How To Drive A Motorcar
A Key To The Subtleties Of Motoring

HOW TO DRIVE A MOTORCAR hill be the equivalent of the man trying to move the rock. Neither can accomplish the work in hand. The man, however, with the greater leverage is able to accomplish that which he could not perform before, and similarly, therefore, the engine, if we can provide it with a bigger ratio of leverage, can make the ear climb the hill. It is for neither more nor less than the giving of this different leverage that the gearbox is installed upon a car. Now, in the case of the long crowbar, assuming the man still to exert his given power and to do so at a given speed, the rock will be moved more slowly than it would if the crowbar were, say, only half the length, and the movement where the power is applied to the shorter one carried out at the same speed. Naw, this is exactly the same with the gearbox. Assuming the power to remain the same and the speed the same from the engine, then the resultant power output, if it is to be great enough to take the car up the hill which it could not climb before on the direct drive, must necessarily be slower. We get then the cardinal point that the speed of the gear wheels has to vary considerably with the engine running at a given speed. Now, a little consideration will show that, if the gear change is to be effected quietly and neatly, means must be found for making those gear wheels run at approxi- mately equal periphery speed at the point of contact. Some little space has been devoted to this explana- tion of the need of gear ratios and to make the reason for their necessity easily understood. The full know- ledge of this phase of the gearbox is essential to a good gear change. The Four-speed Gearbox Let us now go through a typical four-speed gearbox and carefully follow the theory of the operations, using the illustration as an aid to the study. First of all we have the wheels (a and b), which constitute what are usually termed the constant-mesh pinions, that is to say, wherever the gear lever is put, at neutral or other- wise, these two pinions are always in mesh and revolv- ing, on the assumption, of course, in the latter case, co