Velocette: The Three Twins Roarer, Model O and LE: An In-depth Engineering Analysis of These Twin-cylinder Velocette Motorcycles

The Veloce company is well regarded for producing some of the best single-cylinder motorcycles in race form and for private use. It is not so well known that Veloce Ltd also produced some twin-cylinder machines: the Roarer, for racing, and the Model O for production. These bikes had many engineering features in common, such as twin contra-rotating crankshafts, inline cranks, shaft drive, and swing arm rear suspension. The supercharged Roarer was never raced because of the advent of war; this also put paid to the development of the Model O, which would have been the first so-called ‘Superbike.’

After the war, the Goodman family, which owned Veloce Ltd, focused on the production of a ‘Motorcycle for Everyman’: an idea that had featured in the company’s production bikes since its formation. Ideas embodied in the Roarer and the Model O were drawn on to produce the twin-cylinder LE range of motorcycles; these, however, were not well received by the motorcycling public, and many blame the production of the LE for the eventual demise of the company.

The purpose of the book is to present, from an engineering perspective, an analysis of the Roarer and the Model O, comparing and contrasting the methods adopted by their designers to meet the different design specifications of these bikes, and to illustrate how the ideas developed in this exercise appeared in the LE range of motorcycles.
The authors, Brian Agnew and Ivan Rhodes, met in the 1960s when Brian worked at Rolls-Royce Derby. They spent their weekends tinkering with motorcycles, and both have an intimate knowledge of the Velocette twins both from their time spent together and from their personal projects.

Brian Agnew was employed at Newcastle University from 1984, teaching and undertaking research in thermodynamics and automotive engineering. Prior to retiring in 2015, he was a Fellow of the Institution of Mechanical Engineers and a member of ASME and SAE.
Brian has written over 200 technical papers and two well-read book chapters, as well as contributing articles in the LE club magazine.
Having been a serial Velocette motorcycle owner since the 1960s, he has owned nearly every model from the 1940s, and rebuilt every model of the LE range. He is a long term member of the Velocette Owners Club and the LE Club, and was at one time Chair of the Northumbrian Section of the VOC.