MOTOR AND CYCLE.

Taranaki Daily News, 26 February 1921, Page 10

MOTOR AND CYCLE.

NEWS AND NOTES. As every practical motorist knows, a pneumatic tyre generates heat when running on the road, and all other things being equal, the faster the speed of the car the greater the heat generated. The generation of heat by a tyre, so far from being a disadvantage, is, within the limits, rather a tribute to its shock-absorbing qualities. The heftfc within the tyre is not mainly generated by the actual friction with the roadsurface, which accounts for a relatively small proportion; what does cause heating is the constant flexion and recovery of the tyre walls in their work of absorbing the shocks due to road inequalities. If the tyre did not possess those essential qualities of shock-absorp-tion there would be very little internal heating; but, of course, the car would be very much more uncomfortable to ride in. The nearer a tyre approaches to the solid, the less heat there will be generated. The well-known Australian airman, Mr. Harry Hawker, is now engaged in the motor cycle trade in England, he being interested in a £20,000 company bearing his name. The manufacture of motor-cycles on an extensive scale is the object of the enterprise. Owing to the depression in the American automobile trade, only one out of every five tyre factories is working, and many of these are only operating up ,t.o about 20 per cent, of the maximum output. There are about 240 tyre manufacturers in the United States as against 40—only four years ago—and there has unquestionably been a serious over-production of tyres in that country, resulting in the biggest slump ever experienced in that direction. The modern bicycle frame, as produced by a first-class maker, is one of the marvels of mechanical engineering; but it is so common that the man in the street never gives it a thought. Weighing but eight or ten pounds, it will carry a 12-stone man at 20 miles an hour, over any sort of roads, withstanding bumps, bangs and wrenches, for tens of thousands of miles, and never make a murmer. The material is steel of a quality which, through years of experiment and research, combines toughness and strength in a marvellous degree. The “guage” or tlnckness, of the tubes is so arranged that each part of the frame contains just enough metal, and no more, to give the strength necessary for its own particular job. On the other hand, a frame made by an inexperienced or inferior firm may be too strong in some parts and too weak in others, with the inevitable result that unequal stresses are set up, and the weakest part, sooner or later fails.

A recent test showed that to prevent excessive engine wearing, crankcase oil should be changed at least every 1,500 miles, preferably every 1,000 miles. A new engine that was run 6,000 miles with oil changed at proper intervals, upon being disassembled showed no signs of wear. The same engine, assembled and run 6,000 miles with old oil plus new oil as needed, upon inspection showed a wear of 0.015 inches. Motor manufacturers recommend, for better performance and longer life, that, crankcase be drained every thousand miles, the engine flushed with kerosene and new oil added. Before the war the German made magnets practically held the European market for this necessary fitment for cars, aeroplanes, motor cycles etc. With the advent o-f hostilities, England, France and Italy were hard put for magnetos, which were essential in all branches of motor transport and. aviation. To meet the shortage, several English concerns undertook the making of magnetos, and in the latter stages of the war their efforts were such that they made better magnetos than any previously made and marketed by the Germans. These manufacturers are now “up against” the cheaper produced post war German magnetos which are being rushed into the English market at a price |hat English makers cannot approach. The position now is that the English magneto industry (practically a key one) is faced with disaster unless the English Government and the English motor manufacturers stand Ly the British made article. The growth of motoring in Victoria is told in the latest figures compile:! by the Registration authorities. During 1920 there were 21,000 cars and 12,500 motor cycles registered in Victoria, whilst some 37,000 driving licenses were issued. In December alone, 2384 cars and 1224 motor cycles were registered. These are of course not all rew vehicles, inasmuch as every motor car or motor-cycle has to pay an annual licensing fee.'