Diagnosis: Tyre Maintenance • T • railer Marks L AST week the
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Institute of Road Transport 'Engineers . held its second 'ideas Exchange and Mari" at the Royal Society of Arts. Following a general discussion concerning the affairs of the Institute, Mr. R. B. Daniell read a short paper entitled "Diagnosis." This was in connection with the tracing of faults in Vehicles, which he con sidered a neglected -.subject. • In this he Said,, there were psychological and technical :factors, and where b-oth apply it is often impossible to obtain a solution. Too often it is left to someone who may be a good fitter or mechanic, but lacks a knowledge of human nature, and ends in covering the ,..tracks for anyone following Wm. .Lengthy experience and good knowledge -are not alWays sufficient, unleis a perSdn has a flair for the work and the proper ability to question others.
Defensive Attitude Generally, mechanical considerations follow well-defined lines, and the author wished to emphasize the psychological aspect. When a person is questioned regarding some trouble for which he may or may not be responsible, he is apt to take up an attitude of defence, this varying in accordance with the extent to which the person is implicated, the limits of his technical knowledge and his general outlook. For this reason, questions must be carefully chosen or the answers may be untruths. .
There is a tendency on the part of operators to try non-standard ways of dealing with a trouble. These should always be avoided; in fact, this frequently produces troubles in the first place. If we seek to restore everything to standard, the fault often disappears.
When dealing with a number of complaints of a similar nature, it should not be assumed that they all come from the .same cause. While dismantling to seek an answer, great care must be taken to ensure that any possible evidence is preserved, such as condition of oil, gaskets, colour of working parts, etc. An :accurate diagnosis is often difficult because of the lack of some apparently trifling clue. • Records Essential The keeping of accurate records of vehicle performance is often of considerable value, and this is a feature of Maintenance in whic'h' 'Many sinalkr opera
' tors'fail. They :say that they, have irisuffieient vehicles to,Warrant records, but the author failed to see 'why the -Size— of -a fleet should Make any difference.
Next, Capt. Carlton F. Roberts, chief :engineer, Transport Services, Ltd., gave a short talk on tyre pressures. He 'pointed out that these are striCtly related ..toi axle weights. -There are evils connected with over pressure 'a Mien as with under pressure.
Tyre pressures usually adopted for tyres of various' sizes are invariably the maximum limit and should not be exceeded. A closer study is, however, required to cover conditions where the A32 • axle weight is less than that calling for such a limit. For example, with an 'articulated vehicle the weight on the front axle is always less than that on the front axle of a rigid vehicle, but in practice the tyre pressures for the same size of tyre are often identical.
The Society of Motor Manufacturers and Traders has issued a table for maidmum tyre pressures to cater for various axle weights, but where the weight is exceptionally .high or low, it may be necessary to alter the pressure above or below the S.M.M.T. sdale. For instance.
in the case of an 8-in. tyre, where the axle weight is,85 cwt., the pressure could safely and usefully be raised to 95 lb.; where the axle weight is only 42 cwt., it could be reduced td 65 lb. ".
It is advisable to weigh the axles separately with the vehicle loaded in normal fashion. Vehicles with bolsters for timber carrying or Which may transport abnormal loads likely to increase the weight of the front axle are more difficult to deal with. Then it might be advisable to fix maximum and minimum pressures, leaving it to the intelligence of the driver to raise or lower the pressure within these limits to suit the load carried.
The author advocated the old Army system of painting the pressure limits on the mudguards as a useful guide to those who have to check pressures
Any alteration of pressure resulting from weighing laden vehicles should be pointed out to the driver.
Mr. A. H. Deck contributed a short paper on the advantages or otherwise of fitting signs on or near the front wings of a vehicle to indicate to the front and rear that it is drawing a trailer.
He mentioned that he had suffered shocks on several occasions when starting from a kerb and being compelled to pull out to clear a stationary vehicle. He had waited to follow an oncoming vehicle, only to find a trailer in close attendance. He suggested as an alternative the possibility of something like a railway signal arm with a prominent and illuminated T, which could Swing out of the way when not required, or an illuminated triangular box with T signs, mounted on the panel forward of the cab door.
The chairman, Mr. G. Mackenzie Junner, gave a brief talk on metal tyres, and one member said that he was using steel-carcase tyres with great success.
P.T.A. CONFERENCE PLANS
APRELIMINARY programme of the 1948 Conference of the Public Transport Association, to be held at Eastbourne, has now been issued.
On the afternoon of May 4, the Maynard Cup Golf Competition will take place, and in the evening there will be an informal reception by the chairman of the council. On the following morning the annual general meeting will be held, after which a paper will he read and discussed. The Association's annual dinner or special buffet and dance will take place in the evening.
On the morning of March 6, there will be another paper and discussion, and in the evening a civic reception and dance.
The Conference headquarters will be at the Grand Hotel.
TRANSPORT FIRST, SAYS M.P. LTHOUGH the Government was IA launching a great scheme of further production, there were groundnuts in West Africa that could not be moved because of lack of transport, said Mr. Baldwin. in the House of Commons, last week.
He believed that money would be better employed on the development of railway and road transport of the African Colonial Empire, rather than on primary production. "This can be better done by private enterprise," he said.
As reported in The Commercial Motor" last Week, Vauxhall Motors, Ltd., is supplying 750 Bedfords for the groundnut scheme in East Africa.
TOUR PASSENGERS HOLD REUNION
TWET's;TY-EIGHT passengers who, last year, took an extended tour of Devon with the Northern General Transport Co., Ltd., became such firm friends that they recently held a reunion at a Newcastle-on-Tyne hotel. Ihey invited the driver and his wife, and at the end of the evening arranged to book for another tour next summer.
The company promised to give the services of the same driver, who has been with the "Northern General" for 32 years, and for the past 20 years has been working on extended tours. RATES PRORLEN FOR 1LT.C. nNE of the gmetest problems for the %.-/British Transport Commission would be the establisliment'of, a suitable and equitable form of charges, said Mr. W. Farnorth, Area Executive Officer of the Road -Haulage Association, when discussing the effects of nationalization at the January meeting of the Manchester Centre of the Insti tute of Traffic Administration. The only fair arrangement was to establish a system of inland transport on the basis that traffic should gravitate to the form of carriage most suitable for it.
In the Manchester district the R.H.A. was likely to lose nearly half its subscription income when nationalization became effective, said Mr. Farnorth, who forecast the possibility of an increase in local importance of the Association, With a probable decrease in R.H.A. headquarters' work..