DVRING the last three weeks I have been obliged, with
all due regret, to refuse no fewer than five Spectator readers information I was supposed to possess. These five (and, incidentally, many times more than five at other times) wanted to know what motoring costs. Up to a well defined point I could perhaps have told them, but I could not pretend to the profound insight so flatter- ingly credited to me.
They wanted me to draw up estimates. of costs over periods of one, three and five years, for 10, 18 and 25- horse-powered cars, with supplementary estimates for cars bought secondhand with 10,000, 20,000 and 50,000 miles' work behind them and nobody knew how many owners or of what sort. I doubt if anybody living has such knowledge. AcCounts would have to be kept of such closeness as must forever sour the joy of possession, and even if there were anybody who had stored in the cellar the uncountable tomes of such calculations he would, unless a genius, have little of interest to tell us about the cars themselves. A grocer might tell you how the candle-market fluctuates, what the difference is between the sugar situation today and that of three years ago, the trend of pepper, working out all these palpitating problems to eight places of decimals. But does he know how the 1929 candle compares with the 1933, whether pepper is hotter today than it was before it got into the news so strikingly ? Of course not. He has no time for such irrelevances.
Given a number of known facts about a new car, it is possible to estimate what it will cost per thousand miles—a better unit, perhaps, than a single mile, but even so there are possibilities of miscalculation that some inexperienced owners might never suspect.
If you are buying a car built by a famous factory, with a famous reputation to lose, and are paying a considerable sum of money for it, the chances of working out an accurate estimate of its working costs are good. You know that nothing experimental is allowed in any new model, that no essential will fail. There are some makers who, for reasons of economy, are obliged to leave the testing of new ideas largely to their customers, while others spend money on proving to their own satisfaction the claims of the inventors, incorporating the new departures in the cars they sell to the public only when they are proved to be economically beneficial. You should therefore be able to say of car A or car B that, with ordinary luck, it will not or may not need a serious replacement for the first so - many thousand miles.
If you know its weight—and it is always wise to get this rather evasive figure settled—the load it will usually carry, the average type of country it will encounter, hilly or flat, rough or smooth, and the general maximum speed at which it will be driven, you can work out pretty closely what it will cost you in petrol, oil and repairs for the first five periods of, say, 10,000 miles. Take a car of 20-h.p., for example, weighing -30 cwt., of first-class manufacture, which has cost you something over £700. You will probably find that it needs a gallon of oil for every 1,000 miles run plus the normal content of the sump. That is to say that if the sump holds two gallons. you will have to buy three gallons for every 1,000-miles, one for loss in working, two for renewal. This figure should not vary perceptibly until the cylinders require reboring, and I doubt very much if anybody really knows when that moment is likely to arrive for any first-class car. A well-cared-for engine will run as much as 80,000 or 90,000 miles without having to have a rebore, while another exactly similar in every respect which has been, if not neglected, at least harshly and un-economically treated will show signs of sloppiness and therefore of oil- extravagance in half that distance. For an average, make it 50,000 miles. After that you must expect to find the oil-consumption increase pretty consistently. Petrol consumption is no longer the bogey it was until a few years ago, and one is relieved to see cars are not so often sold (or at all events - advertised) on their fuel- economy. Broadly but fairly truthfully speaking, one car is or can be as economical as the next, and there is very little the owner can- do to improve it. The amount of petrol used depends to an astonishing extent upon the manner in which the car is driven, far more than upon the sizes of jets and choke-tubes. Continuous high engine- speed is the first enemy of economy, with too small jets a good second. If you use smaller jets than the maker fits you will do little more than spoil the performance and burn the exhaust-valves. The consumption will remain the same or nearly, but the running costs will go up because you will have to re-grind or renew the valves. Also you will infallibly take a dislike to the car and sell it—probably, in your haste, for less than you •should get. A sound rule is to fit large jets and open the throttle as little as possible. Technically speaking, I dare say this is all wrong, but a good many years' bitter experience persuade me that it works. My own car has jets two sizes larger than those recommended, and the petrol consump- tion is what it was originally supposed to be, and what it always has been, after eight years. The exhaust valves are models of unpittedness.
For the purposes of your estimate you can safely take the makers' advertised petrol-consumption and deduct say 10 per cent. for safety. If the car is expected to do 20 to the gallon, read it as 18. This is not written in any criticism of makers' claims, but merely to broaden the margin of error. Besides many a car that will do 20 to a gallon over 100 miles may only show 18 over 1,000 or more, but 22 over another distance. Wind and weather, hills and levels, and, above all, extra load make a lot of difference.
Tyre-wear is the easiest of all expenses to compute today. Provided you keep them correctly inflated, frea from flints, and use brakes and acceleration reasonably, they should last at least 15.000 miles on modern road- surfaces, sometimes more. Generally speaking, there is nothing more to be said about tyres.
With an expensive car, therefore, you nearly know where you are. You can work out the running cost per 1,000 miles to within a- very little. Remain certain replacements, the cost of which it is impossible to calculate with any accuracy. You may be unlucky in accessories, in lamp-bulbs, in sparking-plugs (most unlikely), in coachwork defaults, in all sorts of oddments. You should never have to replace anything expensive. With a cheap car about whose reliability over big mileages you can obtain no certain knowledge, you can only work on the running costs for a short period, say 10,000 miles. At the end of that time, if you still know nothing about its probable future, exchange it for a new one. Some cheap cars are marvels of economy and reliability, but it is as well to remember that no cheap piece of machinery can possibly be as well made as a dear one. It is good business to get the best out of it and then sell it.
Unless you have a personal and intimate acquaintance with a used car, and know every incident of its life as well as every fault of its driver, it is quite impossible to guess at what it will cost per thousand miles after you have bought it. You may get a marvellous bargain and you may not. Your chances are better today than they have ever been—but they are still chances.
JOHN PRIOLEAU.
[Note.--,Readers' requests for advice from our Motoring Correspondent on the choice of new oars should be accom- panied by a stamped and addressed envelope. The highest price payable must be given, as well as the type of body required. No advise-can be given on the purchase, sale or exchange of used cars.]
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