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Should the Use of the Solid Tyre be Discouraged ?

20th January 1925
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Page 1, 20th January 1925 — Should the Use of the Solid Tyre be Discouraged ?
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Which of the following most accurately describes the problem?

TN AN interview recorded in the pages of this journal a fortnight ago, a point was made brour interviewee about the desire of coachwork departments to get the loading line of commercial motors much lower than is to-day customary, this being one of the controlling factors in the choice of tyre sizes. In the case of passenger-carrying vehicles the tendency is very strong, and, within the next year or two, we shall undoubtedly witness the taking of revolutionary steps in this direction. The first evidence came with the low platform level of the NS-type London bus, which has paved the way to that great desideratum—the covering in of the upper deck. Attention is being paid to this matter, not only by the originators of the movement (so far aa this country and this phase of transport are concerned), but by others who are engaged in the production of motorbuses and motor coaches.

The attitude of diminished intolerance shown to wards speeds which are well above the legal limit is having the effect that might have been expected. Higher speed, particularly in the case of solid-tyred vehicles, is making impression on road surfaces and road foundations, and the conclusion being forced upon all engaged in transport is that, if higher speeds are to be attained and sanctioned, better springing and greater shock absorption are necessary, coupled with the spreading of the load over a greater number of wheels.

What is urgently needed is a lead from the Minis try of Transport in this matter. In Norway, in at least one of the British Dependencies and elsewhere, the use of solid tyres on commercial motor vehicles has been prohibited. A reduced scale of taxation on pneumatic-tyred vehicles applies in Italy, Denmark and the United States, whilst in Switzerland higher speeds are permitted to vehicles so equipped, and some discrimination is contemplated in the projected Motor Bill to be introduced into Parliament this year.

The results of some careful experiments made a couple of years ago at the Swiss Geophysical Observatory at Zurich definitely showed, by means of records on Quervain-Piccard's seismograph, that a vehicle running on solid tyres set up an earth vibration at a distance from the road (93 yds. to 132 yds.) over two and a half times that set up by a similar vehicle, similarly loaded and running at even slightly greater speeds, but shod with pneumatic tyres. Here is direct proof that the damage to the road, the injury to chassis, vehicle arid the goods therein, or the passengers and to buildings adjacent to the road, can be reduced by 60 per cent., which must mean a substantial benefit all round.

It should not be difficult to obtain the use of seismographical apparatus in this country in order to carry out a similar set of experiments here, extending them, however, to include the running of six-wheeled rigid-framed vehicles, loaded, we will say, to the 10-ton limit, because, unless there is an advantage in an increased limit of legal load, it will not be worth the while of any manufacturer to make, or user to try, a vehicle which carries its load upon more than four Wheels. It is this set of experiments which we urge the Ministry of Transport to make as a first step towards the encouragement of measures that will reduce the injury now being done to the roads.

Free Trade in Passenger Transport. Free Trade in Passenger Transport.

LOCAL authorities are greatly perturbed over the decision of the Minister of Transport in the matter of the appeal of the West Riding Automobile Co., Ltd., against the decision of the Bradford Corporation, which, in effect, prohibited the company from running art omnibus service in the city, or of bringing passengers in from outlying districts over routes followed by the corporation's tramways. The law is different now that the Roads Act has removed the final decision in such matters from the bands of the local authorities into those of the Minister, who is empowered to hear appeals, and, if his decision (as in the Bradford case) is in favour of the appellant, to go so far as to issue an order• on his own responsibility authorizing a bus proprietor to run buses in the disputed area.

The existence of a municipally-owned tramway and the fear of competition from a projected motorbus service are no longer grounds for opposition on the part of the local authority responsible for the tramway undertaking. This is clearly recognized in most places—London, for example—yet in Glasgow, Leeds, Wombwell and elsewhere permission for competing bus services to run through the streets under the jurisdiction of the particular authority has, so far, been refused, and it looks as if the Minister's decision will result in an early reconsideration of the applications and a withdrawal of the prohibition, for the circumstances of the various cases are all very much alike.

The Minister's decision in the Bradford ease is not only a decision for free trade, with the reservation that there shall be no war of fares, but it is to be welcomed for the reason that it has seemed, hitherto, that decisions on earlier appeals have preponderated in favour of the local authorities, with some degree of risk that the convenience of the public would not be likely to receive full consideration when a monopoly in passenger transport was granted to a tramways department.

Isolation of the Passenger Vehicle from Vibration and Noise.

OnN PREVIOUS occasions we have referred to the need

for improving 'passenger eemfort in many coaches and buses, and it is interesting to note developments which are occurring in this direction. During a recent visit to the works of a well-known company running a large number of buses and coaches, we examined certain devices which have either been introduced on their vehicles or are about to be so. The ideal at which they have been aiming is completely to isolate the body from the vehicle, in so far as metal connections are concerned, as it has been proved tliat not only does metal convey all the minor vibrations to the body, hut it also forms what might be termed a link through which the sound waves can pass quite undamped. n18 This company realize that comfort does not only lie in the prevention of vibration. The gearbox and axle noises, accentuated by enclosed bodies, may prove most disagreeable and cause a continuous buzzing in the ear, which is a source of annoyance. In earrying out their ideas in this connection, they first mounted the whole body an double rubber cushions earned on brackets disposed round the frame. Each bracket has two cushions—one above to take the weight of the body and one blow to absorb the rebound—and to provide a suitable degree of flexion these cushions are cupped, the interior surface being coned towards the centre in similar fashion to the choke tube of a carburetter, so that whilst the flexibility is considerable for minor vibrations the cushions stiffen up under load.

Not content with this, big pads of rubber were introduced between the spring end slippers and their brackets ; also spring pins and shackles were dispensed with, rollers fitted with rubber tyres and running against suitable slides forming extensions of the spring-brackets being used at each end of each spring.

• To allow for the lengthening of the springs under load, these slides are situated at an angle from the vertical.

The arrangement is such that both the driving and braking stresses are conveyed through the front or rear rubber-tyred rollers, and thus the only metal connection between the rear axle and the chassis proper is through the propeller shaft. This in itself assists in the damping of noises from the axle and its gear ing. The only points where wear can occur are between the rollers and their pins, but here the movement is so slight as to be of little importance ; elsewhere true rolling occurs, and, consequently, there is little or no wear.

Service as a Vital Factor.

.1VIANY of the makers and eoncessionnaires of commercial vehicles have either already developed satisfactory service facilities or are making strenuous efforts to promote this branch of their activities, but there is still much to be done in this direction in the ease of not a few concerns.

Within the past few days complaints have been made to us regarding vehicles ,which were in dock during the whole of the Christmas week, just for the sake of such trivial items as big-end brasses, and this despite the fact that the concessionnaires promised to forward the parts by passenger train immediately they were informed of the predicament. Such happenings are by no means rare, and in some cases have almost disastrous effects on the earning capacity of the vehicles concerned. We know of quite a number of instances in which manufacturers who confidently expected repeat orders for their vehicles lost these entirely through bad service, although their products were satisfactory in every other way. Naturally, service departments have to protect themselves to a certain extent against the risk of parts being ordered and received but not paid for but this seldom happens, and many prefer to despatch parts immediately upon receipt of the order, rather than to offend their customers. On the other hand, it would certainly be a better practice for users always to send a cash deposit sufficient to coves the cost of the parts required. This would give the makers far more confidence and cut out the wastage of time which sometimes occurs where pro-forma invoices are sent and the cost of the parts requested before the despatch thereof. There are other branches of services, including inspection, free advice, etc., but nothing is more important than expedition in the despatch of parts urgently required, although complete interchangeability runs this a close second, and parts should not require machining or a considerable amount of fitting before they can be utilized.

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Organisations: Ministry of Transport
Locations: Zurich, Glasgow, London, Leeds

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