1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152 
More About Recording
Page 47
Page 48
Page 51
If you've noticed an error in this article please click here to report it so we can fix it.
TYRE COSTS MY article which appeared in the December 5 issue of "The Commercial Motor," in which I dealt with methods of recording tyre costs, has brought some further suggestions on this important subject. One letter I received was from the Dunlop Rubber Co., Ltd., in which were given full details of a method planned and recom
mended by that company. , A second communication was in the form of a letter to the Editor: it came from the Firdex Rubber Co., Ltd. It pointed out that there was no. provision in the methods of recording tyre costs which I gave for the value of the rubber in a scrapped tyre.
I will deal with the second point first by drawing attention to yet another method of recording these costs. It is one which was fully explained in "Cost Recording Made Easy," which described a simple system of recording the operating costs of commercial vehicles including, of course, a description of a method of recording tyre costs.
A copy of that particular tyre-record card is given with this article, but I have altered the figures to bring the prices up to date. As with the other two systems I described, this method seems, at first sight, to be rather complicated, but the complication is present only at the inauguration of the system. Once it is put in order and set going it is easy, and little clerical work is needed.
It has, too, the advantage that the costs of individual tyres and the costs to be debited against particular vehicles are shown as accurately as can be. In addition, as I shall show, it completely obviates the risks of the cOmmon error of forgetting to debit the vehicle with the cost of an initial set of tyres.
It is necessary to have one card for every tyre. In a fleet of 10 vehicles with twin real wheels, 60 cards would be necessary. The accompanying table shows such a tyre card completed. On it is recorded the complete history of the tyre, the number of which appears at the top righthand corner. The history starts when the. tyre is first fitted to a vehicle, and in the case of a new vehicle a card will be made out for each tyre and the cost debited as shown on that card.
The card embodies a record of all the vehicles to which the tyre is fitted during its life, of expenditure on repairs, including retreading, and of the mileage it covers to the day it is discarded as scrap. The important thing about this card, however, is that it presents all the eseenttal information from which the cost of tyres for each vehicle of the fleet can be ascertained. In the case of this sample set of particulars, for example, the tyre, during its life, has been fitted to three different vehicles, and the proportion of its life and of its costs in respect of each of the three Vehicles is ascertained and recorded, so that the amounts thus obtained can be set down in the appropriate column in the cost-analysis sheet of the vehicle concerned.
Having the foregoing in mind, it is of interest to know how few figures are needed on the card (Fig. 1). There are actually only eight entries throughout the life of the tyre, a period of five-and-a-half months.
How to Use the System Now to explain the meaning of the headings 6nd the method of use. At the top right-hand corner there is the number of the tyre, which will be found moulded on the , cover, and immediately below that the name of the maker, the size of the tyre and the price.
The first column gives the date, the second and third columns supply information as to the vehicle from which the tyre was removed, and the position it occupied on that vehicle. Similarly, the fourth and fifth columns show to which vehicle the tyre was fitted and its position. The sixth column gives particulars of the mileage the tyre has covered up to the date when any of these removals or replacements is made. There is a seventh column for remarks.
This particular tyre, No. • R.T. 5'68,432, was fitted to the off-side front wheel, as indicated by the letters 0.F., on lorry No. 5 on October 25, 1950. For convenience, I have made this tally with the date on which the vehicle referred to on the cost-analysis sheet was put into operation.
This tyre ran without accident until the December, when
it was punctured. It was removed and repaired and returned to the same vehicle, No. 5, as a spare. It should be noted that during that period it had run 4,765 miles.
On December 8, the spare wheel from No. 5 vehicle was removed and put on to No. 2 in the inner off-side-rear position, as indicated by-the letters I.O.R. Having not been used in the interim, the mileage is still recorded at 4,765.
It is not necessary for me to discuss in detail the remainder of the history of that tyre: it is set out in sufficient detail on the card, but it is of interest to note that in
the course of its life it was fitted to four different vehicles and was finally scrapped after a total of 14,560 miles. Incidentally, it should be observed that, although the tyre was carried by No. 3 vehicle for a time, it was only as a spare, and did not run on that vehicle.
The total cost comprises the sum of all the figures enumerated in the seventh column, that is, £30 initial cost, ' plus 13s. for repair of the puncture, £1 18s. 9d. for repairing a cut in the cover, and £13 for retreading, less the £1 which was obtained for the tyre as scrap. The net cost is E44 us. 9d. and the cost per mile 0.735d.
From the information that the tyre cost is 0.735d. per mile it is possible to debit each of the vehicles with the appropriate proportion of the total cost of £44 its. 9d. Thus, lorry No. 5, on which the tyre ran 4,765 miles, should be debited with £14 I ls. 10d. On No. 2 vehicle the same tyre ran 5,451 miles which equals £16 13s. 10d. On No. 3 it was carried as a spare, so that there is no debit on account of that vehicle, and on No. 4 it ran for 4,344 miles at a cost of £13 55. 2d.
As a matter of interest, and to anticipate possible criticism, I must point out that the sum total of the -debit against all these vehicles does not work out at exactly the total cost, but at £44 10s. 10d. This is to be accounted for by the fact that 0.735d. per mile is a small fraction-ofa-penny less than the net cost.
Now to turn to the Dunlop method. In a foreword the company pointed out that "the initial purchase-cost of a tyre provides little information and can be misleading unless interpreted in terms of cost per mile, and considered in relation to tyre size, type of vehicle and the service conditions involved." I could not agree more. Tyre costs, it is pointed out, are an expensive item and it should be fully appreciated that it is impossible for the operator to determine accurately where improvements and reductions in tyre costs can be effected, • unless he has a detailed tyre record available.
To operate the basic scheme, which' is all that I propose to deal with in this article, only two essential forms arc required. They arc (1), the tyre-record card which is shown in Fig. 2, and (2), the tyre-change form (Fig. 3) or the tyre-change tag (Fig. 4).
The procedure is: When a new or retreaded tyre is received the tyre number, size, cost, make and date of purchase should be entered in the appropriate spaces on the tyre-record card. After the primary information has been entered, the card should be filed until notification has been received through the tyre-change form or a tyre-change tag that this tyre has been fitted to a vehicle. The card is then drawn and the appropriate columns completed.
The entries to be made on the tyre record up to the time that this tyre is scrapped will be apparent from an examination of the column headings. When a tyre is removed for retreading, complete the "Cumulative Tyre Mileage" column and then draw a line across the tyre-record card as shown in the example. This line separates the new tread life from subsequent retread mileages. At this stage, the cost per mile of the new tread may be calculated and entered in the appropriate space on the card.
It is advisable to use the tyre-record card for covers only. Tubes should be dealt with separately, and it is recommended that a simple progressive record of tubes purchased and scrapped should be maintained; it should include details of purchase, size, make and cost. This record can be
analysed at six-monthly or yearly intervals to determine whether the tube consumption appears to be normal in relation to the number of running tyres.
The total mileage of each tyre is the sum of the mileages obtained from the new tread and retread. The sum cost of each new tread is the cost of the new tyre plus the cost of any repairs to the new tread, whilst the sum cost of each retread is the cost of retreading the tyre plus the cost of any repairs to the retread. To obtain the total cost per mile of each tyre, divide the total cost by the total mileage. The method of filing these tyre-record cards is something I have never previously considered. The writer of this Dunlop book, is very nearly in agree ment with me in as much as he suggests that the sequence to be used for filing the tyre-record cards is largely a matter for the operator to decide; many systems have been used in the . past and . all of them have certain advantages and disadvantages.
One method is to file the cards in a straight tyre-number sequence. Special. divisions may be introduced into the sequence to separate tyres of different make or size. Alternatively, or as an addition to the use of these special divisions, the cards may be separated into any of the following groups:— l) All tyres fitted to vehicles, whether on spare or running wheels; (2) usable tyres in stock; (3) tyres being repaired or retreaded; (4) worn-out or otherwise unusable tyres.
The cards may, on the other hand, be 'filed in a vehicle-number sequence. This 'popkilar method employs a series of Vehicle index cards which are filed in a straight vehicle-number sequence. One index card is used for each vehicle. The tyre-record cards for all the tyres fitted to a vehicle are filed immediately behind the index cards for that vehicle. The tyre-record cards are then no longer in numerical sequence but are split up into pockets of from four to 11 or more cards, depending upon the number of tyres on each vehicle.
It will no doubt be appreciated that when the second method is used, it is essential for tyre-record cards to be transferred directly from one vehicle-index card to another when tyre changes occur. If this is not done, 'a search will have to be made through all the tyre-record cards when
Speedometer Reading or Date
No. • Reason for Removal
Signed Date Make Size No.
an incorrectly filed card is subsequently required, The vehicle number should be marked on the visible part of the index card, The remainder of the card may be left blank.
The writer suggests two methods of allowing for the cost of original equipment, and in this connection brings up the point which I have already mentioned, and which I regard as of considerable importance. This is as to whether the cost of original-equipment tyres should be entered on the card.
He suggests; (a) That the tyre cost may be ignored and regarded as part of the vehicle purchase-price: in this event, original-equipment tyres must be omitted from subsequent tyre-mileage and cost calculations, although actual mileages should be recorded on the cards for comparison with general average's; (b) that an alternative method is to enter the tyres on tyre-record cards at their normal purchase prices and subsequently to treat them in exactly the same way asreplacement tyres.
Regular readers of my articles will be aware that I prefer the second of these methods. If it be so adopted, the total cost of the full set of -.tyres must be deducted from the vehicle purchase-price for accounting purposes in order to.. avoid the same charge, being entered in two different
places. , • . The writer draws attention to the , . . .
fact that if this be donethe reduced vehicle cost remaining is artificially low and does not represent the value of the vehicle less tyres, as the price of a vehicle is not the sum of the list prices of its component parts. In other words, the proportion of the vehicle cost debited as tyres will be greater than the actual cost of the tyres as fitted to the vehicle. Whilst agreeing with this, the difference in the values resulting from this method of recording is comparatively small and it can be neglected.
A schedule of abbreviations for wheel positions is suggested and I reproduce it herewith.
There is provision in the booklet, which is called "The Dunlop Tyre Mileage Recording System," for dealing in greater detail with the cost of tyres. S.T.R.