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Page 51
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A warning to other operators
I should like to inform your readers of the treatment I have just received from a major dealer, in the hope that they will not suffer financially in the way I have.
Several months ago I realized I had to do something about my TK Bedford engine which had soldiered on for 105,000 miles without even a top overhaul. After several unsatisfactory enquiries and quotations I called the distributorship concerned and, prior to booking the lorry in, ascertained that the cost of a short motor would be £179 (trade), plus labour £165.56, total £344.56. Add to this the cost of a clutch and some front springs and I fixed a price of about £420.
Imagine my surprise when I was told to pay £516.42. No mention was made at the time of the estimate that in order to guarantee the engine, Vauxhall apparently insist that the radiator, injector pump and various other parts are overhauled. However, had I been told at the time of all these "hidden extras" I most certainly would not have agreed to having the job done.
Even more infuriating is that all these parts are sent out and the dealer has no idea of what has been done to the radiator except the obvious coat of black paint. The stock reply being that they assumed the work was carried out satisfactorily as they had received no complaints in the past!
From the above contents you may think me extremely naive, first for not receiving a written quotation and secondly not realizing all the "hidden extras" are standard practice. However, there may be other readers who are in a small way of business and who are prepared to "trust" a presumably reputable firm. J. F. WILKINSON London, W12
Wheels within wheels?
At the Commercial Motor Show I was appalled to see the British Leyland catherinewheel motif on the Bristol 'VR' and 'LH' chassis that were exhibited. • British Leyland may have responsibility for the day to day management of Bristols and ,even handle their sales, but its shareholding is limited to 50 per cent and the Bristol company is definitely not a mere subsidiary. When I registered my protest I was patronizingly told that the Leyland name would help to sell Bristols, but I believe just the opposite. By rationalizing and eliminating famous names with all their goodwill, British Leyland is simply welcoming into this country the foreign firms like Volvo and Scania as they are the only ones now able to provide effective competition.
I was also dismayed to see no Bristol 'RE' at the Show. Surely while the Leyland National is being introduced — one might be forgiven for saying forced — upon us as a bus there is still a large market, especially among the larger coach operators, for a chassis like the 'RE'.
Is there going to be any future for Bristol? What a pity for the Bus Grants' Scheme the promising 'VRL' design.
I challenge Lord Stokes to comment on his prediction that "Double-decker production would be concentrated and probably increased at Bristol and ECVV". As yet there appear to be no signs of this or of any new Bristol designs for the future.
D.J. SMITH Stony Stratford Bucks
The case for remoulds
"Handyman" (CM August 25) draws attention to the number of discarded tyres and bits of tread to be seen on fast dual-carriageway roads. The evidence is unfortunately true, but in attempting to diagnose the cause he jumps to the conclusion, like many others, that the discards left by the roadside are mostly remoulds. There are no official figures or statistics to support such a statement. As recently as last spring the Department of the Environment stated that there was no evidence to justify any legislation in respect of retreads/remoulds. Specialist retreaders throughout the world have been retreading truck tyres for use at high speeds on such roads as American Turnpikes and German Autobahns long before the UK ever thought of a motorway.
Truck operators know that in the UK there is a British Standard for retreads, in the preparation of which their Associations participated with us. They know that the members of this Association are required to retread to that specification. With the cooperation of the authorities we have had opportunities to examine failed tyres collected from roadways and we can state that the evidence arising shows that remould failures are only proportionate to their share of the market.
Also, most tyre failures are due to causes outside the control of new tyre manufacturers and retreaders. They are due to road hazards, overloading, under-inflation and other maintenance failures which create undue heat when running fast, which inevitably cause the break up of the tyre.
The much maligned retread has served the truck operator well for over 40 years. The tyre manufacturers and retreaders of Europe are at this moment discussing with their respective governments at an international meeting in Frankfurt the industry's recommendations to improve safety standards and preventive maintenance.
P.J. KENT. Retread Manufacturers Association, London SW1.
Keeping it cool
I should like to try and clear up any misunderstanding which may exist in your readers' minds concerning the insulating efficiency of the foamed insulants which are used in refrigerated vehicle 'bodies. Several types may be used, but I would like to confine my remarks to three types: rigid polyurethane foam, rigid p.v.c. foam (e.g. "Klegecell") and foamed polystyrene. Of the three materials, foamed polystyrene can be supplied at densities half that of either of the other two. In the remarks which follow I am considering polyurethane and p.v.c. at about 2Ib /cuft and polystyrene at if Ibicu.ft. Heat transmission measurement refer to a mean temperature of O'C.
Rigid polyurethane foam has a K-value of 0.11 —0.12 BTU in /hr ft OF immediately on manufacture and on exposure to air this value can drift to a final equilibrium value of 0.16 — 0.17. The rate at which this drift takes place depends on whether there is the possibility of air diffusing freely into the material. In an enclosure such as a vehicle body side access of air is extremely limited, so that the change in K-value will be extremely slow. In any event the K-value will not exceed 0.17. However, to allow an adequate margin of safety, engineers use the figure 0.17 when designing refrigerated enclosures. This means that, barring accidents, a vehicle body should perform better than its normal design would indicate, up to the end of its life.
With regard to foamed rigid p.v.c. and foamed polystyrene the K-value of these at best lies, as far as I know, within the range 0.20 — 0.22. They are not subject, to the best of my knowledge, to any ageing effects similar to that described above. However, at equal thicknesses, the polyurethane must therefore always be superior in heat transmission resistance to these and to any other known rigid insulant. Alternatively, a reduced thickness of urethane may be used, thus allowing a greater internal volume for refrigerated cargo.
This argument is not concerned with effects due to moisture ingress or moisture vapour transmission. All three insulants are equivalent to each other in their resistance to moisture and moisture vapour. This is a matter of overall design, with which this letter is not concerned.
D. J. DOHERTY. Section Manager, Application Research & Technical Service Dept., (Rigid Urethane Foam', Organics Division, ICI Ltd, Manchester.
Back numbers
I have for disposal issues of Commercial Motor Nos 3172-3387 — June 17 1966September 18 1970 complete. If these are any use to any of your readers perhaps they would drop me a line and I will be pleased to arrange collection time with them.
N. EDWARD FEW, 24 Pamela Gardens, Eastcote, Pinner, Mddx,