PNEUMATICS SOLIDS?
Page 57
If you've noticed an error in this article please click here to report it so we can fix it.
MANY users of heavy goods vehicles are still hesitating about turning from solids to pneumatics. The question does not arise in connection with smaller machines of Up to 2-ton or even 3-ton capacity. 86 far as public-service vehicles and coaches are concerned the problem is now definitely solved, the solution baying been arrived at by a process of natural selection by the passengers' own choice of the pneumatictyred vehicle.
For goods-carrying machines, however, of capacities of 5 tons and upwards there is still considerable doubt in the minds of users as to whether the pneumatic be really thebetter choice for the work. There is in my mind no doubt whatever of the all-round superiority of the pneumatic tyre for all commercialmotor purposes.
The hard-headed man, however, whether he be haulier or general trader, is still, as regards the majority, in need of some practical demonstration of the benefits of the pneumatic tyre. He is willing to be convinced, but, nevertheless, asks for definite and positive proof.
Tyre-cost Comparisons.
His difficulty is that there are certain real facts of that same definite and positive order which would seem to suggest to him that the opposite view is the correct one—namely, that the solid is actually the more economical tyre equipment. Ile sees that the cost of a set of solid tyres for his 5-ton lorry is about 150 and that of pneumatics approximately £100. He 'does not imagine for one moment that the pneumatic tyre is going to last twice as long as the other. His view is rather that its life will be somewhat shorter, but, even if he allows, for the sake of argument that one will give him the same length of service as will the other, he still has to face the fact that one is just twice as expensive as the other.
To offset this Increase, in cost there appears to be, at first sight, an economy only of taxation, which is somewhat less than £11 per annum. If, therefore, he uses a set of tyres a year, and that is reasonably probable, then, according to his aspect of the matter, he is being invited to spend £50 to save M.
He is told that by using pneuma
tics it is possible to effect savings in fuel consumption and that the cost of maintenance is less. Figures to prove the truth of this statement can be produced, but they are not enough, on the face of it, to turn the scale in favour, of pneumatics.
Our own Tables show that, taking these economies into consideration, the total of running costs is still in favour of the solid-tyred vehicle, the actual figures being 7.4th per mile for the 5-ton solid-tyred machine and 7.64d. per mile for the pneumatic-tyred vehicle of the same 'capacity. The standing charges may be instanced to argue in the opposite direction, the -total for the solid-tyred machine being 1,612th and for-the pneumatic-tyred 1.559d.
By carrying the study of the Tables a little further, however, it is possible to produce that kind of conclusive evidence for which the user is in search, with the effect of solving the problem in what I am convinced is the right way. To facilitate that study I have-set out in an accompanying table figures for the total operating cost of a 5-ton pneumatic and 5-ton , solid-tyred goods vehicle.
It is immediately apparent that up to about 300 miles per week the pneumatic-tyred vehicle is distinctly cheaper per mile than is the solidtyred machine, and that above that mileage the solid-tyred machine begins to have the advantage. That advantage, however, is slight; so slight as to be practically negligible up to 500 miles per week. There the difference is only 0.06d. per mile in favour of the solid-tyred machine; that is to say, approximately 1/200. It will be appreciated that any slight advantage, independent of cost, accruing from the employment of pneumatics, would easily offset that extremely small difference.
To carry the argument further it is necessary to invite the user to look up his own figures for annual mileages. In the majority of cases it will be found that the total does not exceed 15,000, or 300 miles per week, and in all those cases, therefore, there is definite and positive proof in favour of the pneumatic.
It is, however, possible to go even , further than this. Three hundred miles per week, although, of course, far from being the limit of possible mileage for a goods vehicle, is often the most that a solid-tyred goods vehicle can do in the circumstances of its employment, for the reason that its maximum speed on solids is so limited as to curtail its weekly total.
On the other hand, the advantage in point of speed which the pneumatic gives might easily enable that total weekly mileage considerably to be increased, and we thus arrive at this conclusion. Up to and around 400 miles per week the pneumaticAyred vehicle shows a definite economy in point of cost. Above that weekly mileage the pneumatic tyre becomes essential, in any event, in order that that mileage may be within the capacity of the vehicle. On those grounds, therefore, the pneumatic tyre is shown to he definitely superior to the solid.
Increased Earning Capacity.
It is not essential to my argument to refer to the way in which the pneumatic tyre increases the earning capacity of a vehicle, and I speak of earning capacity in broad terms, that is to say, in its application to a trader's use of a machine, as well as that of a haulier. An example showing what I mean by this may be useful as additional evidence in support of my views.
A 5-ton solid-tyred vehicle running 400 miles per week may be employed, shall we say, on an average of eight journeys each week, carrying five tons each trip, making 40 tons in all, at a total operating cost of 1.19 4s. That is equivalent to 9s. 74d. per ton.
A pneumatic-tyred vehicle, by reason of its greater speed, can do 500 miles per week and, working at the same kind of haulage, would, therefore, carry 50 tons at a total cost of £22 8s. That is 8s. 11-it per ton, thus showing a definite economy of not less than 8d. in the cost of the transport per ton. S.T.R.