HINTS FOR HAULIERS.
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An Occasional Chat on' Subjects and Problems of Interest to Those Who are Engaged, or About to be Engaged, in Running Commercial Vehicles for a Living.
THE method of arriving at the results which are set out in the accompanying tables of running costs has been fully discussed during the last fortnight and no further explanation is, therefore, necessary. It is important, however, to understand that the figures given are not universally applicable. They are not even to be taken as applying to any individual case. They are based solely on average results of working which has been communicated to me from all over the country. I shall not lose one halfpennyworth of my self-conceit if I get a letter from a reader to say that he can improve upon these figures. I shall not even.hand out any bouquets to that reader. My
only retort will be, "And so you ought." .
The fact is that wherever there has been a doubt, wherever results have appeared too optimistic and too much in favour of the motor vehicle, I have judiciously pruned them to suit the average more generally achieved, for it is no part of my business to hold out too rosy a prospect to any intending user or haulage contractor. I believe a careful user driving his own vehicle, or a man who has in his employ conscientious good drivers, can regularly show figures of cost which are a considerable improvement on those which are given in these tables, and he is not to be particularly)eompliniented upon his achievement. On the other hand, I shall be equally unperturbed by the receipt of sarcastic letters from readers inviting me to present them with the name and address of the maker of the vehicle which will show such good results as I have tabulated. It is quite easy to make a lorry cost more to run than what I have stated it will -cost. In many of those cases, however, it 'willbe almost as easy to reduce those figures of cost to the same as my own.and even better, although there may be instances where even the quite ordinary results which I have achieved on paper may be impossible ofapproach in actual fact. These cases, however, will be few and far between, and their existence will generally be traceable to some particular circumstances in which the user or the vehicle is involved.
These remarks in respect of averages do not apply in the case of pneumatic-tyred vehicles of a capacity of from one ton and upwards. No such averages will, in my opinion, be available this side of 1923 at least,and in the case of the heavy vehicles until much later than that, for experience has shown that little reliance can be placed upon the results of selected few vehicles. Prop ef averages can only be ascertained after at least a couple of years' use, and, invariably, the sta,tistics-must be collected from hundreds of users. It is to be confessed, therefore, that, in calculating the costs of running for these large pncumatic-tyred vehicles, I have had to exercise a little of what is generally called "intelligent anticipation." In trying to arrive at some reasonable figures in connection with these vehieles, I have met with several difficulties, not the least -being the apparent indecision of manufacturers as to the right size of tyre to employ. For instance, in considering the cost of tyres only, for a one ton pneumatic (and I am not, in this case, concerned with the Ford), I found variations in cost of from. 2.50d. to nearly 5d. a mile. The figure which I have given, 3,10d., has been taken as representing what might be expected in view of the tyre sizes selected by the majority of manufacturers.' The more expensive ones I have decided as being in the natureof luxuries. Time and experience may prove me to be wrong.
In considering the wear and cost of pneumatics, I have adopted the following expedients : In every case I have reckoned on a spare cover and tube so that,
with a vehicle having four pnenmatics all of same size, I have calculated on five complete tyres. I have assumed a mileage of 5,000 for the covers and 10,000 for the tubes, and have addeda little extra for cost' of vulcaniling and repairs during the life of the tyres. Where six tyres are used, i.e., singles on/ the front wheels and twins on the rear, I have reckoned on seven covers and seven tubes, and have calculated the mileage on the same basis. Where there are tyres of different sizes front and rear, then I have had to take six complete tyres, three for the front and three for the rear, calculating the mileage costs in the same way. In view of the fact that makers of what are now termed " giant " pneumatics claim much greater mileages for their products than have hitherto been deemed possible with pneumatic tyres, I have, for these big tyres, assumed a mileage of 7,000 per cover and 12,000 per tube. I have taken as a means of selecting these giant tyres from which extraordinary
mileage may be expected, the actual cost of the tyre itself, since I have found on investigation that there. is a strong line of demarcation in that respect which becomes apparent with about 35 in. by 5 in. tyres.
It will be apparent that, so far as our present knowledge goes, heavy vehicles with pneumatic tyres are going to cost more to equip and more to run. The cost of a pneurnatic-tyred chassis is more than that of a solid-tyred machine, and replacements will be colleCtor more frequently. It is not possible, so far as our present information goes, to offer more than an approximate estimate of the extent to which maintenance costs, will be reduced if •pneumatics are used. In any case;this must largely depend upon the individual user and driver, and particularly upon his ideas of the pressure to which tyres of this type must be inflated. It is not altogether wise, in my opinion, merely to follow the 'advice of the type maker. He is concerned in the first case with the life of his tyres, 'and not largely with that of the chassis. He. will,
therefore, be inclined to advise pressures which Might be too high to effect the improved maintenance which we look for where pneumatics are used.I have, howeverNaken.it upon myself to assume an improvement of 25iper cent. in maintenance costs. I have not corrected at all the figures for fuel consuMption, oil consumption or depreciation, although we are, perhaps„'naturally .assured,by tyre makers that such improvementa may be accepted,. Personally, I think pneumatic tyres will only show to advantage in such cases where they will allow of a greater weekly mileage being run by the vehicle to which they are fitted, as compared with a similar machine on solids. This will only Ile the case where the roads which Are continuously traversed are poorly surfaced, and where it would not be good. policy to run the vehicle at high speeds on solids, but where the better cushioning effect of pneitmatics would permit such speeds. In other words, I am assuming that the owner who fits pneumatics looks to see their effect in reducing the.
incidence of his standing charges. THE SKOTCH.