Opinions from Others.
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The Editor invites correspondence on all subjects connected with the use of commer ial motors. Leiters should be on tine side of the paper only, and type-wrOten by preference. The right of abbreviation is reserved, and no responsibility for views expressed is accepted. In the case of experiences, names of towns or localities may be withheld.
The Editor, TEE COMMERCIAL MOTOR.
 Sir,—I note that a .memorial has been presented to the Board of Trade by the Roads Improvement Association with regard to traffic congestion in London, much of which is alleged to be caused by the County Council tramways. Is it not time that everyone paused to consider if the tramways are now necessary, especially in view of the new omnibus companies which appear to be cropping up so plentifully'? The danger of boarding a car, or of alighting from it, in the middle of other traffic, is, at the present time, very great. There is considerable difficulty siways experienced in reaching a tramcar in safety within the bounds of the Metropolis. This is a risk to life and limb which is, of course, not character istic of the motorbus. When tramways were first introduced, traffic was not what it is to-day, and I think modern conditions have become so d.fferent that it behoves us to consider whether the tramway is not only obsolete but, at the present time, a danger to every other user of the road.—Yours faithfully, EDWIN E. HILL.
Springbourne, Bra.ding, Isle of Wight.
The Shepherd "Easily-Tired Wheel.
The Editor, THE COMMERCIAL MOTOR.
LI492] Sir,—In reply to " Hexagon's " letter in your issue for the With ult., I should like to say that .I agree with him in much that he says. Especially am .I with him when he quotes his experience as to the variation in size of the steel bands of rubber tires. Such variation has been a stumbling block for all inventors of detachable tires. I propose having a taper on the hub mounting of I in 12. Then, say, for argument., that the reputed diameter of the steel band of the tire should vary as much as 1-16 in., the whole wheel itself would be located about in. ..nearer to the hub flange. If the hub taper were I in 16, the horizontal displacement of the wheel would be nearly 1 in. Even if this happened, as your correspondent suggested, I fail to see that there is any disadvantage. The effect of the spokes not being clamped tightly to the flange would be that. the strain on the bolts then induces bending instead of pure shear, but in this connection " Hexagon " has omitted a most important point. The effect of pulling the taper on to the boss tightly would he to take the drive in the same way as a friction clutch does. I also suggested --fitting a key or keys the bolts could not, under such conditions, possibly keys; the driving strain. In conclusion I would add that the rust question affects this form of wheel less than it does any other type with which I am acquainted. Ample means for removing the wheel are provided by a set screw in each spoke. The taper mounting enables displacement to be effected very readily ; when the rim is turned the gap would be left open about !, in. This would allow for the wheel to be contracted much below the normal size if it were found necessary in order to remove the tire. I dismiss your correspon
• dent's suggestion of taper hexagon cones ; it is so utterly Unpracticable on manufacturing grounds. I am much obliged to " Hexagon " for the interest be has taken in this matter, as also for his practical
• eriticism. The detachable-tire question apparently .appeals to both of us. I regret that your correspondent has felt. it necessary to conceal his identity -uricter -a nom de plume.—Yours faithfully, One-horse Van v. Motor-van.
The Editor, THE CO3IMERCIAL MOTOR.
 Sir,—I have read with pleasure the interesting comparison given in your issue of the 1st inst.
between an average " winner " and a 10-15-cwt. motorvan. There are a few of the figures, however, which are open to criticism.
With regard to the horse-van, why should the rent,
rates and taxes in 1909 and also the stable labour be greater than in 1911, when the tendency for this
expenditure is to be on the increase 1 Does insur ance include accidents to and value of the horse'? If so, I should much like to be placed in communica tion with the insurance company willing to undertake the risk at so low a rate ? Next, as provision is made for veterinary charges (so that the horse itself cannot be included in this item). it therefore only applies to the van, but I do not think it can be reasonably contended that the cost of repairs to a motorvan, on an average, are no more than Is. 6d. per week over the cost of repairs to a horse van. Interest and depreciation are put at 4s. 8d. weekly, and the capital value of the horse is given at £90; this, at 4 per cent, will give for interest about is. 40. per week, leaving 3s. 3/id. as the proportion for depreciation, or Ls us. 2d. per annum, which gives a life of over 10 years. This may he reasonable for a horse employed solely in the country, but not for one in a large town, where the constant strain of starting on account. of traffic stoppages soon has its effect., to say nothing of always working on the hardsurfaced roads.
With regard to the motorvan, the figure for insurance is very small, as it works out at less than 26 per annum. Presumably, it is only for limited risks? The repairs are placed at 211 11s. per annum, but I do not think that any repairer would be willing to take on a maintenance contract for say a period of five years at this rate. Interest and depreciation, at 14s. weekly, give for interest at 4 per cent. about :is. 10d. per week, leaving 8s. 2d. for depreciation, or 121 is. per annum, which on the capital value of 2380, less tires at say 250, works out on a life of nearly 16 years. The motor industry has no doubt improved its products immensely, but it has hardly reached this state of excellence yet.
I note that the motor driver is allowed is. per week more than the horseman—not much of an encouragement for a man to take an interest in the working parts of his machine, allowing for the probable shorter hours on the road. In the 1909 figures, it is stated that they are taken on a basis of a 60-hour week but later it is asserted that those who know give the vanner's working hours from 45 to 50 hours a week.
From the above, J think, Sir, that you will grant that the figures given are not so complete as could he wished to enable the trader to obtain an accurate idea of the relative costs of horse and motors.Your
faith f lly, "ACCOUNTANT."
The Figures are actnal to date. except for depreciation on motorvan. If a" vane er " can work for 45 hours, it can presumably loiter for another 15, weekly. The IOW depreciation and other low motorvan charges, it is perhaps01 erlooked, concern a vehicle doing only 20 miles a day. That is onethird of normal work for a motorvan. The value of the horse was nnt stated at £90: that was given as the value of the horse, van and harness. Threatened and current competition of motorvans has led to the slight reductions for rent and stable labour, in respect of the horse-van, since 1509. We have now ascertained that " repairs '' in the horse acreunt, include small payments for accidents not covered by insorance, as well as repairs to harness. In both accounts, under insurance, the owners carry the first £5 of any and all damage. The actual expended repairs to the motorvan are 'Md. per utile in 24 years, and the balance is made up by small parts bought for stock and not yet used. The motorvan has been
free of accidents.-En.)