MOTORING NOTES

Manawatu Standard, Volume XLV, Issue 138, 15 May 1925, Page 11

MOTORING NOTES

Nowadays when so many thousands of motor vehicles are used in commercial circles throughout Australia and New Zealand, it is essential that the owners utilise that if the best service is to he obtained, that the harmful effects of overloading and excessive speed should be understood. Apart from neglect of the necossary processes of upkeep, the two factors mentioned are most conducive, says Motor Transport (England) to high cost of upkeep. Taking the first of these, overloading, the average owner with his limited knowledge of mechanics, appeals to imagino that so long as the frame, tin axle, a spring, or some other part shows itself able on one, or two, or half-a-dozen occasions to carry an overload -without breaking, no harm is likely to occur if the vehicle is similarly overloaded on future occasions.

But that idea is quite wrong. The illeffects of overloading can be classified as follows:—(1) Immediate, (2) cumulative, and (3) potential. The first class is selfevident at once; the spring, axle or whatnot breaks without delay possibly on the first occasion overloading occurs and maybe at the first bad pothole or other severe: inequality of road surface. The cumulative class of ill-effect is that arising from what is known as the “fatigue” to which all metals are subject; in other words, to the crystallisation of metal that arises from vibration and stressing. Now the metal parts of a motor vehicle are constructed as to their nature, shape and dimensions so as to enable them _to withstand for a long while the vibration to which they will be subjected and to possess a “factor” or margin of safety that will give them a lengthy life before they fail owing to fatigue. But that margin of safety is based upon an assumption that, each part will have to carry a certain maximum toad. Now if that load is frequently or even occasionally, appreciably in , excess of the calculated maximum, f-itigue will occur much sooner. A simple analogy will explain that point,. Take a piece of stout cardboard and bend (i.e. stress) it slightly in both directions; it will withstand thnt treatment tor hours without breaking. But bend it excessively to and fro and it will broak or c'mck after it has been distorted half-a-dozen or a dozen times. The actual occasion of its bending, during which it fractured, was not alone responsible, it was tho cumulative effect of successive bendings. So with an overloaded axle or frame; the actual pothole over which the whee ls passed just before the axle broke was not alone responsible, nor need there be reason for suggesting that, the overload on that occasion was any more excessive than on a dozen other occasions, on each of which, perhaps, a far worse pothole was encountered without ill-effect. Tho third class of ill-effect—Potential --- has close resemblance to the second; but it i 3 not identical. For example, a van may carry a 50 per cent, overload, to-day, without seeming to suffer in any way; but a potential ill-effect may have been brought, into being. It may be dormant for months; consisting, we will say, ot a crack started in a spring bracket,, it may not develop until some day or other the vehicle is again overloaded unduly, though maybe not to such a groat extent as on the previous occasion. Further, a weakness of that kind, pnoe it has ar.seri, is liable to develop at any time, even when normal loads are carried. The canto ot a broken spring to-day may have been an excessive overload twelve moE.ths back. Overloading does not pay not in the end, no matter if it appears to be an economy at first. Even if rlo irechan:.cal part suffers, the tyres will collapse sooner and quite out of proportion to the average overload. One journey of -0 miles with the tyres 60 per cent, overloaded may halve their useful life. With regard to excessive speeds, nereagain we have two or three classes of illeffect. There is the immediate, consisting maybe, of a broken piston, w:r h all tho dire results which than will sometimes bring with it. Then there arc cumulative effects, those which arise from metal fatigue, hastened by repeated overdriving, and showing themselves in a broken, cankshatt or connecting-rod bolt. Others of a like nature aro the rapid wear of tyres caused by the violent braking frequently needed when speeds are excessive, the rapid wearing put of engine bearings because of the heavy stresses to which high speeds give rise, and, altogether different, the excessive petrol consumption. Every motor vehicle has its most economical speed from the standpoint ioE petrol consumption. Above that speea the consumption increases rapidly. It is an elementary fact, though one which is frequently unrealised, that more petrol is consumed at high speeds than at a moderate rate of travel, and yet one nears owners express the view that in travelling a given distance at 25 m.p.h. a motor uses less petrol than in covering the same distance at 18 or 20 n .p.h. because it is running a ;hor',er time! . . , , The work of ear denning is handled expeditiously by a Company in Chicago iU.S.A.) who 12 minutes after an owner has driven his car into the garage, has his vehicle handccl back to him thoroughly cleaned inside and out. ffho capacity of this automobile laundry is a car every 1 1 minutes. This speed work is made possible' by the use c£ special equipment, and adequate personnel. Car 3 are run out to a conveyor which slowly passes the washing attendants, some 32 in number. Each group of worker ha 3 its specialised duty to perform. Waiting rooms are provided in which the owners or drivers may await their spick and span automobile. ihe charge for washing a sedan or coupe type of car is approximately 9s sd, whilst an open body car costs less. An old lady, 71 years of age, recently took out a motor-cycle driving license in France. . .... In the last, seven months of 1924 no fewer than 246 motor-cars and 11 motorcycles were stolen in Sydney, New South Tho duty on motor-cycles imported into Denmark has been advanced by 40 per cent. Fair Motorist: “Really, I didn t hit you intentionally.” Victim: “vVhat have you got that bumper on your car for if you aren’t expecting to hit someone?” The idea of shooting at a tyre to stop speeders was first put into practice by a policeman in 1904. In tho State of Massachusetts the possibility of utilising abandoned roadbeds of steam railways as possible motor routes for commercial use is being considered. The Public Works Department in New Zealand will shortly carry out a similar scheme near Whangarata, in the Frankton County. At Flint, Mich., says the Motor a new law has been instituted which, in part, reads: “It shall be unlawful for any person to drivo an automobile on the streets of Flint whilo being subjected to the embraces of any other person; it shall be unlawful to embrace the driver.” A successful charge of driving to the common danger was recently secured in the North of England against a motorist for a similar procedure. A woman was charged at tho Wanganui Court with a breach of the motor regulations for driving a motor-car in tho Avenue in a manner that, in the circumstances, might be dangerous to tho public. Noel Hogg was similarly charged, but the information against him was dismissed. It appears that the woman was receiving her last lesson in motor-driving from Hogg, who at tho time had not received his license to drive. When near tho Avenue School an accident occurred. A woman was knocked down, and bad an arm broken, while a child in a pram was thrown clear of danger only just in time. The magistrate imposed a fine of £1 with costa.

THIEVES BURN MOTORS. AFTER PARTS ARE STOLEN. EPIDEMIC IN VICTORIA. MELBOURNE, May 1. The epidemic of motor car thieving continue?. The practice of the car thieves is to strip the cars of everything movable, then to set fire to them in lonely placce. Two cars were found badly burned at Donnybrook, and one at Bundoora yesteiTho affair at Bundoora was particularly daring. The ear was taken within 300 yards of the post office. Two men were seen pouring petrol over it but. before the police patrol arrived they hod left in another car