TRANSPORT TIPS FOR TRADESMEN.
Page 24
If you've noticed an error in this article please click here to report it so we can fix it.
Particularly Addressed to Those Who are Replacing Horsed Vehicles by Motors, or Contemplating So Doing.
T• HE -USER who wishes to get good results from his vehicle will always keep as accurat•te a record as possible of the mileage covered and of the fuel consumption involved. Any sudden change for the worse in the number of miles covered or a gallon of fuel probably indicates a, need for examination and adjustment of the carburetter.. If the change synchronizes with a change of drivers, it is probably a question of their relative skill, and the information given by the records is then very valuable.
Influence of Season on Fuel Consumption • The user should, however, be warned against judging too much by consumption figures over an incomplete portion of the year. Suppose, for instance, that one driver has handled the van from April to October anti has done 12 miles to the gallon. A new driver then comes On, and it is found that., between October and March, the average is only nine miles to the gallon. It is by no means safe to blame the driver for this falling off in results. It. is probably due to the difference between summer and winter, conditions. In winter the roads are more usually wet and heavy, which increases thes fuel consumption. Moreover, the nights draw in early, and, after dark. the driver must take greater care, and is, therefore, more frequently compelled -to., slow _down and to use his lower gears. This, again, means increased consumption. In some cases users find that the petrol consumed in the winter is almost twice as heavy as in the summer, so that the results taken as an example a.bove might easily mean that the second driver is a better man than the first.
TO some extent, increased fuel consumption in the winter may be attributed to the. engine running too cool.• We do not want, the water to be constantly boiling, but the hotter-it is, short of boiling, the better. If the water keeps too cool, an unnecessary amount of heat from the engine is wastefully dissipated. On sonic vehicles it is a good plan to disconnect the fan behind the radiator in cold weather, so as to reduce the efficiency of tile cooling system.
Trailers and the Law.
The law as it at present stands ie very restrictive of the use of trailers behind motor vehicles.There are plenty of circumstances in which the utility of a motorvan could be considerably increased if a trailer could be drawn. Unfortunately, however, the taw stipulates that, with trifling exceptions permitting. .only of trailers of y-ery light weight., the speed limit of any motor vehicle drawing a traithr shall not. exceed five miles an hour. The consequence of this is that the addition of the trailer is riot yet a practical proposition, except in connection with the heaviest eliiises of motor vehicle, the legal speed of which is, in no ease, high. Thus, a five-ton steel-tyre•d lorry is-itself limited to five miles an hour. If a trailer be drawn,. carrying an additional load, no considerable reduction in the mileage covered results, provided the engine is up to the work, Meanwhile, the tonnage is considerably increased and the costper ton-mile of work done is appreciably reduced.
Directly we come to consider rubber-tyred vehicles the case for the trailer becomes more doubtful. Even ;the heaviest rabber-tyred motors may travel at eight miles an hour. Suppose that the load carried is five tons and the day's work consists of an eight hours' run at the full legal speed. The net result is that five tons have been carried over a distance of 64 miles.
f338
If we multiply tons and miles together we get the total work performed ie useful toe-miles. In this case the result is 320 ton-miles. Now, supposing we were to hitch on a trailer cartying another three tons of useful load, we should have a total of eight tons carried, but the legal Speed being reduced to five miles an hour the distance covered in eight hours would only be 40 miles. The ton-miles of work done would be 40 multiplied by 8 equals 320. So that, by using a trailer, we should not have increased the working capacity of the motor
ehicle. • • It does not. necessarily follow frem this conclusion that a trailer is never worth while in connection with rubber-tyreci lorry. The law as regards speeds is not always observed as strictly as it might be, and trifling breaches of the law are not, always penalized. The Government itself, and other responsible bodies. such as the _Westminster ,City Council, set an interesting, if not completely moral, example in this respect. Moreover, that part of the load that goes upon the trailer may be put into position while the lorry is out on a previous job, so that, by using trailers, we can sometimes reduce terminal delays, which is just as effective as a means of economy as increasing the speed upon the road. It. is to be hoped—and even expected—that, when the law comes to be revised in the neat future, the more free use of trailers will be permitted.
The Economyof Big Tyres.
When purchasing your. first vehicle, if you are anxious to limit first cost strictly, do not indulge in any cheese-paring by getting the. wheels shod with tyres of small dimensions, This is thoroughly bad economy in every way.
For one thing, the small tyres do not afford the same protection to the mechanism of the vehicle against the effects of road vibration. All metal, if subjected to constant vibration, tends to get tired and brittle, and .becomes more liableto break. Moreover, vibration causes wear to all joints and in every place where relative movement of parts is possible. Thus, the use of small tyres is apt to entail the lepair bill being so Much enlarged that any apparent saving more than disappears. MoreoVer, anything that makes for unreliability is bad, because no satisfactory system of deliveries, can be organized, on the basis of vehicles that are not dependable. A breakdown due to insufficient tyre protection may mean a great deal more los:i than corresponds to the more absence of the vehicle from work for a few hours. 1,5 is quite likely to entail failure to effect a number of .urgent deliveries and consequent. loss of custom.
Another point is as follows. Most commercial vehicles are shod with solid tyres, and it is quite apparent that one cannot go on using a tyre until none of it is left; When a tyre is worn out for practical purposes and has to be removed, there still remains quite a lot of the original structure. It is obvious that the thicker the tyre in the first. instance, the bigger the percentage of it that. can actually' be worn away in useful work before it has to bescrapped. Thus, sensible users who go in for tyres of generous dimensions usually find that their tyre bill per mile is thereby reduced. The other items of operating cost cannot conceivably be increased,and many of them are alinut certainly reduced if large -tyres are used, so, altogether, there are many sound reasons in favour of the course suggested in this note.