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

HOW TO DRIVE A MOTORCAR respectively 25 and 35 teeth, it is evident that if thos6 teeth are to be made to engage whilst both are revolv- ing the periphery speed (not the actual number of r.p.m.) must be approximately the same. Going back for a moment to our first speed, the gears in mesh meant relative speeds to the shaft of 500 r.p.m. for the little one and of 100 r.p.m. for the big one, and if these speeds were maintained exactly the wheels could be taken out of mesh and brought into mesh again with consummate ease. Now to get into the second gear. We have assumed 25 teeth for the wheel (i) and 35 teeth for the wheel (d), in other words, a proportion of 5 to 7. Now, it is necessary to remember that when we declutch to go out of the first gear the car still goes along, and through the tailshaft forces the primary shaft (m), with its gear wheels, to continue revolving, although naturally they will slow down a little bit by the time the actual change is made. If we assume that the car speed falls down to the equivalent of 90 r.p.m. for the primary shaft instead of .100, then for the wheel (d) quietly to mesh with the wheel (i) it is necessary for the layshaft to run at J x 90 r.p.m., in other word's 126 r.p.m., so as to bring the actual speed of the teeth equal. But when the engine was running we knew that the layshaft and therefore the wheel (i) were doing 500 r.p.m. To effect the 83