear carrying space

Pivot for trailing arm

Friction damper

Rubber suspension in compression and shear

Plastic chain guard

10 ½” static laden

Axle to axle 44 ½”