Growing Use of the Chain Track.
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THE chain-track drive is putting up a stern fight with multi-wheel drive, and what is mere interesting still is the fact that so manY minds are at work upon the design Of vehicles embodying one or other of the above forms of drive, and that manufacturers are taking interest in these salient departures from the conventional two-wheel-driven machines. It will be remembered that The Commercial Motor SOM43 years ago commenced its campaign in the matter of avoiding the destruction of the expensive road foundations and surfaces which were being provided throughout the country from the contributions of motor users to the Road Fund, for it seemed utterly foolish that millions of money should be spent on constructional works that should immediately be subjected to disruption because of undue and unnecessary stresses of weight and drive imposed upon them by heavily laden vehicles.
Since the opening of our campaign, there have been definite advances towards four-wheel, and now six-wheel, drive, and in these matters we are glad to be able to record the fact that British manufacturers are well to the fore in research work, the outcome of which shouldshortly be available for • detailed comment.
Military needs and conditions in undeveloped countries are at the back of the enterprise being shown in different quarters in the use of chain tracks for the final drive, and indre than usually interesting is the fact that Mr. Michael Terry (who made the difficult journey by Ford car across Northern Australia last year, and who has contributed to our pages an interesting article upon a 'transport venture upon• which he embarked in New South Wales) proposes to use chain-track machines for his new ekpedition of 1,500 miles across the Great Sandy Desert in the north-western part of Australia. He regards this journey as the crucial test of the chain track, because, if it cannot stand up to that moderate distance, it will necessarily find the fight against multi-wheel drive particularly hard. and difficult.
Prominent Makers' Intentions for 1925.
ALREADY there are indications that the year 1025 will show a marked improvement in the state of the commercial vehicle market, not only at home but overseas. Even a General Election should have very little effect upon this .industry, and the
gradual settlement which is taking place in Europe is helping to give a stability which, a year or two ago, was sadly lacking.
During recent visits to British manufacturers we have found an atmosphere of renewed hope and a spirit of progress which is decidedly satisfactory and encouraging, and we are cognizant of at least one very Large Colonial order for heavy goods-carrying vehicles which has been given this week. Apart from this there is a constant growth in the fleets employed by commercial houses and, consequently, an increasing need for replacements, for it is indubitably the fact that once mechanical road transport is employed its advantages are so obvious that a return to a slower method of transport is almost unknown. The new subsidy scheme and the encouragement given to manufacturers by the War Department are also causing an increase in interest, and what we may describe as a " certain liveliness on the commercialvehicle front."
The False Economy of Running on Badlyworn Tyres.
TYRE makers are constantly warning users against -11obtaining the last possible mile from their tyres, but, from observation i which we have made, these warnings ppear to receive but scant attention in the majority of instances. Possibly, users are suspicious of the motive of the makers in giving such warnings, and believe that they are not entirely disinterested. From our own experiences, however, and looking at the technical aspect of the matter, ib would seem to us that many users are in this respect "penny wise and pound foolish."
In the case of pneumatic tyres, the vehicle.does not suffer to any considerable extent from the use of worn tyres, because the powers of shock-absorption of a tyre of this type are not .decreased by wear ; in fact, the reverse may be the result, but the user generally suffers the inconvenience of numerous punctures, and even bursts. Also, the tyre which has Worn smooth is of very little use as a non-skid device, and accidents may ensue if this factor be ignored.
As regards solid tyres, the reduction in resiliency can be considered as being more rapid than the wear. It might not be going too far to say that the resiliency diminishes as the square of the wear, and a tyre worn down to within an inch or so of the foundation band is of little use as a shock-absorbing medium, particularly as there is necessarily a layer of hard rubber or vulcanite by which the tread proper is secured to the band. We have even noted quite a number of vehicles bumping along with pieces missing from the tyre treads. It would seem obvious that such a procedure is most deleterious to the running of any vehicle.
Weighing the Tractor-lorry.
THE increasing use of the tractor-lorry type of vehicle has turned the attention of users and prospective purchasers to methods by which these vehicles can be weighed. In certain classes of transport it is essential that the correct weight of the vehicle and its load, separately and conjointly, should be obtained to a highly accurate degree, as it is on these weights that the load carried is often estimated, this applying particularly to such materials as coal and other solid fuels.
Many people are quite satisfied in the belief that the weighing.of a composite vehicle with three axles can be effected on a weighbridge which can only take fvvo axles at the time, by weighing either two first, running these off the lmachine, and weighing the third axle separately, but the experiences of prominent users have shown that this is fallacious, for it is almost impossible to guarantee that the vehicle . will remain perfectly horizontal, there being often a slight drop on to the weighbridge itself, whilst 01.8 the plafform must also sink slightly under the load.
Tests with private and railway weighbridges have shown that weighing in the manner described above may give results which may be either above or considerably below the correct figure. In a specific instance in which various methods of obtaining the weight were employed (these comprising the three axles, weighed separately, the first and second together, adding the third, and the second and third together adding the first) the readings gave differences amounting to a cwt. on the heavy side, and nearly 6 cwt. on the light. This was on a private weighbridge. On a railway weighbridge, the results were slightly better, but even here discrepancies of a cwt. above and below the correct figure were fotmd.
A test load was applied to each weighbridge, and they were proved to give identical readings. The private weighbridge was on a slight gradient, whilst that of the railway had level ground surrounding it, but it is obviously impossible to guarantee accuracy unless all six wheels can be on the weighbridge at once.
The obvious solution of the difficulty is the provision of weighbridges which will take the extra length, but until this be done, accurate weights can be obtained only by weighing all the wheels simultaneously, and we suggest that this could easily be aTected by running two pairs of wheels on the weighbridge and supporting the remaining pair on accurate load-measuring devices such as the bademeter, which was described in our issue for September 30th, or by supporting all the wheels on two baulks of timber laid on the weighbridge.
We would welcome information regarding the experiences of other users of tractor-trailer vehicles in this connection, and as to whether any further solutions of the difficulty have been discovered.
Is There Unnecessary Finish on Commercial Motors ?
TIIE argument is often p"ut forward that finish pays in the long run, that a man quickly forgets the price he has paid for anything, ancrinstead of remembering how much he saved when making his purchase by agreeing to dispense with the finish, will blame the manufacturer -whenever something happens to remind him that the additional work that adds so much to appearance has not been put on to the job.
Yet there is something to be said against the encouragement of the demand for the finishing up of parts that can never be seen except it abnormal circumstances, and for work put into parts which will in no way improve the running or enable better results to be attained. One can instance the finishing to fine limits of the webs of crankshafts, the plating of hubcaps and the production of ultra-smart bodywork as tending to extravagance, and the inflation of manufacturing costs. These refinements are best left until the time when trade has been brought back to normal, and when production costs have been lowered all round to such an extent that refinements in various directions are possible as an alternative to a reduction in catalogue price.
The manufacturer is largely to blame when, at shows, he exhibits vehicles not precisely as standard —because new customers, finding that the standard can be departed from, request additions in accordance with their own ideas and have their enthusiasm damped when they learn that all the fine extras add to the standard price. At the same time, we are quite prepared to admit that a show of commercial motors, standard in every respect, would not be so• attractive as one where polish and nice work were to be seen on every hand. However, the show aspect may be left on one aide for another twelve months, and the question now is—Should all unnecessary work on the chassis and body of, a commercial vehicle be dispensed with until trade has once more assumed normal dimensionsl