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Moulton: A more pleasing bicycle

The bicycle is by some measures the most efficient form of transport yet engineered, yet its design hasn’t fundamentally changed for 130 years. If cars were like bikes, we would still drive Model T Fords (though they would have carbon fibre starting handles, as one bike designer quipped). A simple drawing of a bike made in 1915 would look similar to one made in 2015. Unless it was a sketch of a Moulton. Dr Alex Moulton CBE was an engineer who made “probably the biggest single contribution to the advancement of the art of bicycle design in the 20th Century”. He didn’t even work for a bicycle manufacturer, although he had to become one when his ideas proved too radical for the industry.

Moulton graduated in engineering from Kings College, Cambridge. During World War Two, he worked at Bristol designing aero engines and went on to design the suspension of the original Mini and other cars for BMC (the British Motor Corporation, which became British Leyland).

The Suez crisis of 1956 and the subsequent rise in petrol prices got Moulton out of his car and onto his bike. He cast a critical eye on what was available and questioned why bikes looked the way they did. He didn’t think it was at all natural to have to cock your leg over the top tube to get on or off a bike. He disliked the need for different sized bikes for different sized people, and was critical of the bicycle’s load carrying ability. If he could solve these problems he could “…produce a bicycle which was more pleasing to have and to use”.

It had been a long time since the bicycle had fundamentally changed. The dandy horse and bone shaker had evolved over the first half of the Nineteenth Century, until by the1880s the state of the art was the penny farthing. This was ubiquitous enough to be known as the ‘Ordinary’. It had what now seems an extraordinary arrangement where the pedals were attached directly to its 60-odd inch diameter front wheel. Without gears, the only way to make the penny farthing travel further with each rotation of the pedals was to have a bigger front wheel. It was a long way up to get on and a longer way down to fall off.

Everything changed when J.K. Starley set out “to design the lightest, strongest, cheapest, most rigid, most compact and ergonomically most efficient shape the bicycle frame could be”. It turned out this shape was the diamond frame nearly all bicycle still have. His ‘Rover safety bicycle’ of 1885 also popularised the arrangement we have today of two similarly sized wheels, the front being steerable, the rear being driven by a chain. Of course bikes have moved on since Starley, but with refinement rather than revolution. Pneumatic tyres, multiple gears and more efficient brakes have made bikes better if not so very different. And the diamond frame has been made out of different materials from wood to steel, from aluminium to carbon fibre and back again.

Moulton’s experiences working on the Mini taught him that wheel size had a “tremendous effect on the architecture of any vehicle”. And he was immediately drawn to small wheels, wryly noting that apart from tractors (and bikes) the wheels on vehicles got smaller as they got more advanced. One of the important factors that limits the efficiency of a bike is ‘rolling resistance’ – the force resisting the motion of a tyre as it rolls forward on the road. Most bicycles still had a wheel size of around 26 or 27 inches and it was accepted that a big wheel met with less rolling resistance. Using his favoured method of looking at fundamentals, making calculations, testing and observing, Moulton came to the almost heretical conclusion that the dominant factor in rolling resistance was not wheel size, but tyre pressure. If the tyre pressure was higher the tyre would deform less as it rolled along. Less energy would be wasted pushing down into the ground and more spent moving forward. Higher pressure meant you could have smaller wheels, which meant a bike could be nippier (to use an unscientific but descriptive term). However one disadvantage of small, high pressure tyres was that the ride felt bumpier. So Moulton thought suspension was essential “in any vehicle that carries a human” and used all the experience of his automotive designs and his family’s rubber firm to produce a front and rear suspension system. Although he spent the late 1950s experimenting with a monocoque frame and designs that looked like the Italian scooters of the period, he found them noisy and awkward to produce. His eventual solution he dubbed the “F frame”.

This didn’t look like what others thought a bike should look like. But Dr Moulton was adamant its design was not a matter of style. In a talk he gave over 20 years later he said, “Styling in the design sense is actually about evolving an image of something else in the mind of the observer. In the case of my bicycle, a pure engineering object, I am not wanting to evoke an image of anything; only to reveal its hopefully harmonious form of fitness for its purpose”.

Moulton was an engineer, not a manufacturer. George Wilson however was the Chairman of Raleigh, the world’s biggest bicycle producer. He saw Moulton’s first designs and declared them to be the most interesting thing he had seen in his professional life. Moulton and Raleigh worked closely together and prepared to put the design into production, but at the eleventh hour Raleigh pulled out. So, Moulton Bicycles Ltd was started in the grounds of the family home in Bradford-upon-Avon. The bike was launched in 1962 with 16 inch wheels, front and rear suspension and luggage carrying capabilities.

Critical acclaim and commercial success followed and the bike and its successors went on to became an icon of the swinging sixties – a mini bike to go with mini cars and mini skirts. Despite doubling the size of the factory it was impossible to meet demand, so a deal was struck with BMC, Moulton’s erstwhile employers to build the bikes in Kirby near Liverpool. Moulton found his company had become the second biggest bike builder in the country (after Raleigh).

Moulton did not see his design as a either a novelty or a highly specialised bike. He was keen to prove it could compete with every type of bicycle including racing and touring. Indeed one of his later machines would be called the APB (All Purpose Bicycle). From the start he encouraged riders to set new records. No less a rider than Tom Simpson (the Bradley Wiggins of his day) rode and admired the bike. If the UCI (cycling’s notoriously conservative governing body) would have allowed it, Simpson said he would have ridden it in the Tour de France.

Raleigh seeing the sales success of the design they had turned down, launched a superficially similar competitor. Small wheeled “shoppers” such as the R(aleigh) S(mall) W(heel) 16 of 1965, eventually outsold the originator. They may have looked similar, but they ignored the conclusions Moulton had drawn from his research – the RSW 16 had low pressure ‘balloon’ tyres and lacked suspension, so performed poorly. Moulton would later criticise this approach saying, “We’re not interested in engineering innovation, we’re simply fashion driven”. Meanwhile poor build quality by BMC affected Moulton’s own reputation and in 1967 (the year Tom Simpson tragically died in the Tour de France) Moulton accepted an offer from Raleigh to buy the business, which at least gave him more time to work on other projects. He continued as a consultant even if Raleigh continued to ignore many of his ideas and warnings, particularly about structural problems that resulted from a cost decision to leave out the suspension from one model. There were several further versions of his bike produced, but after dwindling sales, production ended in 1974 and Moulton and Raleigh went their separate ways, with Moulton producing a ‘Y-Frame’ refinement of his concept.

Moulton went back to his drawing board, got control of his patents and came up with a major new idea he described as the ‘space frame’. This included the key features of his original bikes, but with a frame that seemed inspired by the architecture of electricity pylons, or the geodesic designs of R. Buckminster Fuller. Architect Norman Foster nominated Moulton’s space frame as the greatest piece of 20th Century British design and said, “Like other engineered objects that I find exciting, its appearance and performance are indivisible – it has a kind of sparse beauty”. Moulton explained his thinking thus, “If you look at space vehicles they are all made in a triangulated space form which has been the basis of my designs ever since.”

A quality much sought after in bicycle frames is stiffness – so more of the energy a rider forces down through the pedals is translated into forward motion (though a very stiff bike might be very uncomfortable to ride). A conventional frame is essentially a 2D object, The space frame is most definitely three dimensional and Moulton emphatically stated it to be, “…a stiffer lighter structure than is possible with a single tube” (i.e. a conventional frame).

The construction of the new frames was intricate and time consuming. One frame builder explained a typical frame might have 11 welds, he reckoned one of Moulton’s later designs had 200. They would never be a mass market item, instead Moulton positioned them as high quality, low volume products and hand built them once again in the small factory in the grounds of his house, though for trademark reasons for a number of years they would be called “Alex Moulton”. A more affordable versions of the bikes were produced by Pashley.

Moultons are still unique. There are other small wheeled bikes around, none ride like a Moulton. It is a common misconception that they fold like a Brompton does. They don’t although some are ‘separable’ – they can split into two parts to make transporting and storing them easier. James Dyson reckoned, “Good design is about how something works, not just how it looks, which is why I like the Moulton bike so much.” But New York’s Museum of Modern Art reckoned it looked pretty good too and put a 1983 AM2 bicycle into their permanent collection

Dr Alex Moulton died in 2012 aged 92. To the very end he was refining his design and working on a new model code named MDev 90. It would be wrong to think of him as an eccentric. The cycling world might have its share of mavericks, but Alex Moulton also continued to design for the hard nosed automotive business. All of his meticulous design work was backed up with calculations and original thought. He was in short, a great British engineer who built many wonderful things.


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