PROBLEMS OF THE HAULIER AND CARRIER.
Page 64
Page 65
If you've noticed an error in this article please click here to report it so we can fix it.
Some Points with Regard to Tyre Costs—Keeping a Tyre Diary and Applying the Information thus Recorded.
A PRACTICE adopted by many of the large con.ri. cerns operating fleets of commercial vehicles is the keeping of a service record of individual tyres. Owners of small fleets or single machines would do well to follow the same plan. It is impossible for the ownerdriver who has to keep check on even so few as four, five or at the most eight tyres on one chassis to remember the detail behaviour of one and all throughout their life, their failures and so forth.
That it is important to record the incidents in tyre life is obvious, as the cost of this part of the chassis equipment is considerable, almost equalling that of fuel per mile in some cases. By means of the use of a tyre diary the annual bills may be reduced. There is no necessity to make an elaborate affair of it, merely an accurate record of expenditure and a brief history of the work obtained which can be used as a guide to the quality of the various makes, to prevent recurring trouble where the cause can be traced to a chassis defect consequent upon the warning to be derived from the diary, and as an indicator for proper tyre maintenance which leads to the longest efficient life.
Entries in this diary will be comparatively few and made at occasional intervals, so that the addition of this book to the number ordinarily kept cannot be regarded as an extra task of a wearisome nature. The trifling labour involved, however, can be rewarded many times over if one be careful to learn the lessons offered by the diary. A simple system is to put down at the top of one page of the book the number or numbers of a tyre, together with its description and size, one page being kept for each tyre. These numbers are useful not only for identifying any tyre in which one may be interested for the moment, but may be handy data in the case of theft of the vehicle—it is a disquieting thought that but few people could give the police much help by furnishing a complete series of points for identification in event of theft.
Beginning the Record of the Life of the Tyre.
Reverting to the book, next rule a line across the page to separate the heading from the entries. In the left-hand column of each page the dates may be put down in respect of each item. It is also important to record the mileometer readings beside each event.
Starting with a new tyre, after completing the heading and ruling the line, put down the date of the commencement of service and the mileometer reading. The latter point is the basis for all future calculations of tyre life and it is therefore imperative to record it. To derive the greatest benefit from the book, the wheel on which the tyre is fitted should be noted ; the entry will read something like this: 1-1-27. 12,640. Near-side front. Purchased for £4.
All subsequent incidents should be noted so soon as conveniently possible after the occurrence. For example, a vehicle with splayed front wheels shod with pneumatics is apt to incur more wear on the outside of each tread. From time to time, therefore, it is advisable to change the tyres round so as to equalize the rate of wear. Whether this be done by fitting the cover the other way on the wheel or by interchanging the front wheels is a matter of choice or mechanical design, but whichever course is adopted the action should be recorded; the entry may appear thus:— 9-3-27. 16,760. Tyre refitted to near-side front wheel
to equalize wear.
When a failure occurs this must be entered together with the repair costs, as these charges have to be included in the total expenditure connected with the particular tyre. Say, for example, a part of a broken
c42
horseshoe penetrates a cover ahd tube and the damage is repairable by vulcanization. The diary will show something like this: 11-3-27. 16,900. Large puncture. Cover vulcanized, 10s. 6d.
Two other entries will have to be made in connection with the same event, namely, one for the damaged tube and one for the spare-wheel tyre recording its date of beginning service in the near-side front position and the appropriate mileometer reading. Proceeding farther with the original tyre, we will presume it is carried as a spare until another puncture calls for its fitting— this time in the right-hand rear position ; the diary then shows:— 14-4-27. 18,100. Off-side rear.
Finally, the tyre is scrapped and the summary of its history is due. The closing entries will be as follow:21-8-27. 22,200. Scrappect; A line is here ruled across the page and the cost per mile worked out this :— Cost per mile equals .1,299d. for this cover.
So much for the general System of keeping the tyre
diary. There are a few points which it would be well to bear in mind in connection with its compilation. When a new vehicle is bought, the tyre purchase price should be separated from the vehicle cost, as the general depreciation of the vehicle is a separate and distinct item from the tyres and the two must not be dealt with together.
The depreciation rate per mile for the chassis and body is, of course, calculated on the price of the machine, less the tyres, and the tyre cost per mile Includes the original purchase price of the tyres, plus subsequent repairs and renewals. Hence it is important when fitting a new tyre or when starting a diary for a new vehicle to see that the cost of each cover or solid tyre is entered alongside the date and mileometer reading. Covers and tubes should be kept separate; that is, a page devoted to each item. To obtain the total tyre costs for a year, it is only necessary to add up the total expenditure for all covers and tubes and divide the result by the number of miles accomplished by the vehicle during that accountancy period.
The owner can use the diary, as already mentioned, as a means for comparing the qualities of the various makes or tyre; for example, he finds that a Blank cover has given a result of id. per mile, whereas a rival make has cost 1.12d. per mile. The inference is obvious so long as the two covers have been working under approximately equal conditions. Should, however, the more expensive tyre have failed because of some outside cause, such as running over a broken bottle, the diary should show this in order to prevent a hasty conclusion being formed as to the respective merits of the two tyres. Where several covers of one make can be grouped together and compared with an equal number of the products of another manufacturer a more reliable result can be obtained, and the diary again proves its value in this connection.
It often happens that tyre failures are caused by some chassis defect, such as incorrect front-wheel alignment or a buckled wheel. A study of the diary may show, for example, that the near-side front tyre has worn out in a short period of time and that its successor has been equally unfortunate. The inference is that a mechanical defect should be suspected, and if examination reveals the trouble a note should be entered in the diary to the effect that it has been rectified.
It is impossible for an owner to carry in his mind the date and mileometer reading coincident with the interchange of the two front covers for the purpose of equalizing tread wear, but the diary is a handy record of the job and a glance at its pages will suffice to show when the time for a further change is drawing nigh. Examples of the utility of the plan of keeping air individual tyre record can be multiplied, but such action would serve little goodpurpose here. I trust that what has been said already will be sufficient to point out the value to the commercial-motor owner of keep
ing this tyre data. S.T.R.