Bicycles and Tricycles : An Elementary Treatise on Their Design and Construction

A BICYCLE or a tricycle is a more or less complex machine, and for a thorough appreciation of the stresses and strains to which it is subjected in ordinary use, and for its efficient design, an extensive knowledge of the mechanical sciences is necessary. Though an extensive literature on nearly all other types of machines exists, there is, strange to say, very little on the subject of cycle design ; periodical cycling literature being almost entirely confined to racing and personal matters. In the present work an attempt is made to g^ve a rational account of the stresses and strains to which the various parts of a cycle are sub- jected ; only a knowledge of the most elementary portions of algebra, geometry, and trigonometry being assumed, while graphical methods of demonstration are used as far as possible. It is hoped that the work will be of use to cycle riders who take an intelligent interest in their machines, and also to those engaged in their manufacture. The present type of rear-driving bicycle is the outcome of about ten years* practical experience. The old * Ordinary,' with its large front driving-wheel, straight fork, and curved backbone, was a model of simplicity of construction, Digitized by CjOOQIC vi Bicycles and Tricycles but with the introduction of a smaller driving-wheel, driven by gearing from the pedals, and the consequent greater complexity of the frame, there was more scope for variation of form of the machine. Accordingly, till a few years ago, a great variety of bicycles were on the market, many of them utterly wanting in scientific design. Out of these, the present-day rear-driving bicycle, with diamond-frame, extended wheel-base, and long socket steering-head -- the fittest -- has survived. A better techni- cal education on the part of bicycle manufacturers and their customers might have saved them a great amount of trouble and expense. Two or three years ago, when there seemed a chance of the dwarf front-driving bicycle coming into popular favour, the same variety in design of frame was to be seen ; and even now with tandem bicycles there are many frames on the market which evince on the part of their designers Utter ignorance of mechanical science. If the present work is the means of influencing makers, or purchasers, to such an extent as to make the manufacture and sale of such mechanical monstrosities in the future more difficult than it has been in the past, the author will regard his labours as having been entirely successful. The work is divided into three parts. Part I. is on Mechanics and the Strength of Materials, the illustrations and examples being taken with special reference to bicycles and tricycles ; Part II. treats of the cycle as a complete machine ; and Part 1 1 L treats in detail of the design of its various portions.