TRANSPORT . TIPS FOR TRADESMEN.
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Particularly Addressed to Those Who are Replacing Horsed Vehicles by Motors or Contemplating So Doing.
T. HE STATEMENT may sound curious, but the fact remains that., in the great majority of instancee in which commercial motor vehicles fail to give full satisfaction, the cause is. traceable to the possession by those vehicles of qualities in a sense exceptional.
The Abuse of Qualities.
It is not intended by this to convey the impression that it is the vehicles of unusual merit that are the. subjects of failure, but rather that the failure, when it occurs, is due to the abuse of some quality inherent to the majority of motor vehicles, but not shared by other transport systems. When. the trader who has previously used horsed carts contemplates the adoption of motor vans for delivery purposes, a number of advantages of the new method are pointed out to him. Attention is called to the speed capabilities of tliii motors, to their reserve of strength and of power, to the fact that they do not tire and, therefore, can be kept at work for very long hours day after day. In practice, he finds that these claims are perfectly sound, but the risk—and it is a considerable one--is that he will be zo much impressed by the advantages named, that he will not realize the inadvisability of making consistently the fullest possible use of his new capabilities.
Speed and Power.
. Practically every motor vehicle is capableof travelling at a somewhat higher speed than is desirable unless the conditions, are just about ideal. Leaving legal considerations out of the question, consistently high speeds are still apt to prove expensive for many reasons. One is that if the roads, are imperfect, the vibrations due to their imperfection are magnified if the speed is high, and the material of which, the chassis; is made tends to lose quality as a, consequence of this constant vibration. Metal which is continually being subjected to stress, constantly applied and removed, after a time becomes tired and less capable of withstanding those stresses than it was originally. The final result may be a fracture, immediately caused by some stress which, taken alone, should not have been excessive.
High speeds, moreover, mean high consumption (.0 fuel and oil per mile. Their effect on tyre wear. is very considerable, partly because the blows to which the tyres are subjected are more violent than they would be at moderate: speeds, and partly because the maintenance of a very high average speed must mean at times the very sudden application of the brakes. Thus, while we recognize that every increase in speed means an increase in the useful work that can be done in a day, which in turn means a reduction of .standing charges per mile run, we must also recognize that high speeds will involve entries on the other side of the balance-sheet.
The fact that the engine power of a motor vehicle is almost always adequate to enable quite satisfactory speeds to he maintailied, even under a load considerably greater than that contemplated is in a sense an encouragement of overloading. If we carry, say, 3 tons of useful :e.aei: on a vehicle designed for 2 tons, we increase its useful working capacity by 50 per cent., and, so far as fuel and other sapplies are concerned, we attain this result at very little additional cost. Consistent overloading is, however, a
very .expensive hobby. When a load is put on any metal structure, a certain amount of temporary dis tortion in that structure takes place, but, if the load is not excessive, these slight benclings or stretchings are purely temporary. As soon as the load is re moved, the structure goes back exactly to its original. shape. If, however, the load is very excessive, we get the same sort of effect as that which occurs when a light spring is stretched too violently. We know in that case that, when we let go of the spring, it does not close up again, but remains permanently distorted. The same thing happens in a smaller degree to a structure like that of a motor vehicle_ If, because the loads are too big, the stresses are also to big, then the structure becomes permanently strained, the metal loses quality and accelerated depreciation sets in.
It will be apparent that only occasional overloading may lead to a result of this kind. Systematic overloading is certain -to do so, but even the latter is quite common. In other words, let us say a 2 ton vehicle is presently convicted of failure to carry its normal load with proper reliability, because at some stage its nature has been spoilt by making it carry a load of perhaps twice the size. A failure of. this kind may be said to be due to. the rather exceptional quality of the motor vehicle, inasmuch as it can, at a pinch, be made to develop more power, and to deal with heavier leads than were ever intended to fall to its lot.
Next we have the valuable quality of a motor vehicle which enables it. to go on working hour after hoar under full load, and yet to remain just as fit for its work at the end of a day or week as it was at the beginning. This is a merit which is particularly appreciated by those who have, hitherto, had to depend on horses, and, for that reason, the quality is all the more likely to be abused. In times of very special stress, it may be abeolutelei necessary to keep a vehicle at work practically day and night for days or weeks on end. The ability to do so may make a tremendous difference to the vehicle owner's business as a whole. The thing may, therefore, be worth while from the point of view of trade, but from the standpoint of the chassis it is bad policy, and the vehicle must net be blamed if its life proves short. By all means, let the daily hours be long, provided that the proper supervision is received on the return of the vehicle to the garage. The necessary cleaning must not be skimped, and a look round may reveal the slight loosening of a nut, or some; other trivial matter which, if undetected, might,. later on, lead to a serious breakdown. Every vehicle should also be given its half-day in the shops every week for more thorough examination and adjustment, and, at least once a year, it should be ;subjected to a thorough overhaul, being kept off the road for a week or so for this perpose. If all these precautions are observed, long workin.a hours under full load will do no harm. They will, in fact, be found to represent the conditions that are consistent with the lowest costs of haulage per ton mile. It is when the appa
rent willingness of the motor to go on working for ever is made the excuse for failing to give it .the little attentions which it really requires; that the abuse of a very valuable quality becomes one of the commonest causes of rapid depreciation, high repair bills, and general dissatisfaction.