The AM Series of Moulton Bicycles

The AM series of bicycles was launched by Dr Alex Moulton in 1983. Initially it consisted of just two models – the ‘town’ AM2 and the touring or sporting AM7. As with all AM and APB models, the number after the letters indicates the number of gears. The AM2 used a Sachs 2-speed hub gear combined with a coaster (back-pedal) rear brake. A small backward movement on the pedals switched from high to low gear and vv, and further backward movement operated the rear brake. The AM7 used a conventional derailleur gear, albeit fitted with special cogs for the smallest number of teeth, so as to achieve appropriate gearing for the small (17 inch) wheels. The touring model was fitted with slightly lower top gear than the sports model (10 tooth sprocket instead of 9 tooth). The most novel features of the AM series are:

  • Unique 17 inch wheels, radially spoked at the front, fitted with 17 inch tyres. Originally the tyres were manufactured by Wolber, but now suitable tyres are available from Bridgestone and Continental. Life is good given the relatively small size, but obviously is less than for larger wheeled bicycles, and the low volume production and lack of competition means tyres are no cheaper than good quality tyres of larger diameter. Early tyres were thought by many to be rather puncture prone, although this does not seem such a problem now. Since the tyres are unique to the AM series (and now the Bridgestone Moulton, which, however, is only available in Japan at the time of writing), availability is also very restricted, and long distance tourists will wish to take spare tyres and tubes with them. Although the use of these special wheels and tyres does have its down-side, as described, they are very rigid and light wheels, inertia is low and the rolling resistance of the tyres is very low. Update: Although superficially similar to the Wolber, the Continental tyre was in fact significantly different in design. It too has now been withdrawn, but it is reliably reported that Schwalbe have introduced a version of their Stelvio narrow, high pressure tyre in this size.
  • Front and rear suspension. The rear suspension is very similar to that fitted to the earlier Mk 3 – ie triangular rear forks, pivoted behind the bottom bracket and pressing against a rubber ball in compression against the seat tube. The front suspension uses a relatively complex system of leading links and a conventional spring concealed in the head tube.
  • Frame construction from very small diameter Reynolds 531 tubing in a space frame formation, giving a light and exceptionally rigid frame. The frame can be separated into two parts at a kingpin. Cables are split via connectors prior to separating the frame into its two parts.
  • Optional high-capacity rear carrier – similar to that on earlier Moultons, but this time intended to take a soft bag. The carrier is fitted after removing a small U-tube mounted behind the seat tube. An optional front carrier is also available, although this should only be used for light loads. Paul Lund has produced what he calls the Packhorse carrier, which mounts at the front and will take small pannier bags, and which has less effect on the handling than the standard AM front carrier when loaded. Some riders find the AM front carrier disconcerting as it hides the front wheel, and does not turn with the front wheel.
  • A special ZZipper fairing is available to fit a modified front rack, which provides streamlining. Although very effective, the result of fitting this fairing can be disconcerting in high cross winds, and it does generate noise also.