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

HOW TO DRIVE A MOTORCAR and the momentary and after effect which such move- ments produce. To start with, then, in the vast majority of gearboxes the work of changing gear consists in withdrawing one toothed pinion from mesh with, another and making another pair of pinions engage. Now, in the writer’s opinion, the man who first put such a contrivance on to a motorcar, more especially with the metals at that date available, was worthy of the mechanical engineer’s equivalent of the Victoria Cross! It was a bold con- ception, and could it have been put to most of the engineers of the present day without the light of the practical proof of its possibilities, it would, in all pro- bability, have been decried as a mechanical abomina- tion. The writer would go even further still and say that it is one, bub the marvellous state of efficiency and success to which it has been brought in the motor in- dustry is so good an excuse for its existence as almost to give the lie direct to the criticism. Be that as it may, however, it is only en passant. This movement which we have to get is obtained by the simple work of pushing forward, or bringing back, the change-speed lever. It is now necessary to con- sider the question of speed ratios and their bearing upon the subject, as that is all that a gearbox is. We have an engine which is capable of a certain torque, or power output, and a car of a good weight to be driven along roads of varying surface and gradient, and with diSerent wind resistances, etc. Now, suppose that engine gives off the maximum power it is capable of producing at 1000 r.p.m. Again, suppose that with the final gear axle ratio, size of wheels, etc., the speed would then be 30 miles an hour on a level road. For the moment let us carry that imaginary engine and car in our minds and take a homely simile to further us on our course of understanding fully the value of gear ratios. Suppose we have a large block of rock which it is desirable to move. We find on trying that it is quite impossible to move it with the hands, and we 82